True/False
1)A hydrometer test cab be used to determine the grain size distribution of silt and claysized particles. (True)
2)In the USCS, the Plastic Limit is used by itself to define and determine if a clay is High
Plasticity (CH) or Low Plasticity (CL). (False)
3)Compaction is the process of increasing soil density by any means including squeezing out
water. (False)
4)A sieve analysis test can be used to determine the grain size distribution of silt and clay
sized particles. (False)
5)In the USCS, the Liquid Limit is used by itself to define and determine if a cay is High
Plasticity (CH) or Low Plasticity (CL). (True)
6)Compaction is the process of increasing soil density by reducing air volume only. (True)
7)A sieve analysis test can be used to determine the presence of silt and clay sized particles.
(True)
1) Pycnometer can be used in The Unit Weight Test to evaluate the sample volume
(F)
2) Increasing the number of drops in The Liquid Limit Test means decreasing water
content (T)
3) In The Hydrometer Analysis Test, sieves must be arranged in order the large
diameters top (F)
4) Collection of water in The Falling Head Test must begin after reaching a steady
flow (F)
5) Modified Proctor Test applies more effort to the soil compaction than the Standard
Proctor (T)
6) To prevent water drainage in The Consolidation Test, porous stone layers can be
used (F)
7) Cross section area of the sample during The Unconfined Compression Test remains
constant (F)
8) In the Direct Shear Test there are only three dial gages to be read (T)
9) In the unconfined shear test σ 3= 0 (T)
10) The dial gage reading decreases in the unloading stage of the Consolidation Test
(T)
11) Soil grains are incompressible. Their mass and volume remain the same at any
void ratio (T)
12) Atterberg limit tests are performed on oven dried soil passing the 400 micron
sieve (F)
13) In the Direct Shear Test the shear distribution over the shear surface is assumed to
be uniform (T)
14) Dry density is greater than submerged density (T)
15)Standard proctor test results in a higher values in relative compaction than that’s of
the modified test (T)
16) Specific gravity is defined as the ratio of the unit weight (density) of a given
material to the unit weight (density) of water (T)
17) A body submerged in water will displace a volume of water equal to its own
weight (F)
18)Hydrometer analysis is based on "Stokes’ law" The smaller the grain size, the
greater its settling velocity in a fluid F
19) In Hydrometer test the meniscus correction accounts for the effect of using a
deflocculating agent (F)
20 Constant head method is more efficient for clayey soils but Falling head test is
more efficient for sandy soils).F)
21) Liquid limit is the moisture content (%) at which the soil when rolled into threads
of 3.2mm in diameter, will crumble (F)
22)Casagrand device is used to measure the plastic limit( F)
23) Plastic limit is measured during penetration method using a penetrometer device
(T)
2021/1/10
Density Index & Relative Compaction - Soil Mechanics Questions and Answers - Sanfoundry


Soil Mechanics Questions and Answers –
Density Index and Relative Compaction
« Prev
Next »
This set of Soil Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Density
Index and Relative Compaction”.
1. The density index ID does not express the relative compactness of a natural cohesion-less soil.
a) True
b) False
View Answer
Answer: b
Explanation: The density index is used to express the relative compactness or degree of
compaction of a natural cohesion-less soil deposit. It is also known as relative density or
degree of density.
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Density Index & Relative Compaction - Soil Mechanics Questions and Answers - Sanfoundry
2. The term density index ID is used for cohesion-less soil only.
a) True
b) False
View Answer
Answer: a
Explanation: The term density index ID is not applicable to cohesive soil because of
uncertainties in the laboratory determination of the voids ratio in the loosest state of the soil
(emax).
3. The formula for density index ID is ______
a) (emax – e)
b)
c)
d)
(emax –e)
(emin−e)
(emax –emin)
(emax −e)
(emax –e)
(emax −emin)
View Answer
Answer: d
Explanation: The density index is de ned as the di erence between the voids ratio of the soil
in its loosest state emax and its natural void ratio e to the di erence between the voids ratio in
the loosest and densest state.
ID=
(emax –e)
(emax −emin)
.
4. When the natural state of cohesion-less soil is in its loosest form, its density index ID is equal
to ____
a) 0
b) 0.5
c) 1
d) 1.5

View Answer
Answer: a
Explanation: Cohesion-less soil is in its loosest form will have its void ratio e=emax.
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Density Index & Relative Compaction - Soil Mechanics Questions and Answers - Sanfoundry
Since ID=
ID=
(emax –e)
(emax −emin)
(emax –emax )
(emax −emin)
ID=0.
5. The density index of natural deposit in its densest state is ______
a) 0
b) 0.5
c) 1
d) 1.5
View Answer
Answer: c
Explanation: Cohesion-less soil is in its loosest form will have its void ratio e=emin.
Since ID=
ID=
(emax –e)
(emax −emin)
(emax –emin)
(emax −emin)
ID=1.
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6. A soil has porosity of 30%. Its voids ratio in the loosest and densest state is 0.35 and 0.92
respectively. What will be its density index?
a) 0.865
b) 0.872
c) 0.861

d) 0.881
View Answer
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Density Index & Relative Compaction - Soil Mechanics Questions and Answers - Sanfoundry
Answer: c
Explanation: Given,
Porosity of 30%=0.3
voids ratio in the loosest state emin= 0.35
voids ratio in the densest state emax=0.92
n
e=
(1−n)
e=
0.3
(1−0.3)
e=0.429
ID=
ID=
(emax –e)
(emax −emin)
(0.92–0.429)
(0.92−0.35)
ID= 0.861.
7. The density index ID in terms of densities is given by ______
a)
(γ d,max−γ d,min)γ d,max
b)
(γ d −γ d,min)γ d,max
c)
d)
(γ d,max−γ d )γ d
(γ d,max−γ d,min)γ d
(γ −γ
)γ
d
d,min
d,max
(γ −γ
)γ
d
d,max
d
(γ d −γ d,min)γ d,max
(γ d,max−γ d )γ d
View Answer
Answer: b
Explanation: The density index is given by,
ID=
(emax –e)
(emax −emin)
e = (
Gγ w
) − 1
γd
Gγ w
e max = (
e min = (
γ d,min
Gγ w
γ d,max
) − 1
) − 1
substituting the values of voids ratio
ID=
((
((
ID=
Gγw
γ
d,min
Gγw
γ
d,min
)–(
)−(
Gγw
γ
d
))
Gγw
γ
d,max
(γ d −γ d,min)γ d,max
(γ d,max−γ d,min)γ d
))
.
8. The relative density of loose granular soil is given by the range ______ in percentage.
a) 0-15
b) 15-35
c) 35-65
d) 85-100

View Answer
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Density Index & Relative Compaction - Soil Mechanics Questions and Answers - Sanfoundry
Answer: b
Explanation: The following table gives the characteristics of density of granular soil on the
basis of relative density.
Relative Density (%)
Density Description
0-15
Very loose
15-35
Loose
35-65
Medium
65-85
Dense
85-100
Very Dense
9. A soil has a dry density of 17.5kN/m3. It has densities corresponding to most compact and
loosest state as 18.5 kN/m3 and 13 kN/m3 respectively. The relative density of the soil is ______
a) 0.871
b) 0.865
c) 0.869
d) 0.860
View Answer
Answer: b
Explanation: Given,
Dry density γd=17.5 kN/m3
Maximum dry density γd,max=18.5kN/m3
Minimum dry density γd,mim=13kN/m3
Relative density ID=
ID =
(γ d −γ d,min)γ d,max
((γ d,max−γ d,min)γ d )
((17.5−13)∗18.5)
((18.5−13)∗17.5)
ID=0.865.
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Density Index & Relative Compaction - Soil Mechanics Questions and Answers - Sanfoundry
10. The relative compaction Rc is given by _______
a) γd,max/γd
b) γd/γd,min
c) γd/γd,max
d) γd,min/γd
View Answer
Answer: c
Explanation: The relative compaction Rc is de ned as the ratio of dry density γd of soil to its dry
density corresponding to most compact state γd,max.
Rc = γd/γd,max.
11. When the soil is in loosest form, density index is zero and its relative compaction Rc is ______
a) 40%
b) 60%
c) 80%
d) 100%
View Answer
Answer: c
Explanation: The relationship between the relative compaction Rc and density index ID is given
by,
Rc=80+0.2ID
When ID=0,
Rc=80+0.2*0
Rc=80%.
12. The relative compaction Rc is related to the void ratio of soil by _______
a)
b)
c)
d)
(1+e)
(1+emax )
(1+e)
(1+emin)
(1+emin)
(1+e)
(1+emax )
(1+emin)
View Answer

Answer: c
Explanation: The relative compaction is given by,
Rc =
γd
γ d,max
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Density Index & Relative Compaction - Soil Mechanics Questions and Answers - Sanfoundry
Since γd=γs(1+emin)
γd,max=γs(1+e)
∴ Rc
=
Rc =
γd
γ d,max
=
(1+emin)
(1+e)
γ s (1+emin)
γ s (1+e)
.
Sanfoundry Global Education & Learning Series – Soil Mechanics.
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Soil Science Midterm 2
Study online at quizlet.com/_147w6
1.
the active soil acidity is defined as the
hydrogen
and al in the
soil solution
2.
the active soil acidity is defined as the
hydrogen
and
aluminum in
the soil
solution
3.
an alkaline ph8 soil with 50%
montmorillonite clay and 5% organic matter
content will have a high
shrink swell
potentional
4.
aluminum is considered a_______cation
because____ions are produced during
aluminum hydrolysis
acid,
hydrogen
assume you want to grow azaleas in a soil
with a ph of 6. The application of which of
the would be most appropriate to make the
soil suitable for this ornamental
elemental
sulfur
as the percent basic cation saturation of a
soil decreases the,
acid cation
levels
increase
7.
as the percent basic cation saturation of a
soil increases, the
basic cation
levels
increase
8.
because of their greater surface area per
unit of soil mass, silt loams soils generally
have a greater capacity than loamy sandy
soils
need to
answer
9.
brown and red colors in subsurface horizons
are caused by ____in soil
iron oxides
10.
Calcium is considered a ___cation and is
derived from the weathering of
basic, calcite
11.
Capillarity in soils
involves both
adhesion and
cohesion
12.
Cation that you would expect to be most
tightly held in a soil pH 4.5
Al3+
The CEC alkaline soils are generally higher
than those of most acid soils of similar
texture Which of the following
characteristics of alkaline soils most likely
account for this high CEC
need answer
14.
Characteristics of Soil Colloids
need to
answer
15.
a clay loam soil with a pH of 9.5 will have a
low
hydrogen ion
concentration
16.
a clay loam soil with a pH of 9.5 will have a
low
soluble
aluminum ion
concentration
5.
6.
13.
17.
a clay loam soil with a ph of 9.5
will have a low
soluble aluminum iron
concentration
18.
clay mineral which is most often
responsible for swelling and
shrinking in soils is
montmorillonite
19.
a clay soil derived from basalt
would contain high amounts of
montmorillonite and iron
oxides
20.
a clay soil low in organic matter
in the mojave desert will
have_____ in its epipedon
low humus content
21.
clay soils have higher
average__values than sandy soils
total water holding
capacity
22.
colloidal properties are exhibited
by the ___fraction of soil
clay
23.
a decrease in porosity results in
an increase in bulk
density
24.
the difference between the
liquid and plastic limits of a soil is
the plasticity index
25.
the drainage class of a soil is
directly related to its
need answer (bulk
density?)
26.
The drainage of certain wetlands
can result in extreme soil acidity
because
oxidation of sulfurbearing minerals that
produces sulfuric acid
27.
dull gray colors are
characterized by
low chromas
28.
environmental concerns related
to ag soil drainage systems
include
disposal of drainage
water containing salts
and toxic elements
29.
the exchange complexes of
strongly acid ph4.5 mineral soils
are saturated mainly with
exchangeable Al3+ ions
30.
Expect downward movement of
soil water through the profile to
be most rapid
sandy loam in upper
layers with layer of
coarse gravel
underneath
31.
the following are acid cations
abundant in a pH 4.5 soil
aluminum, hydrogen
32.
the following buffer compounds
tend to mantain an alkaline soil
ph
calcium and sodium
carbonates
33.
the following buffer compound
tends to maintain an acid soil pH
carbonic acid and
humus
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
fungal hyphae have an
important influence on soil
structure because they
help flocculate the soil
colloids, stabilize macro
aggregates, are active in the
formation of soils crusts,
create large channels that
enhance water flow and
aeration
a grayish low chroma soil
located on concave valley
landscape position is most
likely to be
need anser
highest cation exchange
capacity
humus
a homeowner in CA
attempted to grow azaleas in
a well drained soil ph 7.5 but
the plants were stunted and
the leaves were yellow
Fe deficiency
humus is an important soil
colloid. It differs from 2:1
type minerals in all but one
of following characteristics
influence of isomorphous
substitution
if a dry soil high in certain
types of ___is moistened it is
likely to swell up with
enough enough force to
crack pavements and building
foundations
clay
if you want to quickly in just
a few days increase the pH
of a soil from 5.5 to 7 which
of the following would you
use
calcite limestone
If you were looking for a soil
with high cation exchange
capacity and were not
concerned with the soils
physical properties which
would not fit your needs
vertisol
If you were seeking a soil
colloid with a high capacity to
adsorb cationic pollutants,
but also with a consistent
capacity to do so even as the
pH varied form 4.0-7.5
montmorillonite
in an acid mineral soil
derived from granite, the
following cations will likely
be deficient
magnesium, calcium
in an acid mineral soil
derived from granite the
following cations will likely
be present
hydrogen, K
45.
in an acid, organic soil, the following
cations will likely be present
need answer
46.
in an acid ph 4.5 mineral soil derived
from granite the following soluble
cations will likely be present
hydrogen,
aluminum
47.
in an alkaline mineral soil derived from
limestone the following soluble cations
will likely be present:
calcium,
magnesium,
potassium
48.
in an alkaline soil derived from
dolomite, the following cations will
likely be present
magnesium,
calcium
49.
in many soil profiles, the subsoil is high
in clay but is also quite permeable to
percolating water. Why?
Prismatic
structure may be
well developed
50.
in order to convert an acid organic ph 4
soil into a productive 6 ag soil the best
reclamation recommendation would be
to
add lime
thoroughly and
incorporate it
into the upper
food of soil
51.
in order to convert an acid ph 4 soil
into a productive pH 6.5 ag soil the best
reclamation recommendation would be
to
add lime and
thoroughly
incorporate it
into the soil
52.
in order to convert an alkaline 9.5 soil
into a productive ag soil the best
reclamation recommendation would be
to
add phosphoric
acid, sulfur and
organic matter to
the topsoil and
incorporate it
53.
in order to convert an alkaline mineral
ph 9 into a productive ag soil 6.5 the
best reclamation recommendation
would be to
add sulfuric acid
and organic
matter to the
topsoil and
thoroughly
incorporate it
54.
irrigation of ag soils in san joaquin
valley results in
increased
humidity and
moisture levels in
the atmosphere
55.
land leveling of ag soils of san joaquin
valley causes
need answer
56.
A landscape contractor wants to
change the texture of a silt loam soil to
meet the specifications for a loam he
would most likely be adding__to the soil
and mixing it well
Sand
57.
large areas of western fresno co are
subject to subsidence due to __
need answer
58.
Least apt silicate clay to be formed
from the alteration of primary minerals
chlorite
a loamy sand soil high
in o.m in a redwood
forest, will have__in its
epipedon
a low percent basic cation
saturation
74.
the optimum pH range for acid
loving azaleas and pine trees is
4.5-6
75.
optimum ph range for max plant
nutrient availabilty is
6.5-7
60.
many ag soils in the sw
san joaquin valley
have____in their topsoils
sodium carbonate and chloride
salts
76.
organic matter decomposition
within the sac delta islands causes
subsidence of the
land and destruction
of human structures
61.
many ag soils in the
tulare lake basin
have__in their subsoils
sodium carbonate and chloride
salts
77.
the osmotic potential would likely
be lowest in this soil order
spodosol
62.
material which is most
often added to acid
soils to raise the ph is
calcium carbonate
78.
need to answer
63.
matric potential of soil
water is
generally higher than that of pure
water outside the soil
the percentage of which soil
components represent the
minimum information necessary in
order to determine the textural
class of a soil
79.
64.
mechanical ripping of
soil hardpans in eastern
San Joaquin valley
causes
improved rooting depths for
perennial tree crops
percent porosity and soil bulk
density are related. An increase in
porosity will result in
a decrease in bulk
density
80.
iron
the more vermiculite
clay and o.m. a soil has
the greater its
cation exchange capacity
Phosphorous availability is very low
in most strongly acid soils because
of its reactions with
81.
physical properties of soils
The more vermiculite
clay an om a soil has,
the greater its
percent basic cation saturation
structure, bulk density,
temp, water holding
capacity
82.
plant roots obtain access to soil
water by
67.
the most common acid
found in all A horizons
is
carbonic acid
roots extend into
moist soil area and
water flows to the
roots by capillarity
83.
the negative charges
associated with
smectite clay crystals
are due mostly to
isomorphous substitution of Mg
for Al in the octahedral sheet
the potential soil acidity is defined
as___
need answer
68.
84.
need to answer
nonsaline alkaline soils
are characterized by
low levels of available iron, high
levels of molybdenum, low levels
of available manganese, low
levels of boron
practices that add organic matter
and reduce tillage can be expected
to most significantly increase___in
the soil
85.
Practice useful in stabilizing surface
soil structure
70.
Not a physical property
of soil
cation exchange capacity
use of organic
mulches, use of green
manure crops,
growing grass sod,
minimizing tillage
71.
once can decrease the
soil bulk density by
adding___to the topsoil
need answer
86.
precipitation falling in excess of the
soil infiltration rate is lost by
surface runoff
87.
one can increase the
soil basic cation
saturation % by adding
calcite and dolomite
a reddish brown soil located on an
upland landscape position is
need answer
72.
88.
the seasonably high watertable of a
soil determines its
need answer
one can increase the
soil bulk density by
adding___to the topsoil
granitic sand and gravel
89.
soil buffering capacity can be
increased by adding__ to the
topsoil
om and calcite
59.
65.
66.
69.
73.
90.
soil color is a result of
mineral
composition
and organic
matter
content
91.
Soil colors are scientifically described
by___color designations such as 10YR3/4
munsell
92.
soil has the lowest total water holding cap
sand
93.
a soil having a large proportion of
macropores will differ from a soil having a
large proportion of micropores the soil with
more macropores will have a
rapid
infiltration
rate and
low water
holding
capacity
a soil having a large proportion of
micropores will differ from a soil having a
large proportion of macropores. the soil with
more macropores will have a
slower
infiltration
rate and
higher
water
holding
capacity
94.
95.
96.
97.
98.
104.
soils of which of the following
textures can absorb and hold the
greatest amount of air pollutants
along a heavily traveled highway
need answer
105.
soils rich in which type of clay would
provide the most troublesome site
on which to build a home
smectite
106.
soil textural class that you would
expect to have the lowest cation
exchange capacity
loamy silt
107.
a soil that has a high amount of
expansive montmorillonite clay will
be composed of abundant
montmorillonite and
vermiculite
108.
soil wiht mostly permanent negative
charges would contain high amounts
of
vermiculite and
montmorillonite
109.
A soil with a bulk density equal to
.35 g/cm3 is most likely what type of
soil
need to answer
110.
percolation
through the
subsoil
a soil with a high CEC will likely be
composed of high amounts of
vermiculite and
humus
111.
a soil with a low buffering capacity
will not contain abundant
clay and organic
matter
a soil low in organic matter is most likely to
be deficient in which essential element for
plant growth
nitrogen
112.
a soil with a low cec will likely be
composed of high amounts of
quartz sand and
gravel
113.
soil ph is a measure of
hydrogen
ions in the
soil solution
a soil with low buffering capacity will
contain abundant
quartz sand and
gravel
114.
cation exchange
capacity
hydrogen
and
ammonium
in fertilizer
a soil with no montmorillonite clay
and low organic matter content will
have a low
115.
some soil colloids exhibit positive
charges under highly acid conditions
what are these charges likely due
the adsorption of
Al3+ ions on the
colloid
the soil infiltration rate is similar to
soil pH is changed rapidly by adding
99.
the soil pH will be ____after 10 years as a
result of adding ammonium-nitrogen
fertilizers to sandy soils
decreased
116.
a sticky-putty like feel indicates a
high percentage of which soil
separate
clay
100.
the soil pH will be__ after 10 years as a
result of adding calcium carbonate to sandy
soils
need
answer
117.
subsidence soils in the western
fresno co area is causing
cracks to form in the
walls of the ca
aqueduct
101.
soils can be acidified by incorporating ___to
the topsoil
organic
matter and
sulfur
118.
subsoil drainage systems in ag soils
help to
need answer
Soils high in organic matter commonly hold
more available water than comparable soils
with lower organic matter level. This is most
likely due to what characteristics of high
o.m. soils
higher field
capacity
119.
102.
The swelling/shrinking tendency of
some silicate minerals is due
primarily to
the movement of
water molecules in
and out of the
interlayers of the
crystals
the soils near mount lassen are weathered
from
volcanic
ash and
igneous
rocks
120.
textural class with highest cation
exchange capacity
silty clay
103.
121.
texture describes the ____of particles in a soil
sizes
122.
texture with the highest cation exchange capacity assuming that they all have the
same organic matter content
clay loam
123.
unsaturated water flow
is faster than saturated flow
124.
using a textural triangle chart it can be determined that a soil with 45% sand and
20% clay belongs to the __textural class
loam
125.
vernal pools are
depressional areas that form seasonal
wetlands due to water ponding
126.
a well drained soil under a rain forest in Brazil contains significant amounts of
silicate clay most apt to be
kaolinite
127.
Which of the following human actions is most apt to result in a long term
increase in soil pH
irrigation with high sodium salt containing
waters
128.
which of the following is not a textural class name
sandy silt
129.
which of the following soils would have the highest total water holding capacity
need answer
130.
Which of these essential elements is it most likely to be toxic to plants in a soil
at pH 5
manganese
131.
which type of soil structure is typically found in surface soil A horizon
granular
132.
which type of structure is typically found in sodium rich sub surface horizons
columnar
Soils Lab Final
Study online at quizlet.com/_10vtsz
1.
2.
3.
4.
5.
Aggregate shapes
A high quality soil
has adequate...
Alfisols
Andisols
An undisturbed
mineral soil
contains...
Aridisols
Bulk density =
- Crumb: often found near roots, resembles cookie crumbs
- Granular: similar to crumb, but smaller
- Blocky: irregular blocks 1.5-5cm in diameter with sharp angles
- Sub-angular blocky: edges more rounded
- Prismatic: vertical columns of soil, usually in lower horizons
- Columnar: vertical columns with a salt cap
- Platy: thin, flat horizontal planes
Moisture, nutrient holding capacity, drainage, temperature, nutrients, pH, and biological activity.
Clay or natric sub-surface horizons
Volcanic origin
~45% mineral matter, 5% OM, 50% pore space (can be occupied by water or air depending on soil
moisture content)
Dry soil
7.
The mass or weight of an undisturbed soil sample per unit of volume.
BD = oven dry soil weight (grams)/volume of soil, solids, and pores (cm³)
Usually range from 1.1-1.5 g/cm³
8. Carbonation
Carbon dioxide reacts with water, producing carbonic acid, which then dissolves the calcium carbonate
in the soil.
CO₂+H₂O→H₂CO₃
H₂CO₃ + CaCO₃→Ca²⁺ + 2HCO₃⁻
9. Carbon
Capturing of carbon in the soil by increasing OM content. Helps decrease CO₂ content in the
sequestration
atmosphere.
10. Cation exchange
- Accounts for many important reactions in soil
- Occurs b/c soil colloids are negatively charged, so attract positively charged ions (H, Ca, [acid
forming] Mg, K, Na, Al [base forming])
- Called cation exchange because cations in soil solution can exchange with cations absorbed on soil
colloids
- Charge density influences how tightly cations are held by colloids-- if held tightly, colloid's whole
negative charge is neutralized, making colloids stick together/flocculate. If loosely held, colloid charge
isn't completely neutralized and colloids disperse.
- Given in cmolc kg⁻¹ or meq/100g
11. CEC application
1. If a soil is acid and the pH needs to be raised, the H⁺ on the exchange complex needs to be
examples
replaced with calcium. Amount of calcium needed depends on CEC.
2. If nitrogen is applied to soil as NH⁴⁺, nitrogen will have less chance of leaching if there's sufficient
CEC.
12. C:N ratio
If C:N is high, microorganisms will take mineralized N from soil to meet their needs (immobilization).
13. Decomposition
The breakdown of complex organic material into its constituent parts. Ex: Glucose breakdown to
carbon dioxide and water with energy release.
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy
14. Density =
Mass per unit volume.
D = m/v
15. Endorheic basin
A basin that doesn't drain, like the Great Basin (from Sierras to Wasatch, portions of
Idaho/Oregon/Arizona)
16. Entisol
Recent, little profile development
17. Evapotranspiration
Evaporation (loss of water from soil) plus transpiration (loss of water from plants.
18. Fertilizer label
30-10-10 is 30% N, 10% P₂O₅, 10% K₂O.
6.
19.
Fertilizer stats
20.
Fine-grained mica/illite
21.
Five factors of soil
formation
Gelisols
23. Gravimetric water content
22.
Histosols
25. How did peat soils near
Utah Lake form?
26. Hydration
24.
27.
Hydrolysis
Inceptisols
29. Is it a good idea to add
sand to hard-to-manage
soil with a high clay
content?
30. Kaolinite
28.
- Commercial fertilizer use has increased dramatically during last half of 1900s, resulting in
tremendous crop yields.
- Often applied at rates significantly higher than needed by growing plants, leading to
concerns about environmental degradation.
2:1 Si:Al sheet ratio. Potassium between sheets holds them together. Medium surface area,
medium shrink-swell, medium CEC. Found in areas with minimal weathering.
Parent material
Climate
Living organisms
Topography
Times
Affect color, particle size, pH, pore space, depth, horizon development.
Permafrost
Most accurate way to measure soil moisture-- taking a sample of known volume and
weighing wet then dry to determine moisture percentage on a mass basis. Mass of water is
divided by the weight of the dry solid material, so dry weight (not wet weight) basis.
Peat or bog, >20% organic matter
Large amounts of vegetation grew and got dropped in wet conditions, making soils OM high
in a high water table.
Intact water molecules bind to a mineral.
2Fe₂O₃ + 3H₂O→2Fe₂O₃ - 3H₂O
Water molecules spit into their hydrogen and hydroxyl components. Hydrogen replaces a
cation from mineral surface.
KAlSi₃O₈ + H₂O→HAlS₃O₈ + K⁺ + OH⁻
Embryonic soil, acid
No. Adding sand may form a concrete-like substance in the soil.
33.
1:1 Si:Al sheet ratio. Low surface area, low shrink-swell, low CEC. Found in subtropical areas
with severe weathering.
Primary - N, P, K
Secondary - Ca, Mg, S
Found in higher % levels than micronutrients. Primarily deficient, often require fertilizer
addition. N most commonly deficient (half of all fertilizer sales worldwide)
Macro pores allow for free drainage of water and are filled with air in unsaturated conditions.
Micro pores hold most plant-available moisture, which remains in the soil after gravitational
water has been removed.
Macro pores are destroyed when soil is compacted, making it hard for water to drain and for
roots to penetrate soil layers.
Sedimentary rock-- limestone, sandstone, shale
35.
Sum of anabolism (removal of water from molecules in order to grow larger molecules like
starches) and catabolism (water used to break bonds to generate smaller molecules like
glucose). Water necessary for both processes.
Cl, Zn, Fe, Mn, Cu, B, Mo, Ni, Co
31.
32.
Macronutrient essential
plant nutrients
Macro vs. micro pores
Major parent material at
Rock Canyon
34. Metabolism
Micronutrient essential
plant nutrients
% moisture by
volume =
37. % moisture by
weight =
38. Mollisols
39. N is needed for...
36.
40.
Nitrogen cycle
[(wet weight - dry weight)/dry weight) *bulk density *100
[(wet weight - dry weight)/dry weight] *100
Dark, highly productive, >50% base saturation
Amino acids, proteins, enzymes, ADP/ATP, chlorophyll development and function in plants (chlorosis
caused when deficient).
Plants require inorganic forms (NH₄⁺ and NO₃⁻) for uptake.
N fixation - mineralization - ammonia volatilization - nitrification - denitrification.
N₂→Organic N (R-NH₂)→Soil N→NH₄⁺→NH₃→NO₂⁻→NO₃⁻→NO₂⁻→N₂O→N₂
Carbon, oxygen, hydrogen
Come primarily from air and water.
Non-mineral
essential plant
nutrients
42. N
(Yield goal * Crop factor) - (Surface soil N + Subsoil N) - Legume credits - Manure - Water
recommendation
=
43. OM in soil
- Usually less than 5% of mineral soils
- Involved with nutrient availability, CEC, buffering capacity, aggregate stability, water retention,
pesticide sorption.
- Originates with plant tissue, which becomes humus (most active OM portion, accounts for much of OM
CEC)
- High OM = high fertility. OM provides lots of reserve nitrogen, so as it decomposes N is released (25%/year)
- OM increases aggregate stability, so also drainage/aeration/plant growth.
- OM increases water holding capacity, so less frequent irrigation but better drainage.
44. OxidationElectron transfer from one compound to another. LEO GER.
reduction
2FeO + 2H₂O → 2FeOOH + 2H⁺
45. Oxisols
Highly weathered, tropical soil
46. Ox-redux
Electron donor is oxidized, electron acceptor is reduced. Oxidation number increases for oxidized
elements and decreases for reduced elements. Oxidized compounds are low-energy compounds, while
reduced compounds are high-energy compounds.
47. Particle density
The weight of the soil divided by the particle volume.
=
PD = soil weight (g)/volume of soil solids (cm³)
Generally assumed to be 2.65g/cm³ (quartz density).
48. Phases of soil
1. Take soil sample
testing program 2. Laboratory analysis
3. Interpretation, recommendation formation
49. Phosphorus test
- Bray P1: Used for neutral, acid pH soils, non-calcareous alkaline soils. Uses acidic NH₄F as extracting
types
solution.
- Olsen: used for calcareous soils. Uses sodium bicarbonate as extracting solution.
- Mehlich III: Like Bray P1, but more acidic and buffered against pH change. Includes a chelate (EDTA) to
simultaneously extract micronutrients.
50. Plant available
Moisture between field capacity and the permanent wilting point-- approx. half of water in soil, while
water
the rest is held too tightly by capillary forces in the soil for plants to take up. Plants can become stressed
by permanent damage before whole PAW is used-- called depletable water, range to stay in to maximize
growth.
51. % pore space =
1 - (bulk density/particle density) *100
41.
52.
53.
54.
55.
Residue factors
Saline/sodic soil
reclamation
Salinity and sodicity
problems
Salinity/sodicity
determination
1. Having an energy source or residue available
2. Nutrient content of the residue, mainly C:N ratio (if N content low, decomp is slowed)
3. Residue particle size (larger = lower surface area, so less decomp)
4. Incorporation of residue into soil (decomp is much faster if residue is in soil as opposed to
left on top).
First make sure soil is well drained. If a sodic soil, then add soluble calcium (commonly gypsum,
CaSO₄-- poorly soluble sources like CaCO₃ won't dissolve at high pH) to replace sodium on
exchange sites (will cause clay to flocculate). Then leach soil to remove salts for saline soil and
sodium specifically for sodic soil (must use low-salt irrigation water).
Problems exist in dry regions because there's not enough moisture to leach sodium and other
salts from the soil. Usually originate from salt-bearing parent material or high-salt irrigation
water (all irrigation water has some salts). Water tables near soil surfaces also tend to evaporate
and leave behind surface salt.
1. pH
2. Electrical conductivity (EC) of saturated paste extract. Water is pulled from saturated paste
and EC determined, and the more salt present = greater electrical conductivity of solution.
3. Exchangeable sodium percentage (ESP): Measures how much of the CEC is taken up by
sodium. Accurate ESP determination requires CEC determination, quantification of cations on
exchange complexes, and calculation of percent Na on exchange sites. Most labs just quantify
cations on exchange complexes and estimate CEC from that. If Na% is elevated around 15%, the
sodium absorption ratio is also tested.
pH EC ESP SAR
Normal <8.5 <4.0 <15 <13
Saline <8.5 >4.0 <15 <13
Sodic >8.5 <4.0 >15 >13
Sa-so varies >4.0 >15 >13
56. Salts
Mineral substances that form from the reaction of an acid and a base. Composed of related
numbers of cationic bases and anions, like Ca²⁺ and Cl₂⁻.
57. Six horizons
O - Organic matter/thatch located on soil surface above the mineral horizons.
A - Mineral horizon on soil profile surface or just below O, called topsoil. Dark-colored because
this is where most biological activity occurs, so OM accumulates. Most fertile horizon.
E - Lighter in color, where eluviation of lots of clay/OM has taken place. Often found in high
rainfall climates under forest vegetation, often absent in other conditions.
B - Zone of accumulation or illuviation. Generally has accumulation of iron, clay, sometimes
calcium and OM. Well-developed B horizon indicates the soil is relatively old.
C - Less weathered than A/B/E. Layers of unconsolidated material, either unaltered material
transported through wind/water erosion, or bedrock that has weathered in place.
R - Unweathered bedrock material.
58. Smectite/montmorillinite
2:1 Si:Al sheet ratio. No potassium between layers to hold them together. High surface area,
high shrink-swell, high CEC. Found in temperate zones like the midwestern US. Usually the
most productive.
59. Soil cations
Ca>Mg>K>Na are exchangeable bases and nutrients.
H cation is found in greater concentration than bases in highly acidic soils. Lower than
exchangeable bases in alkaline soils.
Al is also a cation, but isn't a nutrient (often toxic in acidic soils).
60. Soil colloids
- Smallest soil particles
- Will remain suspended in water
- Not just very small rock, but chemically changed-- considered secondary minerals
- Negatively charged-- attract cations and water
- Include clay and humus
1. Temperature: if too hot or too cold, microbe growth is inhibited, decomp is slowed. Best
between 25 and 35°C.
2. Moisture: If low, microbe growth is slowed. If too high, aerobic organisms inhibited.
3. Chemical composition: Organisms require the same essential nutrients as plants, so if one
is deficient growth is slowed.
62. Soil formation process
Soil begins to develop from parent material through physical weathering, which breaks up
larger particles w/o changing chem composition. Then, there are five categories of chemical
weathering: Solution, hydration, hydrolysis, carbonation, ox-redux.
63. Soil OM management
- More OM almost always beneficial, but not always easy/economical
- No-till, addition of composts or green manure crop.
64. Soil salinity
Soluble salt in soil solution-- Ca, Mg, K, Na cations, Cl, SO₄, and HCO₃ anions. As soil solution
salt increases, so does osmotic pressure, so at high levels plant roots can't get water quickly
enough to survive.
65. Soil sodicity
Sodium has a large water hull/low charge density and isn't held tightly by colloids, so doesn't
totally neutralize negative charge and causes colloids/clay to disperse. Clay dispersion
restricts water infiltration, seedling emergence, root penetration.
66. Soil test
- Goal of extraction/chem analysis in lab is to estimate the portion of the nutrient that will
goal/design/interpretation correlate with the amount a plant can obtain.
- Most designed to imitate a portion of plant's mechanisms for nutrient uptake. Extractants
contain ions that replace nutrient in the soil, or they precipitate the element associated with
the nutrient.
- Result is determined as low, medium, or high, with inverse fertilizer recommendations.
67. Soil testing is used in...
Agriculture, horticulture/landscape management, engineering, range, forest, environmental
science. Determines nutrient deficiencies, toxicity hazards, plant nutrient supplying capacity.
68. Soil texture and water
Finer-textured soils have higher water holding capacities, and coarser textured soils have
larger pore place, which allows water to travel through it more quickly.
69. Soil texture determination
1. Feel soil when moist (sand gritty, silt smooth, clay sticky)
methods
2. Hydrometer method
3. Pipette method
70. Soil texture influences...
Water holding capacity, nutrient holding capacity, aeration, drainage, infiltration, specific
surface area.
71. Soil texture sizes
Sand: 2.0-0.05mm
Silt: 0.05-0.002mm
Clay: <.002mm
72. Soil & tissue sampling
- Take unique samples for unique areas
- Needed: Sample bags, clean plastic bucket, soil probe, and/or other sampling device
(shears)
- Bags should be cloth so soil can breathe. Paper bags are okay if soil isn't wet. Plastic bags
okay if soil is at lab within 24 hrs and kept cool.
- Surface samples should be taken to depth of where most roots are located.Turf, pasture,
etc. about 4 in., crops, vegetables, shrubs, flower gardens about 8-12 in (tillage depth), trees
2-3 ft.
- Collect 8-20 cores from sample area (larger area = more samples). Walk in a zig-zag
pattern, collecting randomly.
- Mix soil with clean hands/gloves (no fertilizer dust). No rubber or metal. Stainless steel
okay.
- Keep samples cool or dried at room temperature with a low-setting fan, Don't get them
contaminated.
61.
Soil factors
73.
74.
Soil water
levels
Soil water
movement
% solid space
=
76. Solution
75.
Spodisols
78. Stokes Law
77.
The most
productive
soils in the
world are in...
80. Three factors
that led to
topography
of Utah Valley
81. Three phases
in soil
82. Transport
mechanisms
79.
Types of clay
(mineral
colloids)
84. Ultisols
85. Vertisols
86. Volume
determination
methods
83.
When soil is saturated (all pores filled with water), water drains out initially by force of water (called
gravitational water). Remaining water is held by adhesion and cohesion, and soil is now at field capacity
(upper level of plant-available moisture at -1/3 bar). As field dries (plant uptake, evaporation), a point is
reached where plants can't get water, called permanent wilting point (lower end of plant-available moisture
at -15 bar). Water remaining after the soil is dry is the hygroscopic moisture (up to -10,000 bar).
- Infiltration: movement of water into the soil
- Percolation: movement of water through the soil
- Permeability: determines percolation
Coarse textured soils allow faster hydraulic conductivity (water movement) unless compacted (common in
sandy loam soils). Layers of different textures or materials (OM) restrict/slow water movement.
(bulk density/particle density) *100
Cation and anion of a molecule dissociate. Ex: dissolving sodium chloride in water.
NaCl→Na + Cl
High Fe and Al oxides
Particles in water settle at a velocity proportional to their size-- the bigger they are, the faster they fall.
Simplified equation: V = kd², where V = velocity, d = particle diameter, and k = constant.
Temperate climates. Warm moist climates have too much leaching/weathering, and cold climates have
decreased production.
- Plate tectonics: subduction formed mountains
- Ancient ocean
- Parent material: Lots of sedimentary rock weathered down to form soil
Water, air, solids
Gravity - colluvium
Wind - eolian
Water
- Marine sediments
- Non-marine sediments-- lacustrine, fluvial, glacial till, alluvium
Volcanic
Cyrstalline makeup, or ratio of silicon (tetrahedral) sheets to aluminum (octahedral) sheets determines kind
of clay-- kaolinite, fine-grained mica/illite, smectite/montmorillinite.
Ultimate weather, low base saturation
High swelling clay
1. Cup-cutter method (push container with known volume into soil-- can be inaccurate b/c soil is
compacted as container is pushed in)
2. Archimedes Principle: an object placed in water is buoyed up by force = to weight of displaced water.
Applied by weighing an aggregate in air, then in water-- the difference in weight is the force of the water
pushing against the aggregate. The weight of the displaced water = volume of displaced water = aggregate
volume, since 1cm³ water = 1 g water.
87. Volumetric
Volume of water divided by entire volume of the soil-- this one includes air space. Most easily and
water content commonly determined by multiplying gravimetric water content by bulk density. Can also be estimated by
soil moisture probes.
89.
Water formation
Water need/use
90.
Water stats
88.
99.
What effect does tilling have on
bulk density in short and long
term?
What is the best material to
decrease bulk density?
What two constituents give soil
its color?
Which horizon usually forms
first from parent material?
Which textural class retains the
fewest nutrients?
Which textural class would be
most desirable for a home
garden?
Why are soils at the mouth of a
canyon coarse-textured while
those in the valley floor are
fine-textured?
Why does calcium flocculate
clay while sodium disperses
clay?
Why is high CEC desirable?
100.
Why is Utah Lake so dirty?
91.
92.
93.
94.
95.
96.
97.
98.
101.
You add compost to your
flowers and they all turn yellow.
Why?
H⁺ and OH⁻ neutralize one another to form water at a pH of 7, or neutral.
1 billion people lack safe water access, 2.5 billion lack adequate sanitation access. By
2025 more than half world population may be facing water vulnerability, by 2030 water
demand may exceed supply by 50% in developing regions. 70% freshwater used by
humans is for agriculture.
71% Earth's surface
96.5% in oceans
1.7% in groundwater
1.7% in glaciers, Antarctic/Greenlandic ice caps
0.001% in air as vapor, clouds
Tiny fraction in other water bodies
2.5% freshwater, less than 0.3% of which is in rivers/lakes/atmosphere, and 0.003% in
biological bodies/manufactured products
Short - loosens soil
Long - soil structure is destroyed, compacted
Organic matter (very low density)
Organic matter and iron.
A
Sand, because it has a high draining capacity that results in nutrient leaching.
Loam. It would have enough (but not too much clay) to retain ideal water and nutrient
levels.
The larger particles in the water that formed the canyon got dropped first, while finer
particles got carried farther into the valley before settling out.
Calcium has a higher charge density, so it's held tightly to colloids and neutralizes the
whole charge, causing colloids/clay to flocculate. Sodium's not held as tightly, so whole
charge isn't neutralized and the colloids/clay disperse.
- High CEC soils can hold more nutrients for plant uptake
- Regulate pH more effectively.
More clay is great for holding nutrients, more OM best.
- Algae blooms: nutrient pollution
- Invasive species: carp plough up the bottom, kill vegetation, stir up sediment
- Shallow: Wind kicks everything up
- Other pollution
...
Soil Mechanics Final
Study online at quizlet.com/_5r5hja
1.
Another name for the GWT
Phreatic surface
2.
ASTM test specification says that
all the soil of a sample being
tested in the lab Proctor test must
pass through a No. 4 sieve if the 4inch diameter compaction mold is
to be used. If larger soil particles
are present, what mold size must
be used?
6 inch
Briefly explain the fundamental
reason that causes there to
eventually be an increase of shear
strength of a normally
consolidated clay soil which is
below a newly constructed
embankment, the increase
happening slowly with time after
the embankment is constructed
The water leaves the
clay at a slow rate so
the shear strength will
increase when the pore
water pressure
decreases
4.
An example of a metamorphic
rock
Schist
5.
An example of an igneousextrusive rock
Basalt
6.
An example of a sedimentarychemical rock
Dolomite
7.
An example of igneous-intrusive
rock
Granite
8.
An example of sedimentaryclastic rock
Conglomerate
9.
Explain in a brief statement, what
happens initially to the effective
vertical stress in a saturated and
normally consolidated and clay
soil stratum, when loaded by a
new 25-ft high embankment that is
quickly placed over a clay soil
deposit
Initially the effective
vertical stress stays the
same because it takes
time for the excess
water pressure to leach
out of the clay. When
this happens, the
effective vertical stress
will increase slowly
Explain in terms of internal
particle structure of the clay, why
the slope of the graph of e vs log
p becomes steep when effective
stress on the clay soil exceeds the
max past pressure?
Particle bonds break
3.
10.
11.
Explain what happens in the clay soil that
would cause several inches of settlement
due to compression of the soft normally
consolidated clay when there is a
lowering of the groundwater table from
Level A to Level B. Assume that the clay
is saturated and remains submerged
below groundwater level
Lowering the
GWT would
cause
settlement
12.
Explain why the Ch value of a clay soil is
usually 2.0-5.0 greater than the value of
the clay soil's Cv parameter
Clays are
naturally laid
horizontally so
water flows
faster
horizontally
causing Ch to
be greater than
Cv
13.
Explain why the permeability of clay soil
is so slow and seemingly not affected by
the total volume of voids in the soil, even
though clay has 2 to 5 times the voids of
sand
Clay's voids are
very small so
water can't
pass though
very quickly
and water
adhesives to
clay due to the
diffuse double
layer
14.
If a sand soil has a void ratio value of
0.30, then what term best describes its
density?
Very dense
15.
If the groundwater table is originally at
ground surface and then drops to be 15 ft
below the ground surface, what is the
effect on effective vertical stress in the
ground?
Increased
16.
If the unconfined compressive strength of
a clay sample is 1800 psf, what will be the
cohesion of the clay when it is tested in
unconfined compression?
900 psf
17.
In a clay consolidation test, what is the
size (diameter and height ) of the usual
clay sample that is tested in the onedimensional compression test?
2.5 in, 1 in
18.
In a sand soil, what is the 4-word name
for the parameter that is used to define
the sand's shear strength, which also is the
inclination of the shear strength
envelope?
Angle of
internal friction
19.
In the equation for clayey sand soil, which
part applied for the clay component of
the soil?
Capp
20.
In the USCS system, write the three
words that describe a soil classified as
ML soil?
Low plasticity
silt
21.
Limestone is calcium carbonate, and it is
easily weathered by acid rain. What is
the name of the other carbonate rock
type that has magnesium, which makes it
more resistant to weathering acid rain?
Dolomite
List 4 of the 8 major different types of
minerals from which various types of
rocks formed
Quartz, Mica,
Feldspars,
Ferro-mags, Iron
Oxides, Sulfates
22.
23.
List the 4 conditions necessary for
Liquefaction to occur in a natural sand
deposit
Loose soil, fine
sand, below
GWT,
earthquakes
24.
List the three most common clay
minerals that were discussed in class
Montmorillonite,
Kaolinite, Illite
25.
Make a sketch to the right of the soil
fabric that results from compacting clay
soil that is dry of optimum w.c.
Particles are
more spread out.
Higher
permeability
and the particles
stick together
better
26.
Name of the groundwater stratum
overlain by a clay layer and under
pressure
Artesian
27.
Name of the soil stratum through which
groundwater will not flow freely
Aquiclude
28.
Name of the zone of soil above the GWT
Vadose
29.
The plastic limit test involves rolling out
a soil thread until it just breaks into
smaller pieces when thread is what
diameter?
1/8 inch
30.
A soil with 4% fines, and 51% passing the
No. 4 sieve, with a Cu=5.2 and Cc=1.5 will
be classified as which of the following?
GW
31.
TF: A clay soil is considered to be at its
liquid limit when the slot closes for 1/2
inch of its length at 35 drops of the brass
cup
False. 25 drops
32.
TF: After a new large wide area fill has been
placed over a soft soil layer that has sand
above and below, the excess pore water
pressure in the clay caused by the fill
placement dissipates quickly at the top and
bottom of the clay stratum, but very slowly
in the middle of the clay stratum
True
33.
TF: All the clay soils exhibit the same
behavior and shear strength when at their
Liquid Limit, even if one clay has LL=130%
and another clay has LL=25%
True
34.
TF: A surcharge load is usually a larger
thickness of embankment fill that is used to
over-stress the soft clay layer so that the
rate of consolidation is speeded up, which
essentially means that the extra load caused
the Cv value to increase
False. It
doesn't
cause the
Cv value to
increase
35.
TF: Boussinesq developed his basic equation
in 1885 for the purpose of determining the
increase in vertical stress in the ground due
to a building load or embankment or other
applied loading?
False. It is
the basis for
most
geotechnical
solutions for
determining
the increase
36.
TF: Clay soils usually have a void ratio that is
greater than 1.0, but not sand.
True
37.
TF: If a clay soil deposit currently has an
effective vertical stress that is less than
maximum past pressure found in the
consolidation test, then the clay has an OCR
< 1.0
False.
Smaller
stresses
have an
OCR > 1
38.
TF: If in a C-U triaxail test on stiff clay,
confining pressure = 10 psi, and the axial
stress = 30 psi, and the pore water pressure
= 5 psi at failure, then the deviator stress at
failure was 25 psi
False
39.
TF: In a C-U triaxial test, the Su of an overconsolidated clay will only increase when
the effective confining pressure is raised to
a pressure greater than the maximum
effective vertical stress that existed in the
ground when the sample was retrieved by
using the Shelby tube sampler during
subsurface exploration
True
40.
TF: In the formation of igneous rock, rapid
cooling of molten magma results in a large
and coarse grained mineral structure and
texture
False. It's
slow
cooling
41.
TF: In working with a "performance"
specification, only the required percent
compaction is specified, but often the
allowable range of moisture content is
also specified
True
42.
TF: The diameter of the Mohr's circle
graph from a triaxail test represents the
deviator stress, and equals to the
maximum shear strength of the clay,
regardless of the internal pore water
pressure
False. The
maximum shear
strength equals
to its radius
TF: The diffuse double layer is the basic
structure of each clay particle, and
these clay particle diffuse double
layers are the 2 different mineral
sheets bonded together
False. The diffuse
double layer is
the region of
attracted positive
ions in solution
and the
negatively
charged surface
of the clay
43.
44.
TF: The fundamental property of clay
soil that is the basis for its undrained
shear strength is actually apparent
friction
False. Cohesion
45.
TF: The in-field pumping test is the best
way to determine the overall
permeability of the overall soil deposit
True
46.
TF: The initial indrained shear strength
of stiff clay soil below the bottom of a
deep excavation is much greater than
the drained shear strength that will
develop after many months of
unloaded condition caused by
excavation
True
47.
TF: The one physical aspect of a clay
soil that causes consolidation
compression of clay soils to usually be
much greater than compression of sand
soil, even under the same magnitude of
loading, is the fact that clay has a much
larger initial void ratio than does sand
True
48.
TF: The optimum moisture content of a
clay soil is usually substantially lower
than that for a well graded granular soil
False. Clay is
substantially
higher than a
well graded
granular soil
49.
TF: The rate at which clay consolidates
in virgin compression is much slower
than when the clay compresses in
recompression
True
50.
TF: The sheepsfoot roller is most often
used to compact plastic clay soils
because the small peg-like feet apply
the high stresses needed to shear
through the clay and manipulate the clay
soils into denser condition
True
51.
TF: To achieve good degree of
compaction throughout the lift thickness
of a clayey soil, the thickness of loose
placed fill before compaction should not
exceed about 8-10 inches
True
52.
TF: When a load is first added to a
saturated soft clay soil, such as by
placement of a big highway
embankment, the added pressure is
initially carried by an increase in the soil
effective stress
False
53.
TF: When clean, well graded sand and
gravel soil is being compacted using a
vibratory smooth-drum roller, the
density test should be conducted at a
depth of at least 5-inches below the
compacted surface to avoid the
loosening that occurs due to the intense
vibrations the roller applies
True
54.
TF: When determining the value of Cv
from the results of a consolidation test,
the appropriate load increment to use
the dial vs log time data from is in the
over-consolidated stress range where
the initial vertical stress is smaller than
the preconsolidation pressure
False. The
appropriate
load to use
would be the
load that is
somewhat
higher than the
preconsolidation
pressure
55.
TF: When determining the value of the
Cc parameter from the e vs log pressure
graph that you get from a clay soil
consolidation test, and as you did in lab
last week, the Cc value is determined by
calculating the ratio (log(pressure2) log(pressure1))/ (e1-e2) for the virgin
compression part of the graph
False.
e2-e1/log
pressure2 - log
pressure1
56.
TF: When the loading on a clay soil is
rapidly increased, such as will happen
when a new embankment is built over a
soft clay deposit, the pore water
pressure in the clay will initially increase
a lot, however this increased pore
pressures causes an immediate decrease
in the clay's undrained shear strength
False
57.
TF: When the pore water pressure in
a sand soil is increased, it will cause
the available shear strength of the
sand to also be increased by a
similar amount
False. Pore water
pressure does not
effect shear strength
58.
TF: When the triaxial test is used to
determine the shear strength of a
sand soil, the value of the shear
strength parameter that is
determined in the trialaxial test will
be less than determined using direst
shear test on the same sand
True
TF: When using Mohr's Circle to
determine the shear strength of a
sand soil tested in triaxial
compression, the value of the major
principle stress is the confining
pressure, and the minor principle
stress is the axial stress.
False
TF: When you use the approximate 2
vert.:1 hor. method to find the stress
increase below a new foundation,
the stress increase that you calculate
under the center of the footing at
depth =B will be smaller than you
would calculate using the exact
method.
True
There are 2 graphs of horizontal
displacement verses shear stress that
are typical for a well-graded sand,
such as concrete sand, in direct shear
test for loose and dense sand as
indicated. Explain why the dense
sand curve eventually reached the
loose sand curve.
The dense sand
reaches the loose
sand because the
shearing of the sand
causes the particles
closest to the shear
to loosen up,
decreasing its shear
strength
There are 2 primary factors that
make plastic wick drains greatly
speed up the time for clay to
consolidate. You are to briefly
explain both factors in concise
statements
Hdr is decreased
Ch is used instead
of Cv which speeds
up time because
water flows better
with Ch
63.
What are examples of igneous
intrusive rock?
Diabase and granite
64.
What are the details of the Modified
Proctor compaction test that is done
in a lab? Hammer weight, Hammer
drop weight, number of soil layers,
number of drops on each layer
10 lb, 18 in, 5, 25
59.
60.
61.
62.
65.
What are the following details for the
Standard Penetration Test?
Hammer Weight, height of hammer
drop
140 lbs, 30 in
66.
What are the names of the two
different types of equipment that may
be installed to in completed boreholes
to determine groundwater level or
pressure in a soil deposit
Observation well
and piezometer
67.
What is the ASTM test designation
number and letter for performing the
standard penetration test?
D1587
68.
What is the ASTM test no. for modified
proctor compaction test?
1557
69.
What is the best compaction
equipment to use for a well-graded
coarse to fine sand with very little silt?
Smooth Steel
Drum Vibratory
Roller
70.
What is the best compaction
equipment to use for low plasticity
sandy clay soil with 25% silt?
Self-propelled
pad foot-type of
sheepsfoot roller
71.
What is the best compaction
equipment to use for non-plastic silty
sand without any gravel?
Pneumatic rubbertired roller with
water-filled
ballast tank
72.
What is the effect of increased
compactive effort, on the same soil?
That is, using the Modified Proctor test
instead of the Standard Proctor
Increased max dry
unit weight and
decreased
optimum moisture
content
73.
What is the effect on sand shear
strength that is caused by each of the
following changes in the granular soil
characteristics? Increased density,
decreased particle angularity, sand is
more well graded
Increased,
decreased,
increased
74.
What is the equation for the degree of
saturation?
s=(Vw/Vv)*100%
75.
What is the equation for the degree of
water content?
w=(Ww/Ws)*100%
76.
What is the equation for the specific
gravity?
s=
(Ws/(Vs*Gammaw)
77.
What is the equation used to
determine the hydraulic gradient?
i = delta(h)/L
78.
What is the full name of the quantity
that is determined from results of rock
coring, that has the initials R.Q.D?
Rock quality
designation
79.
What is the fundamental property of
sand soil that is the basis for its shear
strength?
Friction Strength
80.
What is the general name for wind-blown
soil deposits (used for both sand and
silt )?
Aeolian
81.
What is the grain size diameter (in mm)
that is the dividing line between fines
and sand particles sizes?
0.075
What is the meaning of the angle of
repose
The max angle
that a loose
soil can be
filled without
moving
horizontally
82.
What is the name of the device that is
used in soft clay below the bottom of the
borehole to determine the shear strength
of the soft clay directly during the field
exploration?
Vane shear
What is the name of the geotechnical
instrumentation that is installed in the
ground to measure the groundwater
pressure in a clay soil?
Piezometer
What is the name of the lab test that is
used to determine the grain size
distribution of the particles of fine soil,
that pass through the No. 200 sieve?
Hydrometer
Analysis
What is the name of the soil sampling
device that is used primarily to take
undisturbed sampled of soft clay soils
below the bottom of the borehole?
Shelby Tube
87.
What is the other term used for pore
water pressure?
Neutral stress
88.
What is the physical phenomenon of
water that causes water to be drawn up
many feet through pore spaces by
capillary action above the normal
groundwater table?
Surface tension
89.
What is the sieve number that is used to
separate fine sand from medium sand?
40
90.
What is the standard penetration test Nvalue when the number of hammer drops
needed to drive the split spoon sampler
for each of its 6-inch increments of 6, 9,
13, 15?
21
91.
What is the symbol for porosity?
n
92.
What is the symbol for void ratio?
e
93.
What is the symbol used to indicate the
hydraulic gradient?
i
83.
84.
85.
86.
94.
What is the term that is given to a clay soil
in which the existing vertical effective
stress on the clay today is less than the
maximum past pressure?
Over
consolidated
95.
What is the term used to indicate a deposit
of soft peaty soil that developed in a
depression formed when a huge ice chunk
broke off the retreating glacier and was
buried under outwash?
Kettle
96.
What range of theta values is usually found
in Montmorillonite clay?
5-6
97.
What should be the water content of clay
soil being compacted for a landfill liner or
as core of an earth-fill dam, both of which
need to have very slow permeability?
Wet of
Optimum
98.
What soil type causes the greatest problem
with capillary rise and subsequent frost
heave when a road's subgrade soils are
subjected to winter freezing ?
Silt
99.
What term is commonly used on the
earthwork construction site to describe that
a sheepsfoot roller has completed its work
of compacting the clay soil layer?
Walked out
100.
What thickness of clay layers would you
use to make calculations of primary
compression settlement
B/2
B/2
B
101.
What town in Norway suffered a major
quick clay landslide in 1978?
Rissa
102.
When drilling test borings in New England,
and the split spoon encounters refusal on
what appears to be bedrock, what must be
done to confirm that the top of bedrock has
actually been found?
Take a 10'
core sample
and if its all
rock, then its
bedrock
103.
When the loading on a soft clay is greater
than the clay previously experienced, what
happens between the clay particles that
then leads to the large settlement
observed in primary compression
Particle
bonds break
causing
them to be
packed
closer
together and
flatter
104.
When the nuclear density test apparatus is
used to determine density of compacted
soil in the field, what are the two types of
soils that it is most likely to experience
greatest difficulties due to interfere with
gamma ray and alpha ray transmissions?
Gravelly
glacial till
and
micaceous
silty sand
105.
Which common clay mineral has the most potential for shrink and swell when water content
changes?
Montmorillonite
106.
Which of the following 4 USCS classified soils would be best for use as an impervious cap over a
landfill, that must provide: impermeability, resistance to shrink-swell, and relative ease of
compaction
CL
107.
Which parameter of a clay soil has the greatest influence on the value of the Cv parameter of
the clay soil
Permeability
108.
Which type of soil deposit would be the best soil on which to build a large building that will have
shallow spread of footing foundations?
Drumlin
109.
Why is it not a good idea to use test pit excavations as the method of subsurface exploration
when you do not know where on the site the future tennis courts of shallow footings foundations
will be located?
Only accounts for soils
above 13' and the soils will
be disturbed
110.
Write Darcy's equation, that is used to calculate the quantity of groundwater flow?
Q = KiA
111.
Write the equation that is used to calculate the time required for vertical consolidation from a
clay stratum
t=(Tv*Hdr^2)/Cv
112.
Write the full equation for shear strength of clayey sand soil
Shear strength =
On*tan(theta)+ Capp
113.
Write the usual form of Bernoulli's Equation that is most often used in geotechnical engineering
practice when assessing groundwater flow through granular soil
ht = he + hp
CIVE 3300 Soil Mechanics Final Exam
Study online at quizlet.com/_5rtihl
1.
Q1.1: What is the sieve number
that is used to separate fine
sand from medium sand?
#40
10.
Q1.16: TRUE/FALSE - all clay soils exhibit
the same behavior and shear strength
when at their liquid limit, even if one
clay has LL = 130% and another clay has
LL = 25%.
TRUE
2.
Q1.2: What is the grain size
diameter (in mm) that is the
dividing line between fines
and sand particles?
0.075mm
11.
Q1.17-18: List the three most common
clay minerals that were discussed in
class, and circle the one that has the
most potential for shrink and swell when
water content changes.
Kaolinite
Illite
(Montmorillonite)
Q1.5: Mass of wet soil and can
before oven = 74.8g
Mass of dry soil and can after
drying = 61.3g
Mass of empty can = 31.2g
What is the water content of
the soil?
(74.8 - 61.3) / (61.3 - 31.2) =
44.85%
12.
Q1.21: What is the value of the plasticity
index for a clayey soil that has a liquid
limit of 48%, natural water content of
38%, and a plastic limit of 18%?
PI = LL - PL
PI = 48 - 18 = 30
4.
Q1.7-9: Use attached grain size
graph to determine
D10, D60, Cu
D10 = 0.095
D60 = 0.35
Cu = 3.68
13.
Q1.23: Which grain size curve on
attached graph for problem 23 shows
uniform sand?
Curve C
5.
Q1.10: TRUE/FALSE - the
diffuse double layer is the
basic structure of each clay
particle, and these clay
particle diffuse double layers
are the two different mineral
sheets bonded together.
FALSE
(DDL is the layer of water
surrounding the clay
particles, particles
surrounded by negative
charges so water like to
bond, montmorillonite DDL
> kaolinite b/c more surface
area)
14.
Q1.24: You have to choose between two
naturally occurring clay soils for
construction of a highway embankment.
Which clay is most readily usable for
building the compacted fill
embankment?
Clay B
Q1.11: The plastic limit test
involves rolling out a soil
thread until it just breaks into
small pieces when thread is
what diameter?
1/8 inch
15.
Q1.EC: What is the name of the lab test
that is used to determine the grain size
distribution of the particles of fine soil
that pass through sieve #200?
Hydrometer test
16.
TRUE
Q1.12-13: List four conditions
necessary for liquefaction to
occur in a natural sand deposit.
Fine sand
Loose soil
Saturated soil
Shaking
Q2.1: TRUE/FALSE - clay soils usually
have a void ratio that is greater than 1.0,
but not sand.
17.
CL
8.
Q1.14: TRUE/FALSE - a clay soil
is considered to be at its liquid
limit when the slot closes for
1/2 inch of its length at 35
drops of the brass cup.
FALSE
(it's 25 drops)
Q2.2: Which of the following USCS
classified soils would be best for use as
an impervious cap over a landfill, that
must provide: impermeability, resistance
to shrink-swell, and relative ease of
compaction?
CL, CH, ML, SC, SW
9.
Q1.15: What is the Cc value for
the soil whose grain size
curves gives the following
D10 = 0.6mm
D30 = 0.2mm
D60 = 0.05mm
Cc = (D30)^2 / (D10*D60) =
1.33
18.
Q2.5: If a sand soil has a void ratio value
of 0.3, then what term best describes its
density?
Very loose, loose, dense, very dense
Very Dense
19.
Q2.9-10: What symbol is used to denote
porosity and void ratio?
Porosity = n
Void ratio = e
20.
Q2.11: Equation for degree of saturation
using only volume and weight terms.
S = (Vw/Vv)*100
= (volume of
water / volume
of voids)*100
3.
6.
7.
Clay A: Wnat=30%, PL=15%, LL=28%
Clay B: Wnat=50%, Pl=48%, LL=76%
21.
Q2.12: Equation of water content using
only volume and weight terms.
%w =
(Ww/Ws)*100
= (weight of
water / weight
of solids)*100
22.
Q2.13: Equation of void ratio using only
volume and weight terms.
e = Vv/Vs
= (volume of
voids) /
(volume of
solids)
23.
Q2.14: Equation of specific gravity using
only volume and weight terms.
Gs =
Ws/(Vs*SWw)
= (weight of
solids) /
(volume of
solids *
specific weight
of water)
24.
25.
26.
27.
28.
29.
Q2.23-28: A soil has a total unit weight = 127
pcf, %w = 10%, and Gs = 2.69.
-Draw phase diagram
-Dry unit weight
-Void ratio
-Porosity
-Total unit weight if saturated
-SW or CL? Why?
-DUW =
115.45pcf
-e = 0.45
-n = 31%
-TUW if sat
= 135.1pcf
-SW b/c e
between
0.2-0.9 (avg
e values for
sand)
30.
Q2.EC: In the USCS system, write the three
words that describe a soil classified as ML
soil.
?
31.
Q3.1: TRUE/FALSE - in working with a
"performance" specification, only the
required percent compaction is specified, but
often the allowable range of moisture
content is also specified.
TRUE
32.
Q3.3: ASTM test specification says that all the
soil of a sample being tested in the lab
proctor test must pass through a #4 sieve if
the 4-inch diameter compaction mold is to be
used. If larger soil particles are present, what
mold size must be used?
6-inch
diameter
Q2.15: A soil with 4% fines and 51% passing
sieve #4, with a Cu=5.2, Cc=1.5 will be
classified as which soil?
SW, SP, GW, SM, GP
GW (i think)
Q2.16-17: Moist soil = 293g
Dry soil = 231g
Total volume = 124cm^3
Water content and dry unit weight?
%w = (293231)/231 =
26.8%
DUW =
(Ws/Vt) =
231/124 =
1.86g/cm^3
33.
FALSE
(8-10 inches
too much)
Q2.18-19: A soil has the gradation and
Atterberg limits shown below. What is its
classification by both USCS and AASHTO?
LL = 51%
PL = 26%
USCS =
AASHTO = A2-7, GI = 1.5
Q3.4: TRUE/FALSE - to achieve good degree
of compaction throughout the lift thickness of
a clayey soil, the thcikness of loose placed
fill before compaction should not exceed
about 8-10 inches.
34.
%w = (185127)/(12731)= 60.4%
Q2.20: Soil is tested and found to have
grain size distribution as shown on
attached sheet and has LL = 80%, PL =
28%. What is the USCS classification?
GC
Q3.5: What is the water content of a soil that
comes from a compaction sample?
Wet soil and container = 185g
Dry soil and container = 127g
Container = 31g
35.
Q3.7: The total unit weight of a soil sample is
132.5pcf. %w = 14%. What is the dry unit
weight of the soil?
Q2.21-22: Soil is tested and found to have
grain size distribution as shown on
attached sheet and has LL = 31%, PL = 24%.
What is the USCS and AASHTO
classificaiton?
SW-SM
A-2-4, GI =
-3.98 -> 0
DUW =
TUW/(1 +
%w)
=
(132.5)/(1.14)
= 116.23pcf
36.
Q3.8: TRUE/FALSE - the sheepsfoot roller is
the most often used to compact plastic clay
soils because the small peg-like feet apply
the high stresses needed to shear through
the clay and manipulate the clay soils into
denser condition.
TRUE
37.
Q3.9: What should be the water content of
clay soil being compacted for a landfill liner
or as core of an earth-fill dam, both of which
need to have very slow permeability?
Wet of
optimum
43.
Dry of optimum, at the optimum, or wet of
optimum
38.
39.
Q3.10: TRUE/FALSE - the optimum moisture
content of a clay soil is usually substantially
lower than that for a well graded granular
soil.
FALSE
Q3.13-14: What are the four details of the
modified proctor compaction test that is
done in a lab?
Hammer =
10lbs
Drop height
= 18"
Layers = 5
Drops = 25
Hammer weight, hammer drop height,
number of soil layers, number of drops each
layer
40.
41.
42.
Liquefaction
Q3.16: TRUE/FALSE - when clean, well
graded sand and gravel soil is being
compacted using a vibratory smooth-drum
roller, the density test should be conducted
at a depth of at least 5-inches below the
compacted surface to avoid the loosening
that occurs due to the intense vibrations the
roller applies.
TRUE
Q3.17: What is the effect of increased
compactive effort, on the same soil? That is,
using the modified proctor test instead of
the standard proctor test.
D
18) C
19) D
20) B
A) sheepsfoot heavy-drum roller (fat clay)
B) pneumatic rubber-tired roller (silt )
C) smooth steel drum vibratory roller
(sandy/gravel)
D) self-propelled pad foot-type of
sheepsfoot roller (silt/stiff clay)
(it's higher)
Q3.15: What is the greatest present day
concern for large embankment dams in
California built 100 years ago by the
hydraulic filling method?
Q3.18-20: Select the proper type of
compaction equipment that is most
appropriate for compacting the three
different soils below.
18)Well graded coarse to fine sand with very
little silt
19)Low plasticity sandy clay soil with 25% silt
20)Non-plastic silty sand without any gravel
44.
45.
Q3.21: TRUE/FALSE - the hammer used in
performing a standard proctor compaction
test weights 7.5lbs and is dropped 10 inches.
FALSE
Q3.22: In performing the modified proctor test
in the 4-inch diameter mold, the wet weight of
compacted soil and the mold was 11.4lbs. The
weight of the mold was 6.9lbs. The soil when
dried had water content of 12.1%. What is the
total unit weight of the compacted soil?
Wt = 11.4 6.9 =
4.5lbs
TUW =
Wt/Vt =
(4.5)/(1/30)
= 135pcf
(5.5lbs, 12
inches)
(Standard
proctor
test mold
volume =
1/30 ft^3)
46.
A) decreased max dry unit weight (DUW) and
increased optimum moisture content (OMC)
B) increased max DUW and increased OMC
C) decreased max DUW and decreased OMC
D) Increased max DUW and decreased OMC
Q3.24: When the nuclear density test
apparatus is used to determine density of
compacted soil in the field, what are the two
types of soils that it is most likely to
experience greatest difficulties due to
interference with gamma ray and alpha ray
transmissions?
B and D
a) very plastic clay
b) gravelly glacial till
c) m-f beach sand
d) micaceous silty sand
47.
Q3.25-26: Which of the three compaction
curves shown below would be typical of:
SW, CH?
SW = 1
CH = 3
48.
Q3.27-28: In performing the sand cone test
to verify field compaction, the wet unit
weight of compacted soil that you dug
from the hole = 5.1lbs. The soil was then
dried and water content = 16.5%. The
weight of the sand used in the and cone
device to fill only the hole you dug =
3.7lbs. Unit weight of sand used in the sand
cone = 95pcf.
What is the dry density of the compacted
soil?
Wt = 5.1lbs
%w = 16.5%
Wsand =
3.7lbs
TUW = Wt/Vt
=
(5.1)/(0.0389)
= 131.11
DUW =
TUW/(1+%w) =
(131.11)/(1.165) =
112.54pcf
Q3.EC1: What is the ASTM test number for
modified proctor compaction test?
D1557
50.
Q3.EC2: What term is commonly used on
the earthwork construction site to describe
that a sheepsfoot roller has completed its
work of compacting the clay soil layer?
?
Q4.1-2: A soil deposit is shown on the
attached setch for problem 1. You are to
determine the total and effective vertical
stresses for the soil element shown that is
30ft below ground surface.
sigma = 10(120
+ 115 + 118) =
3530psf
sigma' = 3530
- (20*62.4) =
2280psf
10ft sand (120pcf)
WATER TABLE AT LAYER BETWEEN
SAND/CLAY, 10FT BELOW GROUND
SURFACE
10ft clay (115pcf)
10ft to location, silt (118pcf)
52.
53.
delta-sigma =
(4000*15^2) /
(15 + 5 + 5)^2 =
1440psf
55.
Q4/13-14: A large area site that is 300ft by
450ft is raised by filling with 18ft thickness
of new soil fill that weighs 120pcf. You are
to determine the increase in vertical stress
at depth 20ft beneath original ground
surface. Groundwater is at original ground
surface.
delta-sigma =
(18)(120) =
2160psf
56.
Q4.15: TRUE/FALSE - Boussinesq
developed his basic equation in 1885 for
the purpose of determining the increase in
vertical stress in the ground due to a
building load or embankment or other
applied loading.
FALSE
57.
Q4.16-17: For the footing and soil
conditions shown on the attached sketch
for problem 16-17, calculate the increase in
vertical stress at the 9ft depth indicated
below the center of the 16ft square
footing using the attached M&N chart.
m = (B/2)/z =
(8/9) = 0.89
n = (L/2)/z =
(8/9) = 0.89
(From chart) Isigma = 0.158
delta-sigma =
(0.158)(320kips
/ 16^2)4 =
790psf
58.
Q4.3: For a 1.6 inch diameter cylindrical
speciman of soil that is loaded to failure
load = 52lbs, what is the compressive
strength?
P = F/A
= 52 /
(0.25pi1.6^2)
= 25.87psi
Q4.6: If the groundwater table is originally
at ground surface and then drops to be
15ft below ground surface, what is the
effect on the effective veritcal stress in
the ground?
Increased
Increased, decreased, or remains
unchanged
Q4.8-10: Use the approximate 2:1 method
to determine the increase in vertical stress
beneath the center of a 15ft by 15ft square
footing at a depth of 10ft below the
footing bottom. The footing bears on top
of ground and applies a pressure of
4000psf. Groundwater is at ground
surface.
(3.7lb)/(95pcf)
= 0.0389ft^3 =
Vt
49.
51.
54.
Q4.18-19: What is the increase in vertical
stress that occurs at 30ft depth below the
center of a 50ft diameter tank that applies
a contact pressure of 4000psf on the
ground?
Use
Boussinesq
Z/B = 30/50 =
0.6
(From chart) Isigma = 0.54
delta-sigma =
(0.54)(4000) =
2160psf
59.
Q4.20: TRUE/FALSE - when you use the
approximate 2:1 method to find the stress
increase below a new foundatio, the stress
increase that you calculate under the center of
the footing at depth B will be smaller than you
would calculate using the exact method such as
with Bouzzinesq chart.
TRUE
60.
Q4.21-22: What is the vertical stress increase
caused at a depth of 12ft beneath the corner of
a 8ft square footing that applies a contact
pressure of 3000psf on the ground surface?
Use M&N chart.
m = B/Z
= (8/12) =
0.67
n = L/Z =
(8/12) =
0.67
(From
chart) Isigma =
0.115
deltasigma =
(0.115)
(3000) =
345psf
61.
Q4.24-25: At a depth of 15ft below the mudline
in the soils below the bottom of Boston Harbor,
determine the listed stresses.
TUW = 125pcf
Mudline 35ft below water surface
Total and effective vertical stresses?
62.
63.
Q4.EC: A soil sample is tested in axial
compression and the stress vs. strain graph for
the test shown on the attached graph for
problem extra credit. What is the value for the
initial tangent modulus that is shown?
?
Q5.1: In the list below, circle the names that are
a type of igneous intrusive rock.
Granite
andesite, basalt, diabase, rhyolite, granite
64.
sigma =
(3562.4)
+ (15125)
=
4059psf
sigma' =
4059 (50*62.4)
= 939psf
(I think)
Q5.2: Limestone is calcium carbonate, and it is
easily weathered by acid rain. What is the name
of the other carbonate rock type that has
magnesium, which makes it more resistant to
weathering by acid rain?
65.
Q5.3: When drilling test borings in New
England, and the split spoon encounters
refusal on what appears to be bedrock,
what must be done to confirm that the top
of bedrock has actually been found?
Do two sets
of 5' cores
(10' total), if
all bedrock > bedrock
confirmed
66.
Q5.5: What is the term used to indicate a
deposit of soft peaty soil that developed in
a depression formed when a huge ice chunk
broke off the retreating glacier and was
buried under outwash?
Kettle
67.
Q5.8: What is the general name for windblown soil deposits (used for both sand and
silt )?
Aeolin
68.
Q5.9-10: List four of the eight major
different types of minerals from which
various types of rocks formed.
Feldspar
Gypsum
Quartz
Calcite
69.
Q5.11: TRUE/FALSE - in the formation of
igneous rock, rapid cooling of molten
magma results in a large and coarse grained
mineral structure and texture.
FALSE
70.
Q5.13-17: Classify each of the following
rocks as being either:
13) C
14) E
15) B
16) D (i think)
17) A
a) igneous-intrusive
b) sedimentary-clastic
c) metamorhpic
d) sedimentary-chemical
e) igneous-extrusive
13) schist
14) basalt
15) conglomerate
16) dolomite
17) granite
71.
(Gabbro
also
igneous
intrusive)
Q5.20: Which of the following types of soil
deposits would be the best soil on which to
build a large building that will have shallow
spread footing foundations?
a) outwash
b) drumlin
c) lacustrine
d) alluvium
e) kettle
Dolomite
72.
Q5.22-23: What are the following details for
the standard penetration test?
Hammer weight? Height of hammer drop?
B) drumlin
(lodgement
till also
good for
shallow
foundation)
140lb, 30
inches
73.
74.
Q5.24: What is the standard penetration test
N-value when the number of hammer drops
needed to drive the split spoon sampler for
each of its 6-inch increments are: 6, 9, 13, 15?
9+13 = 22
Q5.25-26: A 5-foot long core run recovers
pieces of rock core that have the following
lengths of each piece of rock core (in
inches): 5, 3, 4, 6, 1, 2, 3, 3, 1, 7, 4, 7, 6, 3.
Total of
piece
lengths = 55"
5 feet = 60
inches
Sum of
greater
than/equal
to 4" = 39
25) Recovery value?
26) RQD value?
25) 55/60 =
91.67%
26) 39/60 =
65%
75.
Q5.27: What is the name of the soil sampling
device that is used primarily to take
undisturbed samples of soft clay soils below
the bottom of the borehole?
Shelby tube
76.
Q5.EC1: What is the name of the
geotechnical instrumentation that is
installed in the ground to measure the
groundwater pressure in a clay soil?
Piezometer
77.
Q5.EC2: What is the name of the device that
is used in soft clay below the bottom of the
borehole to determine the shear strength of
the soft clay directly during the field
exploration?
Vane shear
test
78.
Q5.EC3: What is it not a good idea to use
test pit excavations as the method of
subsurface exploration when you do not
know where on the site the future tennis
courts or shallow footing foundations will be
located?
?
79.
Q5.EC4: What is the full name of the
quantity that is determined from results of
rock coring, that has the initials RQD?
Rock quality
designation
80.
Q5.EC5: What is the ASTM test designation
number and letter for performing the
standard penetration test?
D1586
81.
Q6.1: What is the term that is given to a clay
soil in which the existing vertical effective
stress (sigma'zi) on the clay today is less
than the maximum past pressure (sigma'c)?
Over
consolidated
82.
Q6.5: Write the equation used to calculate
OCR.
sigma'c /
sigma'zi
(or sigma'p
/ sigma'i)
83.
Q6.6: TRUE/FALSE - when determining the
value of the Cc parameter from the strain vs
log(pressure) graph that you get from a clay
soil consolidation test, the Cc value is
determined by calculating the ratio
FALSE
(logp2 - logp1) / (strain 1 - strain 2) for the
virgin compression part of the graph
84.
Q6.7: TRUE/FALSE - if a clay soil deposit
currently has an effective vertical stress
(sigma'z) that is less than sigma'c found in the
consolidation test, then the clay has an
OCR<1.
FALSE
85.
Q6.8: TRUE/FALSE - the one physical aspect
of clay soil that causes consolidation
compression of clay soils to usually be much
greater than compression of sand soil, even
under the same magnitude of loading, is the
fact that clay has a much larger initial void
ratio than does sand.
TRUE
86.
Q6.9: Explain in a brief statement what
happens initially to the effective vertical
stress in a saturated and normally
consolidated and clay soil stratum, when
loaded by a new 25-foot high embankment
that is quickly placed over a clay soil deposit.
Initially
effective
vertical
stress
stays the
same.
sigma' =
sigma - u,
and since
sigma and
u go up,
sigma' is
still the
same
initially.
87.
Q6.11-15: Know how to determine simga'i if
OCR is given.
OCR =
sigma'c /
sigma'i
88.
89.
90.
91.
92.
93.
94.
95.
Q6.16-17: Explain what happens in
the clay soil shown in the attached
sketch that would cause several
inches of settlement due to
compression of the soft normally
consolidated clay when there is a
lowering of the groundwater table
from Level A to Level B, as shown
in the attached sketch. Assume that
the clay is saturated and remains
submerged below groundwater
level.
In the clay soil as the
groundwater table
lowers, the simga'final
increases, and since
sigma'f increases,
there will be more
settlement.
Q6.18-19: What thickness of clay
layers would you use to make
calculation of primary compression
settlement, starting at the bottom
of a footing that is 12ft by 12ft in
plan dimension, and proceeding
down, assuming the clay layer is
40ft thick.
B/2 = 6'
B/2 = 6'
B = 12'
B = 12'
Q6.20: Equation to calculate the
settlement for the clay settlement
if sigma'f is less than sigma'c.
H(Cr/1+e0)(log(sigma'f
/ sigma'i))
Q6.EC1: IN a clay consolidation
test, what is the size (diameter and
height ) of the usual clay sample
that is tested in the onedimensional compression test?
d = 2.5"
h = 1"
Q6.EC2: Explain in terms of internal
particle structure of the clay, why
the slope of the graph of e vs
log(p) becomes steep when
effective stress on the clay soils
exceeds sigma'c.
The particle bond
begin to break, so
there will be more
settlement.
Q7.1: TRUE/FALSE - after a new
large wide area fill has been
placed over a soft clay soil layer
that has sand above and below, the
excess pore water pressure in the
clay caused by the fill placement
dissipates quickly at the top and
bottom of the clay stratum, but
very slowly in the middle of the
clay stratum.
TRUE
Q7.2: TRUE/FALSE - the rate at
which clay consolidates in virgin
compression is much slower than
when the clay compresses in
recompression.
TRUE
Q7.4: A 25-foot thick soft clay
stratum is single drained by sand
fill that has just been placed on
clay stratum top. How many days
will it take to achieve 80%
consolidation? Cv = 6x10^(-4)
cm^2/s
U% = 80% -> Tv =
0.567
Tv = (Cv*t)/Hdr^2
t = 6350.8days
96.
Q7.5: TRUE/FALSE - when a load is first
added to a saturated soft clay soil, such
as by placement of a big highway
embankment, the added pressure is
initially carried by an increase in the soil
effective stress.
FALSE
97.
Q7.6-7: There are two primary factors
that make plastic wick drains greatly
speed up the time for clay to
consolidate. What are they?
-Ch is 5-10x
larger than Cv
-Hdr is
decreased
98.
Q7.11: Write the equation that is used to
calculate the time required for vertical
consolidation from a clay stratum.
t=
(Tv*Hdr^2)/(Cv)
99.
Q7.12-13: Explain in a brief, concise
statement, why the Ch value of a clay
soil is usually 2-5 greater than the value
of the clay soil's Cv parameter.
Clay particles
tend to be
horizontally
layered, so it is
easier for water
to pass through
horizontally.
100.
Q7.14: Which one of the following
parameters of a clay soil has the
greatest influence on the value of the
Cv parameter of the clay soil?
C) permeability
a) void ratio
b) porosity
c) permeability
d) water content
101.
Q7.15: TRUE/FALSE - when determining
the value of Cv from the results of a
consolidation test, the appropriate load
increment to use the dial vs log time
data from is in the over-consolidated
stress range where sigma'i < sigma'c.
FALSE
102.
Q7.16: When the loading on a soft clay is
greater than the clay previously
experienced, what happens between the
clay particles that then leads to the
large settlement observed in primary
compression. Explain.
The particle
bonds break,
allowing for
more settlement
to happen.
103.
Q7.19-20: An oil tank is constructed over
a 15ft thick clay layer that overlies an
impervious shale bedrock. Predicted
total settlement is 8inches. After four
months, 3 inches of settlement has
occurred.
19) Cv = 0.0188
in^2/min
20) 1014.9 days
19) Calculate Cv value in (in^2/min)
20) How many data to achieve 7.2 inches
of settlement
104.
Q8.1: What is the fundamental property of
sand soil that is the basis for its shear
strength?
Friction
105.
Q8.3: TRUE/FALSE - When using the Mohr's
circle to determine the shear strength of a
sand soil tested in triaxial compression, the
value of the major principle stress is the
confining pressure, and the minor principle is
the axial stress.
FALSE
Q8.6-8: What is the effect on sand shear
strength that is caused by each of the
following changes in the granular soil
characteristics listed below?
Increased
density ->
Increased
Decreased
particle
angularity
->
Decreased
Sand is
more well
graded ->
Increased
106.
Increased density ->
Decreased particle angularity ->
Sand is more well graded ->
107.
Q8.10: Know where major principle stress is
located on Mohr's circle.
other way
around
Where
circle
passes xaxis, but
the bigger
number
(700psf
on quiz)
108.
Q8.11: TRUE/FALSE - when the triaxial test is
used to determine the shear strength of a
sand soil, the value of the shear strength
parameter that is determined in the triaxial
test will be less than determined using direct
shear test on the same sand.
TRUE
109.
Q8.13-14: Do the question...
Major
principle
stress =
3100psf
Minor
principle
stress =
450psf
110.
Q8.15-16: For direct shear test, explain why the
dense sand curve eventually reaches the lose
sand curve. Base your explanation on the
sand particle movement and the changes in
void ratio that occur during shear strain.
?
111.
Q8.19: TRUE/FALSE - when the pore water
pressure in a sand soil is increased, it will
cause the available shear strength of the
sand to also be increased by a similar
amount.
FALSE
112.
Q8.EC1: What is the meaning of the angle of
repose?
The max
angle a
sand fill will
make
without
horizontal
movement
113.
Q8.EC2: In a sand soil, what is the four word
name for the parameter that is used to
define the sand's shear strength, which also
is the inclination of the shear strength
envelope?
Angle of
internal
friction
114.
Q9.1: Write the full equation for shear
strength of clayey sand soil.
tow = sigma'
* tan(phi) +
C
115.
Q9.4-6: The question...
Undrained
shear
strength (Su)
= 600psf
Unconfined
compressive
strength (qu)
= 1200psf
116.
Q9.7: TRUE/FALSE - when the loading on a
clay soil is rapidly increased, such as will
happen when a new embankment is built
over a soft clay deposit, the pore water
pressure in the clay will initially increase a
lot, however this increased pore pressure
causes an immediate decrease in the clay's
undrained shear strength.
FALSE
117.
Q9.10: TRUE/FALSE - the fundamental
property of clay soil is the basis for its
undrained shear strength is actually
apparent friction.
FALSE
118.
Q9.11: In the equation for shear strength of
clayey sand soil, what part applies for the
clay component of the clayey sand soil?
The + C
(that's the
cohesion)
Q9.12: TRUE/FALSE - in a CU triaxial
test, the Su of an over-consolidated
clay will only increase when the
effective confining pressure is raised
to a pressure greater than the
maximum effective vertical stress that
existed in the ground when the
sample was retrieved by using the
shelby tube sampler during subsurface
exploration.
TRUE
120.
Q9.14: If the unconfined compressive
strength (qu) of a clay sample is
1800psy, what will be the cohesion of
the clay when it is tested in
unconfined compression?
Su = qu/2
Su = 900psf
121.
Q9.15: TRUE/FALSE - the diameter of
the Mohr's circle graph from a triaxial
test represents the deviator stress,
and equals to the maximum shear
strength of clay.
FALSE
Q9.16: Briefly explain the fundamental
reason that causes there to eventually
be an increase of shear strength of a
normally consolidated clay soil which
is below a newly constructed
embankment, the increase happening
slowly with time after the
embankment is constructed.
The increase
happens because
over time the clay
drains, and in NC
clay, drained shear
strength>undrained
shear strength.
Q9.17: TRUE/FALSE - initial undrained
shear strength of stiff clay soil below
the bottom of a deep excavation is
much greater than the drained shear
strength that will develop after many
months of unloaded condition caused
by excavation.
TRUE
Q9.18: TRUE/FALSE - if in a CU triaxial
test on stiff clay, confining
pressure=10psi, axial stress=30psi, and
pore water pressure=5psi at failure,
then the deviator stress at failure was
25psi.
FALSE
125.
Q9.EC1: What range of phi values is
usually found in montmorillonite clay?
?
126.
Q9.EC2: What town in Norway
suffered a major quick clay landslide
in 1978?
Rissa
Q10.3: Write Darcy's equation that is
used to calculate quantity of
groundwater flow.
Q = kiA
119.
122.
123.
124.
127.
128.
Q10.4-7: Match
a) phreatic surface
b) aquifer
c) aquiclude
d) artesian
e) vadose
f) vulcanized
4) D
5) E
6) A
7) C
4) groundwater stratum overlain by a
clay layer and under pressure
5) name of the zone of soil above
the groundwater table
6) another name for the groundwater
table
7) name of soil stratum through which
groundwater will not flow freely
129.
Q10.8-9: Explain why the
permeability of clay soil is so slow
and seemingly not affected by the
total volume of voids in the soil,
even though clay has 2-5 times the
voids of sand.
Because clay
particles are
surrounded by
negative charges
that absorb lot of
water and slow
down flow.
130.
Q10.11: What soil type causes the
greatest problem with capillary rise
and subsequent frost heave when a
road's subgrade soils are subjected
to winter freezing conditions?
Silt
131.
Q10.16: TRUE/FALSE - the in-field
pumping test is the best way to
determine the overall permeability
of the overall soil deposit.
TRUE
132.
Q10.17-18: What are the names of the
two different types of equipment
that may be installed in completed
borehole to determine groundwater
level or pressure in a soil deposit.
Observation well,
piezometer
133.
Q10.19: Which instrument measures
water level directly? (observation
well or piezometer)
Observation well
134.
Q10.21-22: What is the symbol for
hydraulic gradient, what is the
equation for it?
i = (delta h) / L
135.
Q10.23: Write the usual form of
Bernoulli's equation that is most
often used in geotechnical
engineering practice when assessing
groundwater flow through granular
soil.
hT = hp + hz
total head =
pressure head +
elevation head
136.
Q10.24: What is the physical phenomenon of water that causes water to be drawn up many feet through pore
spaces by capillary action above the normal groundwater table?
Surface
tension
Soil Mechanics
Study online at quizlet.com/_67iq93
1.
Atterberg limits
are
7.
Plastic limit (PL)
The water contents at the boundaries
between the states of consistency
2.
3.
4.
The consistency of
a soil is the degree
of __________
between the
particles that can
resist ______________
or ___________
adhesion
deformation or
rupture
During placement
of engineered fill,
_______ testing is
performed to
evaluate the
_______________ effort
and determine
whether the soil
compaction is
adequate to meet
job specifications
density testing
compactive effort
boundary between the semisolid and
plastic states
8.
The shear strength
of a
_______________________
soil is affected by
the
___________________
pressure that
develop when the
soil is submerged.
9.
Shrinkage limit
(SL)
cohesionless soil
porewater pressure
Liquid limit (LL)
boundary between the solid and
semisolid states of soil
10.
Soil passes from a
solid state, when
dry, through the
semisolid, plastic,
and liquid states
as water is
added
11.
Three types of
direct shear test
are performed on
saturated, or
nearly saturated
clays
1. Unconsolidated - undrained (UU)
2. Consolidated - undrained (CU)
3. Consolidated - drained (CD)
boundary between the plastic and liquid
states
5.
Most common
methods by which
soil density is
determined are
nuclear and sand-cone density tests
6.
Partially saturated
samples will
develop an
apparent ___________
due to surface
tension formed
between _________
___________.
apparent cohesion
soil particles
Soil Mechanics Exam 3
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1.
as consolidation progresses,
pore pressure ___
moves toward the
hydrostatic pressure
2.
benefits of compaction
increase strength, reduce
permeability, control
shrink/swell
3.
cohesion
resistance to movement
even when the normal force
is zero
4.
compaction is evaluated base
on
dry unit weight
5.
CU test specifications
pore pressure
measurements: effective
stress
no pore pressure: total
stress (CD also)
6.
7.
direct shear test
characteristics
fast, simple, inexpensive
no drainage control, forces
failure plane
usually saturated soils
drained soils
= no excess pore pressure
all soils long term (static
conditions)
sand and gravels short
term
8.
effective stress
stresses on the soil
framework
9.
field verification for
compaction
sand cone, nuclear density
gauge, drive cylinder
10.
fluid flow is considered to be
laminer in more cases
11.
how to calculate: AF, delta
sigma, sigma 1, sigma 1', sigma
3', C, R
Af= Ao/1-e
delta sigma= force/Af
sigma 1= sigma 3 + delta
sigma
sigma 1'= sigma 1- u (pore
pressure)
sigma 3'= sigma 3- u
C= sigma 1'+sigma 3'/2
R= sigma 1-sigma 3/2
12.
how to calculate FS
FS = resistance/demand
FS = s/t
if FS <1 failure
13.
how to find dry unit weight for
curve
gamma dry = gamma/ 1+wc
where gamma =
weight/volume
14.
how to solve cut/fill problems
use phase diagram
15.
parallel flow: the layer with
the highest K...
dominates flow rate
16.
perpendicular flow: the layer
with the highest K...
does not dominate, lowest
K dominates
17.
relative density method
is better for sands and
gravels than
the proctor method
18.
results for CD test
effective stress c', phi'
19.
results for CU test
either total or effective c, phi, or
c', phi'
20.
results for direct shear
effective stress, c', phi', where c'
is normally zero or near zero
21.
results for unconfined
compression
total stress, qu and Su
22.
results for UU test
total stress, Su if saturated
(phi=0)
if unsaturated, c, phi
23.
soil factors that effect K
pore size, fabric, particle shape
and roughness
24.
special UU test
Unconfined compression (UC),
fast, easy inexpensive
does not simulate field
conditions
total stress test
25.
specification for
compactors
no trees, no white goods, no
rocks or broken concrete,
maximum layer thickness
26.
strength equation
strength= sigma'*tan(phi)+c'
strength = c = Su for phi = 0
Su = qu/2 for UC test where qu =
sigma 1
27.
three tests under triaxial
consolidated drained (CD)
consolidated undrained (CU)
unconsolidated undrained (UU)
28.
triaxial test
characteristics
the gold standard of testing,
flexible, simulates a wide range
of conditions
expensive, more complex, time
consuming
29.
undrained soils
= no drainage
clays and silts short terms
potentially all soils under
dynamic loading (earthquake)
30.
zero air voids curve
upper limit of water content for
a given dry unit weight
Lecture #4 : Radiology - A Historic Perspective Outline
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1.
1643
Year when Evangelista Torricelli invented the
barometer
20.
Benjamin
Franklin
Conducted many electrical experiments
2.
1646
Year when Otto van Guericke invented the
air pump
21.
Calcium
Tungstate
A great improvement over barium
platinocyanide
3.
1659
When Robert Boyle repeated the experiment
of Guericke
22.
Charles
Dufay
Works with glass,silk, and paper, distinguished
two different kinds of electricity
4.
1727
When did Johann Heinrich Schulze
produced the first photographic copy of
written materials
23.
Clarence
Madison
Dally
5.
1831
When did Michael Faraday induced an
electric current by moving a magnet in and
out of a coil
Thomas Alva Edison assistant, who suffered
severe radiation damage as result of his
research in fluoroscopy that extensively use
radiation
24.
December
28, 1895
When was Roentgen submitted his first book
and realized that it could potentially have
medical use
25.
Democritus
Described materials as being composed of
ultimante particles
26.
Digital
imaging
Applied in most of the imaging performed in
radiology today. This includes diagnostic
ultrasonography, nuclear medicine, magnetic
resonance, and digital fluorescopy and
radiography
27.
Early
scientists
and
craftsmen
Archimedes, Democritus, And Thales
28.
Electricity,
Vacuums,
and Imagerecording
materials
3 specific aspect of physical science that help
pave the way for the discovery of X-rays
29.
Enrico Fermi
He induced a successful chain reaction in a
uranium pile at the University of Chicago
30.
Ernest
Lawrence
Invented the cyclotrons chamber that made it
possible to accelerate particles to high
speeds for use as projectiles
31.
Evangelista
Torricelli
Produced the first-recognized vacuum when
he invented a barometer
32.
Films
Capable of resolving structures smaller than
the human eye can see
33.
Films
processor
Produce radiographs in 90 secs; 60 and 45
sec machines are also available
34.
Fluorescopy
A procedure using x-rays to image inner parts
of the body in movement and motion
35.
George
Eastman
He produced and patented roll-paper film
36.
Heinrich
Daniel Ruhm
Korff
He made the most significant improvement of
induction coils
6.
7.
1865
1871
When Herman Sprengel repeated the
experiment of Guericke
When did Richard Leach Maddox produced
a films with a gelatin silver bromide
emulsion that has remained the basic
component for film
8.
1884
When did George Eastman produced and
patented roll-paper film
9.
1888
Roentgen determined the x-rays had a
degree of penetrative power dependent on
the density of the material
10.
1888
When was Roentgen became interested in
cathode ray experiment with the Crookes
tube, which he worked with until his
discovery of x-rays
11.
1901 in
Stockholm
In what year and place did Wilhelm Conrad
Roentgen received the first Nobel prize in
Physics
12.
1932
When did Ernest Lawrence invented the
cyclotrons chamber
13.
1934
Discovered of the First artificial radioactivity
14.
1942
When did Ernest Fermi induced a successful
chain reaction in a uranium pile at the
University of Chicago
15.
AbbejeanAntoine
Nollet
Made a significant improvement in the
electroscope, a vessel for discharging
electricity under vacuum conditions
16.
Anna Bertha
Ludwig
She was working in Zum Grunen Glas as a
waitress
17.
Anton Henri
Becquerel
Father of Radioactivity
18.
Archimedes
Explained the reaction of solids when they
are placed in liquids
19.
Barium
platinocyanide
What was the effect that Roentgen produce
of some type of x-ray by continuously
producing the fluorescent effect
37.
History of
radiology
A story of how creative individuals built on the
discoveries and inventions of others, adding
their own inventive techniques to create the
radiologic practices we have today
38.
Image
recording
materials
Important to the investigators of the cathode
rays
39.
In 1888
Roentgen was offered employment at the
University of Wurzburg. He accepted the offer,
knowing of the university's new physics
institute and its impressive facilities
40.
In 1945
The result of this breakthrough were first
demonstrated when atomic devices were
denoted experimentally
54.
Michael
Idvorsky
Pupin
He was the one who made the first known
Radiograph in US.
55.
Modern
Radiology
Development of fiber optics, that is, manmade fibers with the unique characteristics of
allowing light to turn a curve, has had a
significant impact on radiology and on all
disciplines of medicine
56.
Modern
Radiology
Many specialist have emerged, including
computed tomography, magnetic resonance
imaging, nuclear medicine, radiation therapy,
ultrasound, neuro vascular radiology digital
imaging, ang routine diagnostic radiology
57.
November 8,
1895
When were x-rays discovered
58.
Nuclear
Radiology
Branch of radiology using radioactive
materials for medical diagnosis and treatment
59.
On a New
Kind of Rays
First book that Wilhelm Conrad Roentgen
submitted to Wurzburg Physico-Medical
Society
60.
Otto van
Guericke
Invented an air pump that was capable of
removing air from a vessel or tube
61.
Philipp
Lenard
He furthered the investigation of cathode rays.
He found that cathode rays could penetrate
thin metal and would project a few
centimeters into the air
62.
Pierre Curie
He noticed that the radium killed diseased
cells, which was the first suggestion of the
medical utility of radioactivity
63.
Pierre, Marie
Curie, and
Anton Henri
Becquerel
The 3 persons credited with Radioactivity who
were awarded Nobel prize for Physics in 1903
64.
Radioactivity
Property of certain elements to emit rays or
subatomic particles spontaneously from
matter
65.
Radioactivity
Spontaneous disintegration of unstable atomic
nuclei to atomic nuclei to form more
energetically stable atomic nuclei
66.
Richard
Leach
Maddox
He produced a films with a gelatin silver
bromide emulsion that has remained the basic
component for film
In early
days in
discovery
Some seriously attempted to explain the
nature of the rays, others were vague, some
were comic, and still others were clearly
dishonest
In early
days in
discovery
Serious efforts were made to protect those
who worled with the rays and those who
would be exposed to yhem. These effosrts
have been successful
43.
In early
days in
discovery
Thomas
Alva Edison
Noticed and questioned the effects of x-rays.
He complained that his eyes were sore and
red after working with fluorescent tube
44.
Isaac
Newton
Built and improved the static generator
45.
January 2,
1896
Pupin made the first Radiograph in US
46.
Johann
Heinrich
Schulze
He produced the first photographic copy of
written materials
47.
Johann
Wilhelm
Hittorf
Conducted several experiments with cathode
rays, which are streams of electrons emitted
from the surface of a cathode
48.
Marie Currie
Refined the knowledge of radioactivity and
purified the radium metal
49.
Marie Currie
She received a noble prize in 1911
50.
Marie Currie
She made radiographic equipment for the
French military medical service
51.
Marie Currie
She developed 20 mobile radiographic units
and 200 installations for the army
67.
Robert
Boyle
His experiments with electricity earned him a
place among the serious investigators
52.
Memphis or
Tennessee
Location of First Army school of
Roentgenology
68.
Thales
Discovered some of the effects of electricity
69.
Michael
Faraday
He induced an electric current by moving a
magnet in and out of a coil
Thomas Alva
Edison
In early days in the discovery he attempted to
explain the nature of the rays to the citizens in
the United States through Newspapers
41.
42.
53.
70.
Thomas Alva
Edison
Discovered the Calcium Tungstate
71.
Thomas Alva
Edison
He worked with fluorescopy
72.
Wilhelm Conrad
Roentgen
Died due colorectal colon on February 10, 1923 in Munich
73.
Wilhelm Conrad
Roentgen
He was the only child of Friedrich Conrad Roentgen and on 1872 he was married to Anna Bertha Ludwig
74.
Wilhelm Conrad
Roentgen
He was born on March 27, 1845 in Lennep, Germany
75.
Wilhelm Conrad
Roentgen
Who discover X-rays
76.
William Crookes
He further develop the study of cathode rays and demonstrated that matter was emitted from the cathode with
enough energy to rotate a wheel placed within a tube
77.
William Gilbert
One of the first to extensively study electricity and magnetism
78.
William
Godspeed
He produced a radiograph in 1890.
79.
William
Godspeed
His achievement was recognized only in retrospect and after the discovery of x-rays by Wilhelm Conrad
Roentgen
80.
William Morgan
While conducting experiments with electrical discharges, He notice the difference in color of partially evacuated
tubes
81.
William Watson
Demonstrated a current of electricity by transmitting electricity from a Leyden jar through wires and a vacuum
tube
ORIGIN OF SOIL AND GRAIN SIZE
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1.
Adsorbed water
The innermost layer of double-layer water,
which is held very strongly by clay
19.
Orthoquartzite
A very pure quartz sandstone composed of
usually well rounded quartz grains
cemented by silica. Often 99% SiO2
2.
Bowen's
Reaction Series
the simplified pattern that illustrates the
order in which minerals crystallize from
cooling magma according to their
chemical composition and melting point
20.
Phyllite
is a metamorphic rock, which is derived
from slate with further methamorphism
being subjected to heat greater than 250300 °C
3.
Breccia
particles of rock are more angular
4.
clay minerals
the chemical weathering of feldspar
produces. gives the plastic property to
soils
21.
Plutons
intrusive igneous rocks
22.
Quartzite
a metamorphic rock composed of quartzrich sandstone
23.
Schist
is a type of metamorphic rock derived from
several igneous, sedimentary rocks, and
low-grade metamorphic rocks with a wellfoliated texture and visible flakes of platy
and micaceous minerals
24.
sedimentary
rock
The type of rock that is made of hardened
sediment.
25.
silts
are the microscopic soil fractions that
consist of very fine quartz grains and some
flake-shaped particles
26.
slate
A type of Metamorphic rock that was once
shale rock formed by heat and pressure.
low-grade metamorphism
27.
soil
product of rock weathering
28.
Weathering
The breaking down of rocks and other
materials on the Earth's surface.
5.
clay minerals
are complex aluminum silicates composed
of two basic units : SILICA TETRAHEDRON
AND ALUMINA OCTAHEDRON
6.
Clays
are mostly flake-shaped microscopic and
submicroscopic particles of mica
7.
Detrital
Sedimentary
Rocks
form from sediments that have been
weathered and transported. they have
clastic texture
Dipole
a molecule that has two poles, or regions,
with opposite charges positive and
negative
8.
9.
double-layer
water
all the water held to clay particles by
force of attraction
10.
Evaporites
sedimentary rocks formed from minerals
left after water evaporates
11.
Gneiss
is a metamorphic rock with a banded or
foliated structure, typically coarse grained
and consisting mainly of feldspar, quartz,
and mica. derived from high-grade
metamorphism
12.
hydrogen
bonding
a third mechanism by which water is
attracted to clay particles
13.
igneous rock
a type of rock that forms from the cooling
of molten rock at or below the surface or
molten magma
14.
igneous,
sedimentary,
metamorphic
3 types of rocks
15.
kaolinite, illite,
montmorillonite
important clay minerals
16.
marble
is formed from calcite and dolomite
recrystallization
17.
Metamorphism
the process in which one type of rock
changes into metamorphic rock because
of chemical processes or changes in
temperature and pressure
18.
Mudstone/Shale
has a blocky aspect. grain size less than
1/16 mm
Grain Size Analysis
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1.
75-4.75mm
gravel
2.
75um to 2um
silt
3.
300-75mm
cobble
4.
ASTM
number for
sieve 5mm
No.4
5.
ASTM
number for
sieve
.080mm
No.200
6.
Attenberg
Limits
limits describing the moisture content within a
soil sample and it's given behavior.
7.
Clay
Summary
Low values of strength, modulus and
permeability. Material is non granular,
cohesive and water has an important effect on
material structure.
Coarse
Grained soils
(sand gravel)
more than 50% of the soil sample is larger
than 0.075mm
Coefficient
of Curvature
(Cc)
A measure of the curvature of the grain size
distribution plot. Well-graded sands and
gravels have coefficients of curvature
between 1 and 3
Coefficient
of
Uniformity
(Cu)
A measure of the grain size uniformity using
the ratio of particle sizes D60 to D10.
11.
Cohesionless
soil
sand and gravel, anything above 0.002mm
(clay)
12.
cohesive
soils
loam, clay, silt; particles in soil bond to one
another
13.
effect of
particle size
on soil
strength
larger the agg = stronger, permeable
compared to smaller sizes
14.
Fine Grained
Soils (clay
silt )
more than 50% of soil is smaller than
0.075mm
15.
Grain size
analysis
a test used to determine grain size distribution
of a given soil sample, according to ASTM
16.
Gravel and
Sands
Summary
17.
How does
USCS define
a soil?
8.
9.
10.
18.
Hydrometer
Analysis
Mechanical analysis for particle sizes smaller
than 0.075 mm in diameter, based on the
principle of silt and clay settlement in water
and is a measurement of the density
"suspension"
19.
Hydrometer
Analysis
Mechanical analysis for particle sizes smaller
than 0.075 mm in diameter
20.
Hydrometer
analysis is
used for:
used for analyzing grains less than 0.075mm
21.
Liquid Limit
the water content, above which soil loses
plasticity and becomes a liquid
22.
Liquid Limit
(LL)
The moisture content above which the soil
behaves as a liquid.
23.
Plasticity
Index (PI)
range in water content between PL and LL
(plastic); PI = LL - PL
24.
Plastic Limit
The moisture content at which a soil starts to
change from a semisolid to a plastic state.
25.
Plastic Limit
(PL)
moisture content at which the soil becomes
moldable without showing any cracks. 3mm
cone can be rolled.
26.
sait sieve
sizes
5mm, 2mm, 1mm, 630um, 315um, 160um, 80um
and pan
27.
sand
4.75mm-75um
28.
shrinkage
limit
Water content at which the soil volume is
lowest and the soil is completely saturated.
29.
Siege
analysis is
used for:
used for analyzing grains greater than
0.075mm
30.
Silt
Summary
Medium values of strength and permeability.
Material is granular, cohesionless and water is
important in material structure.
31.
soil
consistency
The strength with which soil materials are held
together or the resistance of soils to
deformation and rupture. Term used to
describe the degree of firmness, indicated via
moisture content.
32.
soil fabric
the physical constitution of a soil material as
expressed by the spatial arrangement of the
solid particles and associated vibes.
High strength, modulus and permeability.
Granular and cohesionless.
33.
soil fabric
the physical constitution of a soil material as
expressed by the spatial arrangement of the
individual particles and associated voids
The nature of the soil (organic vs. inorganic),
soil groups (majority particle size) and
plasticity (a chart from atterberg limits)
34.
soil
structure
The arrangement of primary soil particles into
compound particles or aggregates that are
separated from adjoining aggregates.
35.
soil structure
How the particles that make up a soil are organized and clumped together, expressed by the
size, shape and arrange of groups of solid particles and associated voids.
36.
soil texture
Relative amounts of the different types and sizes of mineral particles in a sample of soil.
37.
Solid Limit
The moisture content at which soil starts to slightly loosen from a solid to a semi-solid state.
38.
Standard Sieve Sizes
5mm, 2mm, 1mm, .630mm, .315mm, .160mm, .080mm
39.
Two types of descriptions of soil
soil type (behaviour based), soil particle size distribution (size based)
40.
Well graded soil
broad, well distributed range of sizes results in less soil pores, compact more effectively, and
drain water less efficiently
41.
what can be inferred from a
poorly graded distribution curve?
poor distribution of particle sizes, favoring one size and not including others.
42.
what can be inferred from a well
graded distribution curve?
uniform distribution and includes all sizes of particles.
43.
what does Dn stand for in a grain
size distribution curve?
the diameter that n% of the sample will be finer than.
44.
What is used to classify soils (our
purposes)?
USCS (Unified Soil Classification System)
Chapter 2: Origin, Grain Size and Shape
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1.
At a construction site, the
subsurface investigation indicates
the presence of a residual soil
deposit. The grain size of the soil
at this site will generally
___________.
increase with depth.
2.
Calculation of the coefficient of
gradation (Cc) of soil requires
Cc = (D30^2) / (D60 *
D10)
3.
Characteristics of the soil
deposits formed from braided
streams
The grain sizes usually
range from gravel to silt.
AND
Clay-sized particles are
generally not found.
AND
The soil in a given
pocket lens is generally
uniform.
AND
At any given depth, the
void ratio and unit
weight may vary over a
wide range within a
lateral distance of only
a few meters.
4.
The clay minerals are a product
of chemical weathering of
__________.
feldspars.
AND
ferromagnesians.
AND
micas.
12.
Organic Soils
Organic soils are usually found
in low-lying areas where the
water table is near or above
the ground surface.
AND
Organic soils are highly
compressible.
AND
The moisture content of organic
soils may range from 200 to
300%.
13.
Particle size distribution
curve is used for
_______________.
determining the percentages of
different particle-size fractions
in a soil.
AND
comparing different soils.
AND
classifying soils.
14.
The particles smaller than
0.075 mm are referred to
as __________.
fines.
15.
Physical properties of soil
depend on
size of soil grains.
AND
shape of soil grains.
AND
chemical composition of soil
grains.
16.
Select the incorrect
statement.
Organic soil deposits are
usually encountered in desert
areas.
17.
Small sand particles
located close to their
origin are generally
angular.
18.
The soil deposit laid down
by glaciers consists of
sand, silt, clay, gravel and
boulders, and
is usually called ________.
drift
19.
A soil in which the particle
sizes are distributed over
a wide range is termed
____________.
well graded soil.
5.
Effective size of soil particles
denoted by __________________.
D subscript 10
6.
For a granular soil, effective size
(D10) = 0.09 mm, and coefficient
of uniformity (Cu) = 4.56. What
will be the diameter
corresponding to 60% finer?
Solve for D subscript 60
Cu = D subscript 60 / D
subscript 10
7.
For clayey and silty soils, the
specific gravity of particles may
vary from ____________
2.6 to 2.9
8.
Granite, gabbro and basalt are
some common types
of______________.
igneous rock
9.
Hydrometer analysis for particlesize distribution curve is based on
__________________.
Stokes' Law
20.
The soils transported and
deposited by wind are
called __________.
aeolian soils.
10.
Limestone is a ______.
sedimentary rock
21.
800 m^2/g
11.
Metamorphic Rocks
Marble
Gneiss
Quartzite
The surface area of the
montmorillonite particles
per unit mass is about?
22.
When water is added to the clay, the innermost layer of double-layer water,
which is held very strongly by clay, is called ___________?
adsorbed water.
(This water, which can not be easily removed, is
more viscous than is free water.)
23.
Which of following statements does not describe the characteristics of the soil
deposits
formed from braided streams?
The soil in a given pocket lens is generally nonuniform.
24.
Which of the following carries a net negative charge on its surfaces?
clay
25.
Which of the following is not a clay mineral?
Biotite
26.
Which of the following is not a metamorphic rock?
Dolomite
27.
Which of the following minerals is the most resistant to weathering?
Quartz
Ch. 2 (Soil Deposits - Origin, Grain Size & Shape)
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1.
Aluminum
Octahedron
6 hydroxide surrounding one aluminum
16.
octahedral
sheet
combination of the octahedral aluminum
hydroxyl units
2.
bulky
-formed by mechanical weathering of
rock and minerals
-ex: angular, subangular, subrounded,
rounded
17.
sand
made up of mostly quartz and feldspar (&
other mineral grains)
18.
shape, size,
weight
settling v depends on _____,_______,______
19.
sieve
analysis
Analysis for grain sizes larger than 0.075 mm
in diameter
20.
silica sheet
The combination of tetrahedral silica units
21.
silica
tetrahedron
a grouping of one silica ion and four oxygen
ions that forms the basic building block of a
silicate
22.
silt
microscopic soil fractions that consist of very
fine quartz grains and some flake-shaped
grains that are fragments of micaceous
minerals
23.
specific
gravity (Gs)
ratio of density of the material to the density of
water
24.
Stokes Law
-The speed at which particles of sediment
drops based on radius and density
-bigger particles drop faster
25.
Uniformity
Coefficient
= D60/D10
26.
Well
graded soil
has a Cu greater than 4 for gravels and 6 for
sands, and a Cc between 1 and 3
3.
clay
-mostly flake-shaped microscopic and
submicroscopic grains of mica, minerals,
and other minerals
-grains which develop plasticity when
mixed with a limited amount of water
4.
clay minerals
-silica tetrahedron
-aluminum octahedron
5.
Coefficient of
Curvature
(/Gradation) (Cc)
= (D30)^2/(D60*D10)
6.
Diffuse double
layer
-Clay has a net neg. charge
-In dry clay, the neg. charge is balanced
by exchangeable cations surrounding the
grains
-When water is added, the cations and a
small # of anions float around the clay
grains
(pulls + to clay surface)
7.
effective grain
size
grain size corresponding to the one that is
10% finer by weight line on the grain size
distribution curve
8.
flaky
-have very low sphericity (.01 or less)
-predominately clay materials
9.
gravel
pieces of rocks with occasional grains of
feldspar and other minerals
10.
Hydrometer
analysis
Analysis for grain sizes smaller than 0.075
mm in diamater
11.
Illite
-consists of 1 gibbsite sheet bonded to 2
silica sheets (one at the top and another
at the bottom)
-Potassium between molec
12.
Kaolinite
consists of repeating layers of elemental
silica-gibbsite sheets
13.
kaolinite, illite,
montmorillonite
3 main clay components
14.
k,i,m
Clay component (least to greatest
moisture absorbance)
-put first letter of name
15.
Montmorillonite
-consists of 1 gibbsite sheet bonded to 2
silica sheets (one at the top and another
at the bottom)
-nH2O between the molec
CEE 302. Lecture 6. Soil Compaction
Study online at quizlet.com/_8nyqb9
According to
Proctor,
compaction
of soil is a
function of (4
pts)
Dry unit weight • Compactive effort • Water
content • Soil type
14.
Proctor
Test (def
and
procedure)
15.
Relative
Compaction
formula
As the
compactive
effort is
increased
(water
content )
soil's optimum moisture content decreases
16.
Soil
Compaction
- Why? (6
pts)
No site is ideal, 2. Increase strength, 3.
Decrease compressibility, 4. Decrease
permeability, 5. Control seasonal volume
change, 6. INEXPENSIVE compared to
remediation or replacement
Coarse
grained soils
specifications
(water)
no water criterion
17.
Soil
structure
by water
content
- Flocculated (low water content) - Orderly
arrangement or Dispersed (high water content)
4.
compaction
curve (def)
dry unit weight vs water content
5.
Compactive
effort (def)
energy (# of passes, weight of roller) (FIELD)
or calculated based on type of equipment &
procedure (LAB)
18.
Sr as w and
yd formula
6.
dry unit
weight
(formula)
7.
Effect of Soil
Type on
Compaction
• Coarse-grained soils primarily affected by
gradation • Fine-grained soils primarily
affected by plasticity
19.
total unit
weight
(formula)
8.
Field
Compaction
Control Tests
Sand Cone Test • Balloon Test • Water/Oil
Test • Drive Tube Test • Nuclear Density
Gauge - Dynamic Cone Penetrometer
9.
Mechanism of
Soil
Compaction
Aplly load, more load, add more soil to the
block
10.
Method
Specification
Specific Roller (model) - speed - frequency
of vibration (if applicable) - number of
passes - Add/remove water from borrow
20.
Increase in w tends to "lubricate" → easier to
reorient particles into a denser configuration
Modified
Proctor Test
vs Standard
Proctor Test
weight, height, layers, energy
Water
Content:
Dry of
optimum
21.
Water starts replacing soil particles in mold.
12.
Not allowed
for
compaction
fines±coarse
- Medium to high plasticity soils (LL > 35 40; PI > ~ 20) - Organic materials, topsoil,
roots, branches, etc. - Cobbles or boulders
(they can nest) - Construction debris, trash,
or refuse - Frozen soils
Water
Content:
Wet of
optimum
13.
optimum
water content
(def)
is where Maximum dry unit weight
1.
2.
3.
11.
hammer hits soil with different water content
22.
yd as w and Sr formula
23.
Zero air voids curve (def)
Maximum possible soil density for any specified water content
Chapter 1: Historical Perspective Chapter 2: Origin of soil and
grain size
Study online at quizlet.com/_7w9wmp
1.
Hydrometer analysis quiz
What types of soils are recommended for the hydrometer analysis?
Fine Grain
For what size soils is this test recommended?
Fine < 0.075 mm
How does the temp. effect the data analysis?
Temp. affects viscosity of the fluid therefor affects settling
What kind of dispersant is used?
Calgon solution
Why hydrometer tests are not recommended for sands?
Particles are too small
What is the name of the governing theory for this test?
Stokes law
How much % of solution of calgon ( sodium hexametaphosphate) did you use?
4%
For how long the soil sample have to be soaked in the solution of dispersant?
8-12 hours
What is F_z and F_m ?
Zero correction
Minuscus correction
2.
InClass
quiz
What is the geotechnical purpose of compaction of soil? What are the four field compaction verification methods?
Increase density of the soil.
1. Sandcone
2. Oil
3. Balloon
4. Nuclear (we use this)
What kind of engineering improvement does compaction have on the compacted soil in terms of strength settlement
and permeability?
Reduces soil settlement
Increases strength
Decrease permeability
What are the 3 soil classification systems? which one is widely used in engineering community?
USDA
AASHTO
USCS (Widely used)
Name the stabilizer which is suitable for clays and sands?
For clays we use lime since it lowers PI.
For sand we use cement since it binds particles together.
G - Gravel
S - Sand
M - Silt
C - Clay
W - Well graded
P - Poorly graded
H - High plasticity
L - Low plasticity
Define plasticity Index. How does plasticity index relate to swell/shrink potential of the soil?
Measures plasticity of the soil.
PI = LL-PL
Higher PI = Shrink and swell easily
Low PI = less potential to swell and shrink
Define shrinkage limit, activity, and sensitivity.
Shrinkage: Soil shrinks as moisture is gradually lost from it. With continuing loss of moisture, a stage of equilibrium is
reached at which more loss of moisture will result in no further volume change (Figure 4.9). The moisture content, in
percent, at which the volume of the soil mass ceases to change is defined as the shrinkage limit. This is when it goes
from semi-solid to solid state.
Activity: ratio of the PI/% Clay fraction in the soil
Sensitivity: How sensitive is the clay. Undisturbed. Measures the loss in the strength of soil as a result of remoulding
Should high or low plasticity soils be used on house pad, landfill lining, lake bottom, and pavement subgrade?
House pad: Low PI
Landfill lining: High PI
Lake bottom: High PI
Pavement sub grade: Low PI
Write the formula to find dry unit weight when e, w, and S are given:
γ_d = [(G_s + Se)ρ_w]/(1+e)
What is relative density?
D_r = (e_max - e)/(e_max - e_min)
What are the 3 phases of a soil sample? Under what circumstance would it become a two phase material?
Solid, Water, and air.
Saturated.
What will be the typical range of void ratio of a clay sample and a sand sample?
0.39
How deep of the earth from the surface is geotechnical engineer typically concerned about?
300 ft
Name the four particle size classification systems? Which one is the industry standard?
Sand
Silt
Clay
Gravel
AASHTO
Why is it that the faults in California contribute to earthquake and not the faults in the Houston area? What problems
contributed by the faults in Houston that engineer needs to be concerned about?
California has rock plates and Houston has soft plates.
Problems include constant motion.
3.
Mechanical
analysis
Mechanical analysis is the determination of the size range of particles present in a soil, expressed as a
percentage of the total dry weight. Two methods generally are used to find the particle-size distribution of soil:
(1) sieve analysis—for particle sizes larger than 0.075 mm in diameter, and
(2) hydrometer analysis—for particle sizes smaller than 0.075 mm in diameter.
Sieve analysis consists of shaking the soil sample through a set of sieves that have progressively smaller
openings. U.S. standard sieve numbers and the sizes of openings are given.
To perform this test:
1. You will find or you well be given the mass of soil retained for each sieve.
2. Calculate the % retained on each sieve. You do this by using the following equation for each sieve:
P₁ = W₁/W*100
P₂ = W₂/W*100
3. Then calculate the cumulative % retained. This is the % weight retained on that sieve plus all % weight retained
of all the sieves above it. Total % amount of soil which could not pass the particular sieve. In other words this %
amount of soil has grain size greater than the sieve #. To do this:
C₁ = P₁
C₂ = P₁ + P₂
C₃ = P₁ + P₂ + P₃
and so on ...
4. Then calculate the % finer. This is the % amount retained in a sieve which is just:
100 - C₁
100 - C₂
100 - C₃
and so on ...
Hydrometer analysis is based on the principle of sedimentation of soil grains in water. When a soil specimen is
dispersed in water, the particles settle at different velocities, depending on their shape, size, weight, and the
viscosity of the water. For simplicity, it is assumed that all the soil particles are spheres and that the velocity of
soil particles can be expressed by Stokes' law.
Sieve analysis gives the intermediate dimensions of a particle; hydrometer analysis gives the diameter of an
equivalent sphere that would settle at the same rate as the soil particle. This analysis is performed for soil sizes
smaller than 75 micrometers. They cannot be put through a sieve analysis since smaller particles carry charges
on their surface and have a tendency to stick to the sieve surfaces and to each other.
Now you can plot the grain distribution curve. x axis will be the grain size diameter in mm and the y axis is the
% finer by mass calculated in step 4. These curves help us estimate soil properties. A particle-size distribution
curve can be used to determine the following four parameters for a given soil:
a. Effective size (D₁₀): : This parameter is the diameter in the particle-size distribution curve corresponding to
10% finer. The effective size of a granular soil is a good measure to estimate the hydraulic conductivity and
drainage through soil.
b. Coefficient of Uniformity is a numerical expression of the variety in particle sizes in mixed natural soils.
C_u = D₆₀/D₁₀
c. Coefficient of gradation/curvature(Cc) describes the general shape of gradation. This parameter is defined as:
C_u = (D₃₀)²/(D₁₀*D₆₀)
These values could helps us classify soil:
If C_u > 4 & 1 < C_c < 3 Well graded gravel
If C_u > 6 & 1 < C_c < 3 Well graded sand
If none are satisfied then soil is poorly graded.
D₆₀ is the diameter of soil particle below which 60% amount of particles are finer than this size, the remaining
40% are coarser. D₆₀ could be any size particle, just means that 60% of the soil is made of this size particles. In
other words 60% of soil mass has particles which all have size < D₆₀. Whatever that size may be. Same thing
applies for D₁₀ and D₃₀. For examples if D₆₀ = 0.45 mm then 60% of soil is smaller than 0.45 mm and 40% are
coarser or larger tan 0.45 mm.
We can also use the graph itself to classify soil:
If more than 50% of soil material has particle size > 0.075 mm soil is coarse grain if its < 0.075 mm soil if fine
grain. Just find the corresponding diameter at a 50% finer if that diameter is > than 0.075 mm then its coarse
grain soil.
4.
A well graded curve contain almost all particles of different sizes. Uniformly graded soil curves are steep and
include a short range of particle sizes. If a curve has particle sizes that arent represented by the curve or has
absent particle sizes then its poorly graded soil. There must me a deficiency or excess of certain particle sizes or
most particles are the same size. You can see this by taking any 2 particles sizes and see how much of the soil is
between those particle sizes. Gap graded soil has a gap between the distribution of particles. Such soils miss the
amount of soil between two certain particle sizes. Graphs can tells use the type of soil and the % of the types of
soils included in the sample as shown on your notes.
Sieve Analysis Test quiz
For which type of soil will you recommend the sieve analysis?
Coarse
At what condition of the soil will you start the sieve analysis?
Dry
How will the moisture in the soil affect the sieve analysis?
Moisture will create lumps will change size
What is the curve you plot from the sieve analysis?
GSD
What was the largest sieve opening size in mm you used?
4.75 mm
What was the smalles sieve opening size in mm that you used 0.075 mm
Did you have soil finer than sieve no. 200?
Yes
What is the sieve No. of 0.075 mm opening sievce?
200
5.
Weight
Volume
Relationships
V_s = volume of soil solids
V_v = volume of voids
V_w = volume of water in the voids
V_a = volume of air in the voids
W_s = weight of soil solids
W_w = weight of water
Note: Volume of water will always be less than the volume of voids
Total volume of soil sample: V_s + V_v = V_s + V_w + V_a
Total weight of sample:
W = W_s + W_w
weight of air is just zero.
Void ratio (e) : ratio of the volume of voids to the volume of solids. Not represented as a %. Loose soil give
higher void ratio and dense soil gives small void ratio.
e = V_v/V_s
Porosity (n): ratio of the volume of void to the total volume. Usually expressed as %:
n = V_v/V * 100
Degree of saturation (S) : ratio of the volume of water to the volume of voids. How much empty space
presented in the soil sample is filled with water. If all pores are filled with water the soil is fully saturated. If no
water is present soil is dry. If its partially filled its partially saturated soil sample. Will never be greater than
100%.
S = V_w/V_v
Common relation between void ratio and porosity:
e = n/(1-n)
n = e/(1+e)
Density equations:
ρ = M/V
ρ_d = M_s / V
ρ = density of soil (kg/m³)
ρ_d = dry density of soil (kg/m³)
M = total mass of soil sample (kg)
M_s = mass of soil solids in the sample (kg)
V = total volume (m³)
Relative density: used to indicate the in situ denseness or looseness of granular soil:
D_r = (e_max - e)/(e_max - e_min)
e_max = void ratio of the soil in loosest state
e_min = void ratio of soil at densest state
e = in situ void ratio of soil.
Specific gravity (G_s) is defined as the ratio of the unit weight of a given material to the unit weight of water.
water content (w) is the ratio of weight of water and weight of solids. Usually represented as a %.
w = W_w/W_s * 100
Units weight γ is weight per unit volume:
Chapter 3: Weight-Volume Relationships
Study online at quizlet.com/_5szfgf
1.
Activity, defined as the slope of line
correlating plasticity index and percent
finer than 2μ, is used as an index for
_____________.
identifying
the swelling
potential of
clay soils.
2.
The A-line in the plasticity chart is
represented by the equation _________________.
PI = 0.73(LL 20)
3.
The A-line in the plasticity chart
separates_____?
inorganic
clays from
the inorganic
silts.
pg 83
4.
As per the liquid limit test (ASTM D-4318),
the relation between water content and log
N
is approximated as _________________.
straight line.
pg 74
5.
Dense uniform sand can have a void ratio
of___________.
0.5
pg 62
6.
For clean sand samples, emax and emin are
related as _____________.
emax ≈ 1.6
emin
A fully saturated soil is a ___________.
two-phase
system
consisting of
soil solids
and water.
7.
15.
True / False
True: Degree of
saturation lies
between 0 and
100%.
AND
Void ratio can be
greater than unity.
AND
Porosity lies
between 0 and
100%.
False:
Water content is
always less than
100%.
16.
Volume Relationships
Void Ratio
Porosity
Degree of
Saturation
17.
The water content of soil at the point
of transition from semisolid to plastic
state is __________.
plastic limit
pg 73
18.
Weight Relationships
Moisture Content
Unit Weight
Dry Unit Weight
8.
If liquid limit = 36%, and plasticity index =
12%, then plastic limit will be
PI = LL - PL
24%
19.
Which of the following is not a
volume relationship?
water content
9.
If the specific gravity of soil solids is 2.67,
and water content is 32% for a given soil, its
void ratio will be?
e = w*Gs / S
Assume
degree of
saturation (S)
=1
0.85
20.
Which of the following is not
represented as a percentage?
void ratio
21.
Which one of the following soils can
have in situ moisture content greater
than its liquid
limit?
sensitive clayey
soils
pg 82
10.
If void ratio of a soil is 0.2, then its porosity
will be?
n = e / (1+e)
16.7 %
11.
Porosity of a soil is defined as ___________.
the ratio of
volume of
voids to the
total volume.
12.
The relative density of dense granular soils
ranges from_____________.
70 to 85%
pg 70
13.
A representative soil specimen collected
from the field weighs 1.9 kN and has a
volume of
0.12 m3. The water content as determined in
the laboratory is 13.5%. What will be the dry
unit weight of the soil?
Yd = Y / (1+w)
Y = 1.9/0.12
w = .135
Final Answer
= 13.9 kN/m^3
14.
Soil deposits that are heavily
overconsolidated may have a natural
moisture content less than the plastic limit.
In that case, the liquidity index, ______________.
LI < 1
pg 82
Sec 3.2 Soil composition for weight-volume relationships
Study online at quizlet.com/_80w404
1.
degree of saturation
S
Vw/Vv x 100
21.
specific gravity
equation
voids are completely filled with air
2 phase medium (solid and air
particles)
Gs = density solid particle / density
water
Gs = specific weight solid particle /
specific weight water
2.
dry soil
22.
S range
0 to 100
3.
dry unit weight
gamma(d) = Ws/V
23.
unit weight
gamma - W/V
4.
if S is 0
dry soil
24.
V
5.
if S is 100
fully saturated soil
total volume of the soil sample
= Vw+Vs+Va
6.
if soil is fully
saturated
S = 1 or 100% -e = w(sat) * Gs
25.
Va
volume of air in the soil sample
26.
void ratio
7.
moist unit weight
gamma = (Ws + Ww(moist)) / V
e
Vv/Vs
8.
moisture content
w
Ww/Ws x 100
27.
void ratio for poorly
graded soil
high because loosely compact
9.
moisture content for
clay
5-300%
takes long time for water to seep out
28.
void ratio for well graded soil
low because densely compacted
10.
moisture content for
sand
10-30%
29.
Vs
volume of solids in soil sample
30.
Vw
volume of water in the soil sample
11.
partially/unsaturated
soil
voids are partially filled with water
and the rest is with air
3 phase medium
31.
W
total weight of the soil sample
Ww + Ws
32.
Wa
12.
phase diagram
weight and volume of each
component of soil
weight of air in the soil sample
said to be 0
33.
13.
porosity
n
Vv/V
water table and soil
saturation
saturated soil below the water table
dry soil above the water table
34.
weight of solids
Ws = (Gs) (gamma water)
14.
range of Dr
0 to 100%
35.
weight of water
Ww = (w)(Gs)(gamma water)
15.
relationship
between n and e
n = e / (1+e)
36.
Ws
weight of solids in the soil sample
16.
relative density
Dr
a measure of
compactness/denseness/physical
state of granular soils (sand and
gravel)
- qualitative description of granular
soil deposits
37.
Ww
weight of water in the soil sample
17.
saturated soil
voids are completely filled with water
2 phase medium (water and solid
particles)
18.
saturated unit
weight
gamma(sat) = (Ws + Ww(sat)) / V
19.
soil combination of
solids
water
air
20.
specific gravity
Gs
the ratio of weight of a unit volume of
a material to the weight of a unit
volume of water
weight and volume relationships soils
Study online at quizlet.com/_7yrwb1
1.
degree of saturation
ratio of volume of water to volume of voids
2.
degree of saturation
Vw/Vv*100
3.
dry unit weight
Ms/V
4.
Liquid Index
(w-PL)/(LL-PL)
5.
plasticity index
=LL-PL
6.
porosity
volume of voids to total volume
7.
porosity
=Vv/V*100
8.
specific gravity of solids
ratio of unit weight of solids to unit weight of water
9.
Unit weight
M/v
10.
void ratio
Vv/Vs
11.
void ratio
volume of voids/volume of solids
12.
water content (dry)
ratio of weight of water to weight of solids
13.
water content (wet )
ratio of weight of water to weight of solids+water
142 Weight Volume Relationship
Study online at quizlet.com/_78b7lk
1.
Assumption 2
total volume = 1
2.
Assumption when given SG
volume of solids = 1
3.
buoyant density
saturated density - density of water
4.
buoyant unit weight
unit weight sat - unit weight of water
5.
degree of saturation (s%)
volume of water/volume of voids
6.
density of solids
mass of solids/volume of solids
7.
dry density
mass of solids/total volume
8.
dry density
total density/(1+w%)
9.
dry unit weight
weight of solids/total volume
10.
moisture content (w%)
weight of water/weight of solids
11.
Porosity (n)
volume of voids/total volume
12.
saturated density
density when volume of air = 0
13.
specific gravity
unit weight of soil/ unit weight of water
14.
specific gravity
density of soil/density of water
15.
total density (moist density)
total mass/total volume
16.
total unit weight (moist unit weight )
total weight/total volume
17.
unit weight of solids
weight of solids/volume of solids
18.
void ratio (e)
volume of voids/volume of solids
Soil Mechanics - Weight-Volume Formulas
Study online at quizlet.com/_4qmyml
1.
dry density (ρd)
2.
Dry unit weight (Ɣd)
3.
Porosity, n
Ws/Vt
OR
ρ / (1+w)
or Vv/Vt
4.
Saturation, S
or Vw/Vv
5.
Specific Gravity (Gs)
6.
Void Ratio, e
or Vv/Vs
7.
Water content, w
8.
Wet unit weight (Ɣw)
Ww/Ws
Ch. 3 (Weight-Volume Relationships and Plasticity)
Study online at quizlet.com/_79upsg
1.
Activity
(A)
The PI of a soil increases linearly with the percent of clay sized fraction present in it
2.
Atterberg
Limits
A set of values of MC maximum or minimum units that define the consistency of soils
3.
brittle
solid
At very low MC, soil behaves more like a _______.
4.
Fall Cone
Method
Defines LL as the MC at which a standard cone of apex angle 30 degrees and weight of 0.78 N will penetrate a distance
of d=20mm in 5 sec when allowed to drop from a position of point contact with the soil surface
5.
flow
curve
the relation between MC and log N is approximated as a straight line known as
6.
liquid
When the MC is very high, the soil and water may flow like a ______.
7.
Liquidity
Index (LI)
-the relative consistency of a cohesive soil in the natural state (a ratio)
= (w-PL)/(LL-PL)
sensitive clay....... >1
heavily over consolidated......... <0
8.
Liquid
Limit
The MC at the point of transition from the plastic to liquid state.
9.
Liquid
Limit Test
-Soil is placed in the cup
-A groove is cut at the center of the soil pat, using a saturated grooving tool.
-The cup is lifted and dropped from a height of 10 mm
-The MC required to close a distance of 12.7 mm along the bottom of the grove after 25 blows is the LL
10.
Plasticity
Index (PI)
range in water content between PL and LL (plastic)
= LL - PL
11.
Plastic
Limit
The MC at the point of transition from semisolid to plastic state
12.
Plastic
Limit
The minimum moisture content at which the soil can be rolled into a thread 3.2 mm in diameter without crumbling and is
determined by trial and error.
13.
shrinkage
limit
The MC at which the transition from a solid to semisolid takes place
14.
shrinkage
limit
The MC at which the volume change of the soil mass ceases
= Winitial(%) - deltaW(%)
15.
shrinks
A soil mass _______ as moisture is gradually lost from the soil.
(but there is an equilibrium point)
16.
soil block
used to develop weight-volume relationships (diagram)
Chapter 3: Weight Volume Relationships (Study Guide)
Study online at quizlet.com/_7jpv10
1.
A dry soil must have 0% water content.
True
2.
A dry soil must have zero degree of saturation.
True
3.
Moisture content must be less than 100%.
False
4.
Porosity of a soil can exceed 100%.
False: Nothing would be there.
5.
Void ratio can be greater than 1.
True
6.
When a soil sample is obtained under the ground water table, the degree of saturation of the
sample is 100%.
True
7.
When a soil sample is obtained under the ground water table, there is no air in the sample.
True: This is an assumption we
make.
Weight-Volume Relationships (Unit 2)
Study online at quizlet.com/_6vhbmo
1.
Buoyant unit weight/density
saturated unit weight/density minus density of water
2.
Degree of saturation (S)
volume of water over volume of voids (expressed as a percent)
3.
Dry unit weight/density
weight/mass of dry soil per unit total wet soil volume
4.
Porosity (n)
volume of voids over total wet volume of soil
5.
Relative density
difference of e_max and e divided by difference of e_max and e_min
6.
Saturated unit weight/density
total weight/mass of solids and water per unit total volume of water and solids
7.
Total unit weight/density
weight/mass of wet soil per unit total we soil volume
8.
Unit weight/density of solids
weight/mass of dry soil (solids) per unit volume of solids only
9.
Void ratio (e)
volume of voids over volume of solids
10.
Water content (w)
mass of water per unit mass of solids
Soil Mechanics Test 1
Study online at quizlet.com/_80uta4
1.
AASHTO classifies soil based on
its ______
suitability
2.
A-line and U-line can be used for
determining the _____
shrinkage limit
3.
____ and ____ soils are deposited
beneath lakes or oceans
Lacustrine and Marine
4.
__________ are compactor used for
proof rolling of subgrade and
finishing (sand and clay)
Smooth wheel rollers
5.
_______ are field compactors that
are effective for clayey soils
Sheepsfoot rollers
6.
Are organic or inorganic soils
more desirable for engineering
properties?
inorganic
The volume of the test hole is
the volume of the cylinder
7.
_________ are the limiting moisture
contents that separate the 4 finegrained soil states
Atterberg Limits
While this method is faster
than the sand method, it is
slightly less precise
8.
As the compaction effort
increases, the maximum dry unit
weight ______
increases (positive
relationship)
9.
Basalt is a type of ______ rock
...
10.
The blasting special compaction
technique
involves detonating
explosive charges at a
depth below the
surface in saturated
soil
11.
both repulsive and attractive
forces act between ____ particles
clay
12.
Clays have____ plasticity
high
13.
Coarse or fine-grained soils
generally exhibit desirable
engineering properties?
coarse-grained
14.
Cohesive soil can have three
different types of structures which
are:
- flocculated structure
- nonsalt flocculated
structure
- salt flocculated
structure
these types of structures effect
the bonds of soil
15.
Compacted clay liners enhance
______ of compaction and make the
interlift zone rough in order to
improve connection
efficiency
16.
Compaction improves the
engineering properties of soil by
1. _______ its strength
2. _______ its compressibility
3. _______ its hydraulic conductivity
4. _______ erosion resistance
1. increases
2. decreases
3. decreased
4. increases
17.
Compaction is one of the
most important aspects of
earthwork
---
18.
Conglomerate is a type of
______ that is solidified by
pressure and cementing
action
sedimentary
19.
Cu stands fro the ______
uniformity coefficient
20.
Describe the Drive
Cylinder Test:
use a mallet and dry cylinder
to excavate soil - measure the
weight of that soil
but it is good for silty and clay
soils
21.
Describe the Nuclear
Method for measuring dry
unit weight in the field
This method measures
radioactive isotope sources.
Dense soil absorbs more
gamma radiation than loose
soil
22.
describe the Sand Cone
Method
you measure the weight of a
sample of soil taken from a
test hole
fill the test hole with standard
Ottawa sand and calculate the
volume with the known unit
weight
23.
Dr stands for:
relative density
24.
The dynamic compaction
special compaction
technique
drops a heavy weight
repeatedly on the soil from a
height of 7.5 to 30.5 m.
The Fall cone method defines the LL as the
moisture content at which a standard cone
penetrates ____ mm in ___ seconds when
dropped from point contact with the soil
surface
20; 5
26.
The Fall cone method ma also be used for
plastic limits, however the cone must have a
mass of _____ N instead
2.35
27.
Field compaction requirement is specified in
terms of:
Relative
Compaction
28.
_______ field compactors are an effective
method for granular soils
vibratory
rollers
29.
_________ field compactors are effective for
sand and clay
Pneumatic
rubber-tired
rollers
30.
A fine-grained soil can be one of the
following four basic states based on its
_________: solid state, semisolid state, plastic
state, liquid state
moisture
content
31.
A fine-grained soil in a _____ state deforms
permanently but cracks
semi-solid
32.
A fine-grained soil in a _____ state will break
before it deforms
solid
33.
A fine-grained soil in a _____ state will
deform easily
liquid state
34.
A fine-grained soil in a _____ state will
deform without cracking
plastic state
35.
For Residual Sizes, grain size _______ with
depth
increase
36.
For _____ soils, the transition with depth from
soil to weathered rock to fresh rock is
typically gradual with no distinct boundaries
Residual
37.
Geologists classify soils into two major
categories:
1. Residual
Soils
2.
Transported
Soils
25.
38.
Gneiss is a type of ___ rock
metamorphic
39.
Granite is a type of ______ rock
igneous
40.
gravel and sands have _____ plasticity
no
41.
High LI means the soil is potentially
unstable
42.
a high moisture content in fine-grained soils
will result in a ____ consistency
soft
43.
High relative density soils (Dr=85-100%) are
classified as
very dense
44.
High ______ suggests swelling and shrinking
problems, high settlement and low strength
PI
45.
honeycomb structures show a _____
void ratio
large
46.
How do we increase dry unit
weight?
1. Reduce the void
ratio
2. overcome friction
at particle interface
to bring particles
closer
3. apply eternal
energy with
appropriate amount
of lubricant
47.
Hydrometer and Sieve Analysis
results are plotted on a ____________
scaled
semi-log
48.
the important parameters of the
proctor curve are:
1. maximum dry unit
weight
2. optimum moisture
content
49.
Inorganic soils form from:
weathering of rocks
50.
_____ in soil acts as a softening
agent during compaction
moisture
51.
_______ is a measure of
compactness/denseness/physical
state of granular soils (sand and
gravel)
relative density, Dr
52.
_____ is an indicator of relative
consistency of cohesive soil in the
natural state
Liquidity Index
53.
_____ is the densification of soil by
removal of air using mechanical
energy
compaction
54.
The ______ is the diameter
corresponding to 10% finer, and is
useful to estimate hydraulic
conductivity
effective size
55.
_______ is the measure of the range
of moisture contents that
encompasses the plastic state
plasticity index
56.
_______ is the percent of particles
that are smaller than a particular
diamter
percent finer
57.
____________ is the ratio of weight of a
unit volume of a material to the
weight of a unit volume of water
specific gravity
58.
______ is used as an index for
identifying the swelling potential of
clay soils
Activity
59.
LI < 1 means the natural moisture
content is less than the _____ and its
a heavily consolidated soil
PL
60.
LI > 1 means natural moisture
content is greater than the ___.
These soils can be transformed to
viscous liquid.
LL
61.
Limestone is a type of ______ that is
solidified by cementing action
sedimentary
62.
The ________ limit is the moisture
content at which a soil begins to
behave as a liquid material
liquid
63.
The ______ limit is the moisture
content at which no further volume
change occurs with further reduction
in moisture content
Shrinkage
The ______ limit is the moisture
content at which soil begins to
behave as a plastic material
plastic
The liquid limit is defined as
moisture content which requires _____
blows to close a groove of ______ mm
when the brass cup is dropped by a
cam from a height of _____ mm
according to the Casa Grande
Method
25; 12.5; 10
a low moisture content in finegrained soils will result in a ____
consistency
hard
67.
Low relative densities (Dr= 0-15%)
are classified as:
very loose
68.
The major difference between silts
and clays may not be their particle
sizes, but their physical and
chemical structures for geotechnical
engineering applications: true or
false
true
69.
Marble is a type of __ rock
metamorphic
70.
The _____ method to measure the LL
estimates the liquid limit based on a
single trial and is generally valid for
20<N<30
one-point method
The modified proctor test is useful
when compaction needs to be done
for soil that will hold larger load
(aircrafts and trucks) because
the modified test is
designed to better
represent field
condition, and uses a
heavier hammer with
a larger drop, but the
same mold
64.
65.
66.
71.
72.
Most common minerals in soil have a
specific gravity between ___ and ___
2.6 and 2.8
73.
most field compaction is done with rollers,
including:
1. smoothwheel rollers
2. pneumatic
rubber-tired
rollers
3.
sheepsfoot
rollers
4. vibratory
rollers
74.
On the plasticity chart, the __-line is the
upper limit of the relationship between PI
and LL
U
75.
On the plasticity chart, the ____-line
separates the inorganic clays from the
inorganic silts
A
76.
Organic soils form from
decay of
vegetation
77.
_______ particles have very high specific
surface values because they have a very
small thickness relative to their length
flaky
78.
______ particle's surfaces carry small negative
electrical charge that will attract the end of
water molecules, therefore a lot of water
may be held as adsorbed water within a
clay mass
flaky
79.
Plastic limit is measured as the moisture
content at which the soil crumbles when
rolled into threads of ______ in
1/8
80.
Quartzite is a type of __ rock
metamorphic
81.
_______ relates the moisture content of the
soil to the LL and PL of the same soil
Liquidity
Index
82.
Relative Compaction is measured in terms
of dry unit weight from the field and the lab
---
83.
A relatively large Cu (uniformity coefficient )
means the soil is ___________
well-graded
84.
__________ sands are considerably less porous
than well sorted ones
poorly
sorted
85.
Sandstone is a type of ______ that is
classified as sand solidified by pressure and
cementing action
sedimentary
86.
Schist is a type of __ rock
metamorphic
87.
Shale is a type of ______ that is classified as
silts or clays solidified by pressure and
cementing action
sedimentary
88.
silts have _____ plasticity
low
89.
Slate is a type of __ rock
metamorphic
90.
Soil is compacted in layers of
approximately _____ inches, but can
vary based on soil type (thicker
layers can be used for ______ soils)
8; granular
91.
soil is compacted in _____ or layers
lifts
92.
_______ soil means that the voids are
filled with water and air
partially/unsaturated
soil
93.
_____ soil means the voids are
completely filled with air
dry
94.
_____ soil means the voids are
completely filled with water
saturated
95.
Soils are formed by:
weathering rocks
that were exposed
to mechanical and
chemical actions
107.
a _____ structure is a type
of cohesionless structure
where fine sand and silt
form arches.
honeycomb
108.
True or False: Particle
shape has significant
influence on the physical
properties of soil?
true
109.
Type of soil formed when
the rock weathering is
faster than the transport
process and much of the
resulting soil remains in
place
Residual Soils
110.
Type of soils that are
formed by the deposition
of sediments that have
been transported from
their places of origin by
various agents
Transported Soils
111.
uncontrolled (or
uncompacted) fill may
lead to:
1. differential settlement
2. low strength
3. rapid water flow or ponding
112.
The USCS system is an
all-purpose system and
therefore does not rate
soils from good to bad
---
113.
The vibroflotation special
compaction technique:
contains a weight that vibrates
horizontally. It has opening at
the top and bottom for water
jets and the unit compacts a
cyinder of about 2m radius
each time it is lowered
96.
_____ soils are transported by
glaciers
Glacial
97.
_____ soils are transported by gravity
colluvial
98.
____ soils are transported by rivers
and streams
Alluvial
99.
_____ soils are transported by wind
Aeolian
100.
______ soils generally exhibit
undesirable engineering properties
because they have lower shear
strength, compressibility, expand
(wetting) and shrink (drying) when
moisture level varies, and because
they develop larger lateral pressure
and not good for retaining wall
backfills
fine-grained
(specifically clay)
101.
______ soils generally make for good
foundation material
Coarse-grained
114.
the void ratio of soil at
the project site is:
e
102.
______ soils generally make for good
retaining wall backfills
Coarse-grained
115.
the void ratio of the soil
in the densest state
emin
103.
_________ soils have a relatively large
bearing capacity
Coarse-grained
116.
the void ratio of the soil
in the loosest state
emax
104.
Soils with a large ______ content
retain plastic state over a wide
range of moisture content, and thus
have large plasticity index. The
opposite is true for silt
clay
117.
The Water Ring Test for
measuring dry unit weight
in the field is used when:
soil consists of cobbles and
small boulders
118.
high
Strength of metamorphic rock
depends on:
the level of
metamorphism and
original parent rock
Weak bonds mean there
will be a _________ swelling
index (activity)
119.
The weakest type of
bond is ______
a van der Waals bond
A ________ structure, a type of
cohesionless structure, is a more
stable structure
single grained
105.
106.
120.
weight and distance dropped
of standard proctor test
& of modified proctor test
Standard: 12 in and 5.5 lb
Modified: 18 in and 10 lb
both: 25 blows
121.
What are clay and silt
distinguished by in practice?
plasticity
122.
What are four factors that
affect lab compaction?
1. moisture content
2. compaction effort
(energy supplied)
3. method of compaction
4. soil type (gradation, clay
minerology, etc.)
123.
What are four methods for
determining the dry unit
weight in the field?
1. Sand Cone Method
2. Drive Cylinder Method
3. Water ring Method
4. Nuclear Method
124.
What are the two types of lab
tests for compaction?
1. Standard Proctor Test
2. Modified Proctor Test
(which uses more energy
than the proctor test)
125.
What are three special
compaction techniques
1. vibroflotation
2. dynamic compaction
3. blasting
126.
What are three ways to
determine moisture content
in the field?
1. Stir-fry
2. Microwaving
3. speedy moisture tester
127.
What do we use to measure
the degree of compaction?
the dry unit weight
128.
What has greater shear
strength? rounded or angular
particles?
angular
What kind of rock has
excellent engineering
properties when
unweathered?
Igneous
129.
130.
What kind of rock is formed when
fragmented rock particles and remains
of certain organism are solidified by
overburden pressure, cementation, or
chemical action?
Sedimentary Rock
131.
What must we keep in mind before we
begin compaction (specs)?
1. type and weight
of compactor
2. number of
passes and speed
of pass
3. lift thickness
4. maximum
particle size
132.
What must we keep in mind when
determining the end product of
compaction (specifications)?
1. required relative
compaction
2. the fact that the
contractor can use
any method-as
long as the endstate is achieved
133.
What properties are the compaction
specifications concerned with?
1. strength
2. compressibility
3. hydraulic
conductivity
4. volume change
due to freezethaw or wet-dry
cycling
134.
What soil is cohesive?
clay
135.
What soils are not cohesive?
silt/sand/gravel
136.
What three controls can we have on
compaction?
1. compaction
effort (energy)
2. soil type
3. moisture
content
137.
What three ways are compactors and
rollers used for compaction
1. weight
2. coverage area
3. vibration
138.
When compaction effort increases, so
does the measured maximum dry unit
weight and the optimum moisture
content decreases
TRUE
139.
When the coefficient of gradation is
between 1 and 3, this means there is a
_______ curve
smooth
140.
Which classification system is
universally accepted?
USCS
141.
Which kind of rocks are formed when texture, structure, or mineral composition of igneous
of sedimentary rocks are changed as a result of heat, pressure, shear?
metamorphic
142.
Which kind of rock varies in engineering properties depending on its strength (soft to hard)
sedimentary
143.
Which kinds of rocks are formed when molten magma solidify on or below the ground
surface
Igneous
144.
Why do we compact in lifts?
to ensure uniform engineering
properties and remove defects
Sec 3.3: soil composition plasticity and structures of soil
Study online at quizlet.com/_80w8b3
1.
2 types cohesive
soil structures
dispersed structure
flocculated structure
2.
2 types of
flocculated
structure
nonsalt flocculated
salt flocculated
3.
3 methods for
determination of
liquid limit
casagrande method
one-point method
fall cone method
4.
3 types of clay
structures
kaolinte, illite, smectite
- have different ratios of aluming and
silica
4 basic states of
fine grained soil
solid state
semisolid state
plastic state
liquid state
6.
activity
used as an index for identifying the
swelling potential of clay soils
7.
A-line and U-line
used
to determine SL
8.
A-line of
plasticity chart
separates inorganic clays from inorganic
silts
9.
Atterberg limits
limiting moisture contents that separates
the 4 states of fine grained soils
10.
Atterberg limits
used in
soil classification and empirical
correlations to determine other soil
properties such as swelling potential,
compressibility, permeability, and shear
strength
11.
basic structure of
cohesive soils
depends on
types of forces acting between particles
12.
calculation of PI
LL - PL
13.
casagrande
method
soil sample is placed in te brass cup
groove is then cut in soil sample using a
tool
brass cup is then dropped until groove
closes
5.
14.
15.
clays with a large
clay content
consistency of
fine grained soil
between plastic
limit and liquid
limit
retains plastic state over small range of
moisture content, so have small
plasticity index
16.
consistency of
fine grained
soil between
shrinkage limit
and plastic
limit
semisolid state
17.
consistency of
fine grained
soil in below
shrinkage limit
lowest MC
solid state
18.
consistency of
fine grained
soils
degree of firmness (soft, medium, or hard)
or physical state of fine-grained soils
varies with moisture content of the soil
19.
consistency of
fine grained
soils above
liquid limit
highest moisture content
liquid state
20.
dispersed
structure
individual clay particles slowly settled by
random motion (Brownian motion)
particles are parallel to each other
21.
factors
affected by
plasticity of
the soil
swelling and shrinking problems
high settlement
low strength
22.
fall cone
method
defines the liquid limit as the moisture
content at which a standard cone (apex
angle of 30 deg and weight of 0.78 N)
penetrates 20mm in 5 seconds when
dropped from point contact with the soil
surface
23.
fall cone
method for PL
may be used as in the liquid limit, but using
a cone (similar geometry) with a mass of
2.35 N instead
24.
fined grained
soils
silts and clays
distinguished by a property called
plasticity
25.
flocculated
structure
higher void ratio
lighter structure
26.
flocculated
structure
...
27.
flow curve
relationship between moisture content and
log(N)
28.
high activity
value
lots of swelling occurs
29.
high fraction of
clay minerals
high plasticity, can result in
swelling/shrinking - if build on this, large
settlement and low strength of soil
30.
High LI
potentially unstable
plastic state
31.
high moisture
content
soft fine grained soil
32.
high moisture
content for
casagrande method
will be easy to close so have low
blow counts
33.
high PI
suggests swelling and shrinking
problems, high settlement and low
strength
34.
honeycombed
structure
fine sand and silt form arches
shows large void ratio
load carrying arches can easily
collapse when subjected to large
static load or vibration - result in large
settlement
(higher void ratio so weaker structure)
35.
if w = LL
LI = 1
36.
if w = PL
LI = 0
37.
illite
2:1 ratio
potassium ions
highly stable
most common clay mineral
K - strong bond
38.
important features
of plasticity chart
A-line
U-line
39.
kaolinite
1:1 ratio of alum:silica
hydrogen bonds
strong bonding between layers
no interlayer swelling
40.
LI greater than 0
natural moisture content is greater than
the LL
these soils can be transformed to
viscous liquid (Norwegian quick clay)
liquid
41.
LI is indicator of
relative consistency of cohesive soil in
the natural state
42.
LI less than 0
natural moisture content is less than
the PL
heavily overconsolidated soils
semisolids
limits between
solid/semisolid
state and
plastic/liquid state
Atterberg limits
44.
liquidity index
LI
relates the moisture content of the soil
to the LL and PL of the same soil
45.
liquid limit
LL
moisture content (in%( at which soil
begins to behave as a liquid material
43.
46.
liquid limit
for
casagrande
method
defined as the moisture content which
requires 25 blows to close the groove of 12.5
mm, when the brass cup is dropped by a
cam from a height of 10mm
- difficult to adjust the moisture content to
satisfy both conditions (25 blows and 12.5
mm groove)
47.
liquid state
deforms easily
(highest moisture content)
48.
low moisture
content
hard fine grained soil
49.
low moisture
content for
casagrande
method
will take more blows to close the 25 mm gap
since it is stronger
50.
major
difference
between silts
and clays
may not be their particle sizes, but their
physical and chemical structures for
geotechnical engineering applications
51.
negative
charges
concentrated
at
the face
52.
N in flow
curve
the number of blows in the liquid limit device
for 12.5 mm groove closure
53.
nonsalt
flocculated
structure
edge (positive charge) - to - face (negative
charge) contact is formed and help by
electrostatic attraction
depending on size of flocculated structure,
the settlement velocity varies
54.
one point
method
estimates the liquid limit based on a single
trial
generally valid for 20<N<30
55.
overconsolidated
soil
experienced a lot of stress in the past
compared to the present
ex: glacier melting
56.
PI indicated
plasticity and other soil properties
(settlement strength)
57.
plasticity
charts
Atterberg limits of PI and LL used to classify
fine grained soils
58.
plasticity
index
PI
measure of the range of moisture content that
encompasses the plastic state
59.
plasticity of
clay
high plastic
60.
plasticity of
gravel
non plastic
61.
plasticity of
sand
non plastic
62.
plasticity of silt
low plasitc
78.
63.
plastic limit
PL
moisture content (in%) at which soil
begins to behave as a plastic material
types of forces that act
between clay particles
repulsive- due to negative
charges around clay particles
attractive- van der Waals force
79.
U-line of plasticity chart
upper limit of the relationship
between PI and LL
80.
volume change
volume increases when water is
added to the sample
plastic limit
definition
moisture content at which the soil
crumbles when rolled into threads of 1/8
in (3.2mm) in diameter threads
65.
plastic state
deformed without cracking
66.
positive charges
concentrated at
the edge
67.
salt flocculated
structure
salt reduces the inter particle repulsion
flocculation structure is formed due to
can der Waals
(salt helps to make it stronger)
68.
semisolid state
deforms permanently but cracks
69.
shear stress
strain at various
moisture content
increase moisture content, strength
change decrease
70.
shrinkage limit
SL
moisture content (in%) at which no
further volume change occurs with
further reduction in moisture content
71.
single grained
structure
void ratio varies with particle size range,
particle shape
more stable compared to honeycombed
structure
(lots of points of contact between
particles, less void ratio so stronger)
72.
SL
moisture content (in%) at which the
volume of the soil mass ceases to
change
73.
smectite
2:1
van der Waals bonds and exchangeable
ions
weak bonding
high specific surface
high swell potential
74.
soils with a large
clay content
retains a plastic state over a wide range
of moisture content, so have a large
plasticity index
75.
solid state
breaks before it will deform
(low moisture content, plastic
deformation)
76.
state of fine
grained soil
depends on
moisture content
77.
two types of
structures in
cohesionless soil
single grained structure
honeycombed structure
64.
Soil Mechanics - Chapter 2
Study online at quizlet.com/_33ftnn
1.
1. Angular
2. Subangular
3. Subrounded
4. Rounded
4 terms used by geologist to describe the
shape of bulky particles.
2.
1. BraidedStream
Deposits
2. Meandeing
Belt of Streams
Two Major Categories of Alluvial Soil
Deposits:
1. Bulky
2. Flaky
3. Needle
Shaped
The particle shape generally can be
divided into three major categories:
1. Coastal Areas
2. Glaciated
Regions
Organic Soil is most commonly found in
these two areas.
1. Compact
2. Windward
Side
3. Loose
4. Leeward Side
Fill in the blanks: The process tends to
form a _______________ sand deposit on the
____________________, and a rather ___________________
deposit on the ___________________, of the dune.
6.
1. Concave
2. Convex
Fill in the blanks: The soil from the bank is
continually eroded from the points where it
is ____________________ in shape, and is deposited
at points where the bank is ___________________in
shape.
7.
1. Discontinuous
Ferromagnesian
Reaction Series
2. Continuous
Plagioclase
Feldspar
Reaction Series
These are the two reactions classified by
Bowen.
1. Effective Size
2. Uniformity
Coefficient
3. Coefficient
of Gradation
The three soil parameters
1. Glacial Soils
2. Alluvial Soils
3. Lacustrine
Soils
4. Marine Soils
5. Aeolian Soils
5 classifications of transported soils
depending on their mode of transportation
and deposition.
1. Glacier Ice
2. Wind
3. Running
water of
Streams
4. Ocean Waves
Other physical agents that help
disintegrate rocks in mechanical
weathering
3.
4.
5.
8.
9.
10.
11.
1. Granite
2. Gabbro
3. Basalt
Three of the most common
types of igneous rock.
12.
1. Gravel
2. Sand
3. Silt
4. Clay
Four categories of Soil
according to size.
13.
1. Gypsum
2. Anhydrite
3. Rock Salt (NaCl)
Three examples of evaporites
14.
1. Ice
2. Water
3. Wind
4. Gravity
Four ways how weathering
products could be transported
15.
1. Igneous
2. Sedimentary
3. Metamorphic
Three basic types of rocks
16.
1. Kaolinite
2. Illite
3. Montmorillonite
Three important clay minerals
17.
1. Massachusetts Institute of
Technology
2. U.S. Department of
Agriculture
3. American Association of
State Highway and
Transportation Officials
4. Unified Soil Classification
System
Four organizations that
formulated their own SoilSeparate-Size Limits
18.
1. Sieve Analysis
2. Hydrometer Analysis
Two methods that are
generally used to find the
particle-size distribution of
soil
19.
1. Silica Tetrahedron
2. Alumina Octahedron
Two basic units composing
the aluminum silicates need to
form clay minerals
20.
1. Size
2. Shape
3. Chemical Composition
Three charareristics that
dictate the majority of the
physical properties of soil.
21.
1. Soluble Salts in
Groundwater
2. Organic Acids from
Decayed matter
These are some of the causes
of chemical weathering. (2)
22.
2.65
The specific gravity (Gs) of soil that calibrated
for hydrometers, for soils of other specific
gravity, it is necessary to make corrections
42.
Chemical
Sedimentary
Rock
Other kind of sedimentary rock that can
either have clastic or non-clastic texture
and formed chemically
23.
15 m^2/g
Specific Surface of Kaolinite
43.
24.
80 m^2/g
Specific Surface of Illite
Chemical
Weathering
25.
200 to
300%
The natural moisture content of organic soil
may range from ________________________
This type of weathering transforms the
original rock minerals into new minerals by
chemical reaction.
44.
Clastic Texture
Texture of Detrital Sedimentary Rock
26.
800 m^2/g
Specific Surface of Montmorillonite
45.
Clay Minerals
27.
Adsorbed
Water
The innermost layer of double-layer water,
which is held very strongly by clay
Are complex aluminum silicates composed
of one of two basic units.
46.
Clays
28.
Aeolian
Soils
Transported soil which is deposited by wind
Are defined as thos particles "which
develop plasticity when mixed with a
limited amount of water" (Grim, 1953)
Alluvial Soil
Deposits
These are derived from the action of streams
and rivers and can be divided into two major
categories.
47.
Clays
29.
30.
Alluvial
Soils
Transported soil formed through transportation
along running water and deposited along
streams
These are mostly flake-shaped
microscopic and submicroscopic particles
of mica, clay minerals and other minerals.
These are generally defined as particles
smaller than 0.002 mm.
48.
Collovium
The soil deposits formed by landslides are
called ________________
31.
Alumina
Octahedron
Each unit consists of six hydroxyls surrounding
and aluminum atom.
49.
32.
ASTM 152H
A type of hydrometer is placed in the soil
suspension at a time t, measured from the start
of sedimentation, it measure the specific
gravity in the vicinity of the bulb at a depth L.
Continuous
Plagioclase
Feldspar
Reaction Series
The reaction in which the minerals formed
have different chemical compositions with
similar crystalline structures.
50.
Creep
This occurs when residual soil on a steep
natural slope can move slowly downward.
33.
Attapulgite
Commonly used clay mineral for cleansing
51.
Delta
34.
Backswamp
Deposits
These are finer soil particles consisting of silts
and clays that are carried by the water farther
onto the floodplains
This forms where the stream enters the
lake, granular particles are deposited in
the area.
52.
Detrital
Sedimentary
Rocks
Rocks formed when the cementing agents
fill the spaces between the particles of the
existing rock
35.
Bowen's
Reaction
Principle
A principle that describes the sequence by
which new minerals are formed as magma
cools
53.
36.
BraidedStreams
Are high-gradient, rapidly flowing streams that
are highly erosive and carry large amounts of
sediment.
Diffuse Double
Layer
When water is added to clay, these cations
and a small number of anions float around
the clay particles.
54.
Dipole
A water molecule acts like a small rod
with a positive charge at one end and a
negative charge at the other end.
55.
Discontinuous
Ferromagnesian
Reaction Series
The reaction in which the minerals formed
are different in their chemical composition
and crystalline structure.
56.
Dispersing
Agent
Sodium Hexametaphosphate
57.
Dolomite
Is either formed by chemical deposition of
mixed carbonates or by the reaction of the
magnesium in water with limestone.
58.
Double Layer
Water
All of the water held to clay particles by
force of attraction.
37.
Breccia
In the case of conglomerates, if the particles
are angular, the rock is called __________________
38.
Brucite
Sheet
In some cases, magnesium replaces the
aluminum atoms in the octahedral units.
39.
Bulky
Particles
are formed mostly by mechanical weathering
of rock and minerals.
Cementing
Agents
These are generally carried in solution by
groundwater. They fill the spaces between
particles and form sedimentary rock.
Chalk
Is a sedimentary rock made in part from
biochemically derived calcite, which are
skeletal fragments of microscopic plants and
animals.
40.
41.
59.
Drift
Is a general term usually applied to the
deposits laid down by glaciers.
77.
Gyspum and
Anhydrite
Result from the precipitation of soluble
CaSo4 due to evaporation of ocean water
60.
Dunes
Deposits of windblown sand generally take
the shape of ______________
78.
Hydrogen
Bonding
61.
Effective
Size
The diameter in the particle-size distribution
curve corresponding to 10% finer
A mechanism in which hydrogen atoms in the
water molecules are shared with oxygen
atoms on the surface of the clay.
79.
Erosion
This process causes intrusive rocks to be
uncovered and exposed at the surface.
Hydrometer
Analysis
Mechanical Analysis for particle sizes smaller
than 0.075 mm in diameter.
80.
T/F: Sedimentary and metamorphic rocks do
not weather in the similar manner as Igneous
rocks
Hydrometer
Analysis
Mechanical analysis that is effective for
separating soil fractions down to a size of
about 0.5 microns
81.
Hydrometer
Analysis
Mechanical analysis that is based on the
principle of sedimentation of soil grains in
water. When a soil specimen is dispersed in
water, the particles settle at different
velocities depending on their shape,size and
weight.
82.
Hydrometers
Are designed to give the amount of soil, in
grams, that is still in suspension.
83.
Igneous
Rock
These are formed by the solidification of
molten magma ejected from deep within the
earth's mantle.
84.
Illite
Consists of gibbsite sheet bonded to two
silica sheets-one at the top, and another at
the bottom. Also called as Clay Mica.
85.
Kaolinite
Consists of repeating layers of elemental
silica-gibbsite sheets, they occur as platelest
with a lateral dimension of 1000 to 20000 A
and a thickness of 100 to 1000
62.
63.
False
64.
False
(hardest )
T/F: Quartzite is one of the weakest rocks
65.
False
(negative)
T/F: The clay particles carry a net positive
charge on their surfaces.
66.
False (Top
to Bottom)
T/F: The soil is shaken through a stack of
sieves with openings of decreasing size from
the bottom to top.
67.
False (will
depend)
T/F: The nature of a residual soil deposit will
not generally depend on the parent rock
68.
Fissure
Eruption or
Volcanic
Eruption
A phenomenon which ejects magma out to the
surface.
69.
Flaky
Particles
Have very low sphericity - usually 0.01 or less;
These particles are predominantly clay
minerals.
70.
Gap Graded
A type of soil having a combination of two or
more uniformly graded fractions
86.
Lacustrine
soils
Transported Soil formed by deposition in the
quiet lakes
71.
Glacial Soils
Transported soil formed by transportation and
deposition of glaciers
87.
Landslide
This happens when the downward movement
of soil is sudden and rapid
72.
Glaciofluvial
Deposits
The melted water deposits the outwash
forming outwash plains also called
___________________
88.
Limestone
73.
Gneiss
Is a metamorphic rock derived from highgrade regional metamorphism of igneous
rocks, such as granite, gabbro, and diorite.
Is formed mostly of calcium carbonate
deposited either by organisms or by an
inorganic process. These are clastic in texture
however, non-clastic textures also are found
commonly.
89.
Loess
74.
Gradation
of Particle
Size
An important characteristic of residual soil.
Is an aeolian deposit consisting of silt and
silt-sized particles. The grain-size distribution
of this deposit is rather uniform.
90.
Maiandros
75.
Gravel
Are pieces of rock with occasional particles of
quartz, feldspar, and other minerals.
The term "meander" came from this Greek
word after a river of the same name in Asia,
famous for its winding course.
76.
Ground
Moraine
The till deposited by the glacier between the
moraines is referred to as _________________. They
constitute large areas of central United States
and are called "TILL PLAINS"
91.
Marble
is formed from calcite and dolomite by
recrystallization. The mineral grains in this
rock are larger than those present in the
original rock.
92.
Marine Soils
Transported soil formed by deposition in the
seas
93.
Meander Belt
The valley floor in which a river meanders
is called _____________________
94.
Mechanical
Analysis
Is the determination of the size range of
particles present in a soil, expressed as a
percentage of the total dry weight (or
mass).
95.
96.
97.
Mechanical
Weathering
This type of weathering may be caused by
the expansion and contraction of rocks
from the continuous gain and loss of heat.
Metamorphism
Is the process of changing the
composition and texture of rocks by heat
and pressure. During this process, new
minerals are formed and mineral grains
are sheared to give a foliated-texture to
the rock.
Montmorillonite
Has a similar structure to illite, one
gibbsite sheet sandwiched between two
silica sheets. There is isomorphous
substitution of magnesium and iron for
aluminum in the octahedral sheets
98.
Moraines
The land forms that developed from the
deposits of till
99.
Mud flows
One type of gravity transported soil.
100.
Natural Leeves
The sand and silt particles carried by the
river are deposited along the banks to
form ridges known as _____________________
101.
Needle-shaped
particles
Much less common than the other two
particle types. Example of soils containing
particles of this shape are some coral
deposits and attapulgite clays
102.
Octohedral
Sheet
The combination of the octahedral
aluminum hydroxyl units also called a
gibbsite sheet
103.
Organic Soils
These are usually found in low-lying areas
where the water table is near or above the
ground surface. The presences of a high
water table helps in the growth of aquatic
plants that, when decomposed, form this
type of soil
104.
Ortho-quartzite
When the grains in sandstone are
practically all quartz, the rock is referred
to as ___________________
105.
Outwash
The sand, silt and gravel that are carried
by the melting water from the front of the
glacier are called ______________
106.
Oxbow Lake
This forms when the river abandons a
meander and cuts a shorter path. The
meander filled with water is called
________________
107.
Particlesize
Distribution
Curve
This graph consists of the percent finer as the
ordinate (arithmetic scale) and sieve opening
size as the abscissa (logarithmic scale)
108.
Peats and
Organic
Soil
These are derived from the decomposition or
organic materials.
109.
Phyllite
Is a metamorphic rock, which is derived from
slate with further metamorphism being
subjected to heat greater than 250 to 300
degrees celsius
110.
Plasticity
Is the putty-like property of clays when they
contain a certain amount of water.
111.
Pleistocene
Ice Age
An era when glaciers covered large areas of
the earth. The glaciers advanced and retreated
with time. During their advance, the glaciers
carried large amounts of sand, silt , clay,
gravel and boulder
112.
Plutons
These are intrusive igneous rocks formed when
magma ceases its mobility below the earth's
surface and cools.
113.
Point Bar
Deposits
Deposits derived from Meander-Belt Stream,
they usually consists of sand and silt-sized
particles.
114.
Poorly
Graded Soil
A type of soil grains are the same size.
115.
Quartz
This rock is highly resistant to weathering and
only slightly soluble in water
116.
Quartzite
Is a metamorphic rock formed from quartzrich sandstones. Silica enters into the void
spaces between the quartz and sand grains
and acts as a cementing agent.
117.
Recessional
Moraine
These are ridges of till developed behind the
terminal moraine at varying distances apart.
They are the result of temporary stabilization
of the glacier during the recessional period.
118.
Residual
Soil
These are found in areas where the rate of
weathering is more than the rate of which the
weathered materials are carried away by
transporting agents.
119.
Residual
Soil
These soil deposits generally have a top layer
of clayey or silty clay material, below which
are silty or sandy soil layers. These layers are
generally underlain by a partially weathered
rock and then sound bedrock.
120.
Residual
Soils
The soils formed by the weathered products at
their place of origin.
121.
Rock
Weathering
This is the process wherein the mineral grains
that form the solid phase of a soil aggregate
are produced.
137.
True
T/F: To conduct a sieve analysis, one must first
oven-dry the soil and then break all lumps into
small particles.
122.
Sand
Are particles made of mostly quartz and
feldspar. Other mineral grains may also be
present at times.
138.
True
123.
Schist
Is a type of metamorphic rock derived from
several igneous, sedimentary, and low-grade
metamorphic rocks with a well foliated
texture and visible flakes of platy and
micaceous mineral.
T/F: The rate of weathering is higher in warm
and humid regions compared to cooler and
drier regions and depending on the climatic
conditions.
139.
True
T/F: The grain-size distribution of the sand at
any particular location is surprisingly uniform.
This uniformity can be attributed to the sorting
action of the wind.
140.
True
T/F: In mechanical weathering, large rocks are
broken down into smaller pieces without any
change in the chemical composition.
141.
True
T/F: The Unified Soil Classification System has
now been adopted by the American Society
for Testing and Materials.
142.
Volcanic
Ash
Is a lightweight sand or sandy gravel.
Decomposition of this material results in highly
plastic and compressible clays.
143.
Weathering
This is the process of breaking down rocks by
mechanical and chemical processes into
smaller pieces.
144.
Well
Graded
Soil
A type of soil in which the particle sizes are
distributed over a wide range.
145.
Well
Graded
Soil
A soil has a uniformity coefficient greater than
about 4 for gravels, and 6 for sand, and a
coefficient of gradation between 1 and 3 (for
gravels and sands)
146.
Wind
Is also a major transporting agent leading to
the formation of soil deposits. When large
areas of sand lie exposed, It can blow the sand
away and redeposit it elsewhere.
124.
Sedimentary
Rock
Occurs from the deposits of gravel, sand, silt
and clay formed by weathering that may
become compacted by overburden pressure
and cemented by agents like iron oxide,
calcite, dolomite, and quartz
125.
Sieve
Analysis
Mechanical Analysis for particles sizes larger
than 0.075 mm in diameter.
126.
Sieve
Analysis
Consists of shaking the soil sample through a
set of sieves that have progressively smaller
openings.
127.
Silica
Tetrahedron
Each unit consists of four oxygen atoms
surrounding a silicon atom.
128.
Silt
Are the microscopic soil fractions that
consists of very fine quartz grains and some
flake-shaped particles that are fragments of
micaceous minerals.
129.
Specific
Surface
This is the surface area per unit mass
130.
Stoke's Law
A law expressing the velocity of soil
particles.
131.
Terminal
Moraine
Is a ridge of till that marks the maximum limit
of a glacier's advance.
132.
Till
Unstratified deposits laid down by melting
glaciers are referred to as _______________________
133.
Tropics
This are where residual soil are most
commonly found.
134.
True
T/F: The deltas formed in humid regions
usually have finer grained soil deposits
compared to those in arid regions.
135.
True
T/F: Under extreme heat and pressure,
metamorphic rocks may melt to form magma,
and the rock cycle is repeated.
136.
True
T/F: Sedimentary Rock may undergo
weathering to form sediments or may be
subjected to the process of metamorphism to
form metamorphic rock.
Soil Mechanics - Exam 1
Study online at quizlet.com/_g7tyk
1.
0<LI<1
Plastic
19.
esker
uniform
2.
1m^3=?L
1000L
20.
Fluvial Soil
3.
Asthenosphere
low mantle, hot, weak,
ductile
deposited by streams and
fresh water
21.
Geosynthetics
man made plastic sheets
(hydraulic barriers)
22.
Gravemetric Water
Content=
Water
Content=W(water)/W(solids)
23.
How old is the Earth?
4.6 billion years
24.
Hydraulic Conductivity what happens to it wet and
dry of optimum?
decreases wet of optimum,
stronger on dry of optimum
25.
Igneous Rock
solidified from molten rock
26.
Is clay strong or weak dry
of optimum?
strong
27.
Is surface force more
important for coarse grain
or fine grain material?
fine
28.
LI<0
semi-solid (strong)
29.
LI>1
Liquid (low strength)
30.
Lift
soil layer to be compacted
31.
liquidity index=
LI(or IL)=(w-PL)/(LL-PL)
32.
liquid limit
water content for liquid
behavior
33.
Lithosphere
rocky upper mantle and crust,
moves as solid plate
34.
loess
wind blown salt
(homogeneous size)
35.
Mineral
naturally formed, solid,
forged inorganically,
specified chemical
composition
36.
Non-clay physical
characteristics
particle size, particle
distribution, particle shape,
surface texture
37.
Plasticity Index
PI=LL-PL
38.
plastic limit
water content for plastic
behavior
39.
Porosity=
Porosity=Vv/Vt=e/(1+e)
40.
Regolith
loose layer of debris from
weathering
41.
Relationship between
surface area and interaction
more surface area more
interaction
42.
Relationship between
surface area and
interparticle force
more surface area more
interparticle force
4.
Boring and Drilling
destructive method of
sub surface exploration
visual ID of soil type with
sample collection
5.
Cc
(D30)^2/D10*D60
6.
Compaction
densification of soil and
rocks by applying
mechanical engergy
7.
Compaction
Deliver specific amount
of mechanical energy to
a soil specimen
8.
Consolidation
water forced out of pore
spaces
9.
Continuous flight boring
destructive method of
sub surface exploration
-solid stem (have to keep
removing it from hole,
time consuming)
-hollow stem (auger acts
as casing to equalize
pressure)
-hand auger (cheap,
limited depth)
-water borings
(pressurized water down
drill shaft)
10.
Cu
D60/D10
11.
Cycle for rocks
rocks formed --> uplift -->
weathering
12.
Diff between magma and lava?
magma is underground
(intrusive), lava is above
(extrusive)
13.
differential settlement
one side settles, not the
other
14.
Does coarse grain or fine grain
have higher surface area to
weight ratio?
Fine grained has higher
surface area to weight
ratio
does well graded soil or poorly
graded soil have higher hydraulic
conductivity?
poorly graded has higher
hydraulic conductivity
Dry Unit Weight=
Dry Unit
Weight=W(solids)/V(total)
15.
16.
17.
Effective stress
stress felt by soil skeleton
18.
Eolian soil
transported by wind
43.
relationship btwn
Vs, Ws, Gs, unit
weight of water
Vs=Ws/(Gs*unit_weight_of_water)
62.
What are the differences
between sand and clay?
(size, shape, strength
comes from __?)
Sand: larger/coarse grained,
rounder, strength from frictional
forces between particles
Clay: small/fine grained, flat,
strength from water interaction
44.
Residual soil
rate of soil formation is faster than
transportation/erosion
45.
Retaining
Structures
Hold soil at steeper slope than the soil
can stand
63.
Dry density, water content, soil
type, compactive effort
naturally formed aggregate(collection)
of minerals
What are the four
variables that compaction
is a function of?
46.
Rock
64.
saltation
large sand picked up and moved a
short distance
What are the three main
rock groups?
igneous, sedimentary,
metamorphic
47.
65.
Saturated Unit
Weight=
W(solids)+W(water)/V(total)
What are the three types
of clay structures
kaoline-strong bonding
Illite-stable, K bond
Sretile/Montmorillonite-weak
bond
48.
66.
What are three methods
of retrieving a soil sample
shelby tube
split spoon
block
67.
What happens to
permiability wet and dry
of optimum when
increasing water content?
permiability decreases dry of
opt, increases wet of opt
68.
what is a typical specific
gravity?
2.6-2.8
69.
What is the difference
between standard proctor
test and modified proctor
test?
Standard has a lower max dry
unit weight and higher optimum
water content
70.
What orientation is clay
strongest?
clay has high perpendicular
strength, not parallel
71.
What rocks make up the
crust, what rocks make up
the surface?
crust = 95% igneous and
metamorphic
surface = 75% sedimentary
72.
What three things does
compacting clay do?
pushes particles closer
together, decreases potential
volume change, and decreases
hydraulic conductivity
73.
Which are minerals? ice,
water, coal
ice=mineral
water=not mineral
coal=not mineral
where V(water)=V(voids)
49.
Saturation=
Saturation=Vw/Vv
50.
settlement
volume is changing
51.
size for coarse and
fine gravel
coarse = 19-75mm
fine=4.75-19mm
52.
Sizes for coarse
and fine grain?
coarse >.075mm
fine <.075mm
53.
Soil
Weathering rocks and minerals
54.
Soil Mechanics
Application of static, mechanics of
materials, and fluid mechanics to
describe the behavior of soils
55.
Stokes Law
D=sqrt(18mz/(Gs-1)unitweightwatert))
D-particle size diameter
Gs=specific gravity of soilds
m=viscosity fluid
z=depth from hydrometer
***stokes law doesn't apply to clay
56.
Typical Gs
2.7
57.
Unit Weight=
Unit Weight=W/V
58.
Void Ratio=
Void Ratio=V(void)/V(solid)
59.
Volumetric Water
Content=
Volumetric Water
Content=V(water)/V(total)
60.
Water Unit Weight=
Water Unit
Weight=9.81=W(water)/V(water)
61.
What are the 4
phases of field
investigation
1. collect info
2. familiarize with site
3. detailed site investigation
4. write report
Soil Mechanics: Exam 1, Soil Mechanics Exam 2
Study online at quizlet.com/_5t5p0o
1.
2 types of
compression
1. elastic, 2. consolidation
17.
Compression in
the soil
due to applied loads (top surface of the
soil moves downward)
2.
#200 sieve
200 opening per 1 linear inch sieve
18.
3.
The
allowable
bearing
capacity of
soil
maximum unit pressure that foundation can
withstand vertically or laterally on soil mass
Concern on the
differential
settlement
Create distress to the building, the
excessive differential settlement
damage hugely due to the moments
and the bending stresses. The concrete
= crack, the reinforcement of the
building exposed.
4.
As
construction
materials
Bearing pressure = force/area
If the soil cannot withstand the bearing
pressure, the building will sink. (solution: drill
down to bed rock for stronger supports)
19.
Consolidation
Slow (permeability), driving out water,
under the static loads
20.
Consolidation
(primary)
5.
ASTM
Unified Soil
Classification
System
Gravel (6.4-76.2mm), sands (0.05-6.4mm), silts
(0.002-0.05mm) and clays (<0.002mm) based
on physical composition and characteristics
volume changes due to expulsion of
water from voids (Vv changes with VT)
Initially, the loads on the surface are
resisted by "Excess" pore water
pressure), then it slowly transferred to
the soil skeleton (effective stress)
6.
At the
groundwater
zone (below
water table)
S = 1, Vv = Vw, Hydrostatic pressure exists,
resist both effective stress and hydrostatic
pressure
21.
Construction of
the foundation
increase in net stress (depends on load
per unit area, depth at estimation of
stress made, other factors)
22.
D60,D30,D10
At the
unsaturated
zone (above
water table)
S < 1, No hydrostatic pressure, resist only
effective stress
Diameter associated with 60%,30%, and
10% respectively
23.
Density
determine the bearing capacity of
granular soils
24.
8.
The boiling
typically occurs on the sand, (soil at depth
can't support load (soil above + surcharge),
typically soil with upward waterflow)
Depth and the
stress
As depth deepens, the weight above
increases (stress increases). The
resistance behavior at the top and the
bottom is different
9.
Classification
of Coarse
grained soil
sieve analysis: separate particle by sizes Distribution: plot % finer (% passing) vs grain
size (log size)
25.
10.
Clay soils
is unstable as it shrinks and swells with
changes in moisture content.
The differences
between the
primary and
secondary
consolidation
11.
Coarse
grained soil
gravel and sand = relatively large particles
(visible to naked eye)
Primary consolidation = consolidation
initially occurs (due to applied weight
on the surface)
Secondary consolidation =
consolidation happens after the primary
consolidation that happens slow pace
due to creep, viscous behavior.
Coarse
Grained soils
low percentage of void spaces, more stable
as foundation materials than silt or clay, more
permeable and drain better than fine grained
soil, less susceptible to frost action
26.
12.
The discharge
velocity and
seepage velocity
13.
Cohesion
chemical reaction between fine and water
14.
Cohesive
soils
clay - retain strength when unconfined
discharge velocity is the rate of liquid
flow at certain area while the seepage
velocity is the velocity of the ground
water
(seepage velocity = different for each
path - particle do not flow in straight
line)
27.
15.
Compaction
quick, driving out air and water, under the
dynamic loads
16.
Compaction
(rolling,
tamping, or
soaking)
to achieve optimum moisture content, increase
the density of soil bed
Distribution of
Stress along a
given cross
section of soil
profile (Effective
stress concept )
Some fraction of the Normal stress at a
given depth in a soil mass is carried by
water in void space, other carried by
the soil skeleton at points of contact of
the soil particles
7.
28.
Distribution of
Stress along a
given cross
section of soil
profile helps to
analyze
compressibility of soils, bearing capacity
of foundation, stability of embankments,
lateral pressure on earth-retaining
structures
37.
The field
permeability
test for the
hydraulic
gradient is
conducted
1. lab setting not same as actual setting
(soil, density, structure, saturation)
2. the boundary of the soil at the lab=
different than the soil at the site
3. size of sample different
4. the existence of nonlinear Darcy's law
29.
Distribution or
gradation of
soil grains
determine permeability and strength of the
soil
38.
Fine Grained
soil
silt and clay = smaller particles
39.
Flow direction
Water moves from high to low total head
30.
Effective
Stress
Rest of total stress carried by the soil
grains at their points of contact. The sum of
vertical components of the forces
developed at the points of contact of the
solid particles per unit cross-sectional area
of the soil mass.
40.
Flow line
Lines on the Flow nets representation that
represents the movement of water particles
in the soil
41.
Flow net
representation
related to
Laplace's
equation of
continuity
Flow nets are the visual representation of
the Laplace Equation (Darcy law). The
Laplace equation in an isotropic soil = two
orthogonal families of curves (flow lines
and equipotential line). Determine the pore
water pressure at different location, the
uplift force....
42.
The
foundation
sand = stronger than the clay, the water
leaves quickly through the sand (high
permeability) (better drainage characteristic)
43.
foundation
system
groundwater should be removed to avoid
reducing the bearing capacity of the soil
and to minimize the possibility of water
leaking into a basement
44.
Friction
force between 2 surfaces = normal force *
coefficient of static friction
45.
Friction in soils
1. grain to grain contact, 2. assume grains do
not crust or yield, 3. grains do slide passed
each other, 4. friction strength = shear
strength = Normal stress coefficient of
static friction = Normal stress tan(soil
property)
46.
Granular soils
(gravel, sand,
or some silts)
require confining force for shear resistance.
Have a shallow angle of repose
47.
The heaving
typically occurs on the clay, (water under
pressure, pushes soil upward, typically clay
excavation)
48.
High
Permeable soil
The highway for the drainage (remove water
on the roads for the safety)
49.
The integrity
of building
structure
depends on stability and strength under
loading of the soil underlying the
foundation
31.
effective stress
is
2. the stress that is resisted by the soil
skeleton
1. the stress
resisted by the
water in the
voids and the
soil skeleton
2. the stress
that is resisted
by the soil
skeleton
3. the stress
resisted by the
water in the
voids
32.
Effect of static
water
buoyancy force act on soil column
displacing water
33.
Effects of void
ratio to
permeability
Void ratio is the ratio of the voids' volume
to solid's volume. Higher the voids'
volume, more space for fluids to move
through
34.
Elastic
compression
occurs instantly, elastic deformation of the
soil solids, no change in moisture content
35.
Empirical
Equation
Equation created from the experience or
observation, not the theories
36.
Factor
influencing to
water flow
permeability, porosity/void ratio, gradation
(poor - better flow), saturation (high
saturation - easier), grain size(higher - more
voids - better flow), clays ( slower than
others due to chemical, fine, attraction to
water molecules)
50.
Law of the Flow net
1. smooth equipotential line
2. flow line and equipotential line =
not go through the impermeable
materials
3. flow line = perpendicular to
equipotential line and the soil
surface
4. Elements are not square
51.
Loss of head
Occurs as water flows through soils
52.
Low permeable soil
For the earth dam, storing water
without any leaks
53.
Moisture content and
void volume is
important
to determine the unit weight
54.
Normally
consolidated soil
current stress = max past stress
(reconsolidation stress)
55.
the number of blows
required by a hammer
to advance a
standard soil sampler
measures the density of granular
soils and the consistency of some
clays at the bottom of a borehole
(the Standard Penetration Test)
56.
over consolidated soil
current stress < the past max stress
(reconsolidation stress)
57.
Pore water pressure
1. is the hydrostatic pressure
1. is the hydrostatic
pressure
2. changes as the
height of the soil
column increases
3. is different in
vertical and
horizontal directions
58.
Pore Water Pressure
(hydrostatic pressure)
The portion of total stress carried
by water in continuous void spaces
(equal intensity in all direction)
59.
Reason why the
constant head
permeability test is
not used for clays
constant head permeability test
(sands)
Falling head permeability test
(clays)
It is because it takes a lot of time to
collect water coming out of the clay
due to low permeability - not
practical
60.
61.
Secondary
consolidation
plastic readjustment of soil fabric
Seepage and
Effective stress
The downward seepage increases
the effective stress due to change
increase in pore water pressure
62.
Seepage and porewater
pressure
The downward seepage
decreases the porewater pressure
due to change in water height
63.
Seepage and total
stress
The downward seepage
decreases the total stress since
the effects on the porewater
pressure and the effective stress
cancel out each other
64.
Select the incorrect
statement.
2. Cohesive soils, such as silt,
maintain their strength when
unconfined.
1. Clay soils are unstable
because they shrink and
swell considerably with
changes in moisture
content.
2. Cohesive soils, such as
silt, maintain their
strength when
unconfined.
3. Coarse-grained soils
are more stable as a
foundation material than
silt or clay.
65.
Settlement of saturated
sand vs saturated clay
Sand - water flow out really
quickly
Clay - water flow out slowly
Rate of settlement quicker for the
sand
66.
shearing strength of a
soil
measure of its ability to resist
displacement when an external
force is applied, due largely to
the combined effects of cohesion
and internal friction
67.
Similarities of the
boiling and the heaving
both is the phenomenon related
to the water under the soil
68.
Sloped sites &
excavation of a flat site
unconfined soil displace laterally
69.
Soil anisotropy
accounted for using
flow nets
The horizontal scale must
sqrt(kz/kx) times the verticle
scale. The rate of seepage per
unit length needs to be
calculated with a modification.
70.
Soil Classification
methods vary depending on grain
size, huge difference in physical
properties between soil types,
classification helps defining
behaviors
71.
soil classification
systems
AASHTO (roads), USCS - Unified Soil
Classification System (structure)
72.
Soil collected
through test pits
or test borings
can be used to
understand:
4. All answers provided are correct
1. Extent of soil
consolidation
under loading
2. Permeability
of soil
3. Water content
of soil
4. All answers
provided are
correct
73.
Soil is a threephase system
consisting of
what phases?
soil profile
the diagram of vertical section of soil
from the ground surface to the
underlying material
75.
Soil Strength
= f = cohesion friction
76.
soil type
cohesive (clay - resist some tension) vs
noncohesive (sand and gravel)
77.
The soil
underlying a
building site
consist of superimposed layer (mix of
soil types due to weathering or
deposition)
78.
solids
different size, shape, angularity
79.
A subsurface
investigation
includes
the analysis and testing of soil disclosed
by excavation of test pit up to 3m deep
or deeper test boring
A subsurface
investigation is
conducted to
understand the structure of soil, its shear
resistance and compressive strength, its
water content and permeability, and the
expected extent and rate of consolidation
under loading
Suitability of soil
as a foundation
materials
the value of potential heads along the line
are same
83.
Total stress
resisted by 1. soil skeleton (due to contact
forces between soil particles (effective
stress) and 2. pore water pressure (unit
weight of water * height of water column)
84.
total stress
The total vertical stress acting at a point
below the ground surface is due to the
weight of everything lying above
85.
Total stress at
a point is
1. resisted by the soil skeleton and the
water in the voids
1. resisted by
the soil
skeleton and
the water in
the voids
2. resisted by
the water in
the voids
3. resisted by
the soil
skeleton
86.
74.
81.
Th
Equipotential
line
3. water, solids, air
1. clay, silt, sand
2. solids, voids,
water
3. water, solids,
air
80.
82.
the stratification, composition, and
density of the soil bed & variations in
particle size, and the presence or
absence of ground water
Total stress at
a point is due
to
1. the weight of everything acting above
that point
1. the weight of
everything
acting above
that point
2. the weight
of the water in
the voids
above that
point
3. the weight
of the soil
solids above
that point
87.
Total Stress
(vertical stress)
stress imposed below the ground due to
everything (including the soil above it)
above the point of interest = sum of unit
weight * depth +surface loads
88.
two broad
classes of soils
coarse grained soils and fine grained soil
89.
USCS
classification based on 1. size of soil grain, 2.
distribution or gradation of soil grains (well
graded: well distribution of different soil grain
size), 3. organic components (organic: behave
weird - remove for the stable supports), 4.
behavior of fine particles (sticky or not)
90.
USCS fine
classification
1. water content (moisture content), 2.
Atterberg limits
91.
USCS fine
classification
- Atterberg
limits
1. Liquid Limit: water content that separates
liquid and plastic status, 2. plastic limit: water
content that separates plastic and semi solid
USCS fine
classification
- plastic
index
differences between liquid limit and plastic
limit
USCS fine
classification
- Water
content
94.
99.
Void ratio is:
1. ratio of the volume of the voids
to the total volume
2. ratio of the volume of the voids
to the volume of the solids
3. ratio of the volume of water to
the volume of the voids
2. ratio of the volume
of the voids to the
volume of the solids
100.
Voids
consists of water
(bottom) and air (top)
101.
Void Spaces
Continuous and
occupied by water, air,
or both
102.
Volume of Soil
liquid (High water content - flow), plastic
(medium water content - sticks), solid or semi
solid (low water content - crumbles)
Solid particle
distributed randomly
with void spaces in
between
103.
The water table
level beneath which
the soil is saturated
with groundwater
USCS
gradation
classification
well graded, poor graded, gap graded
104.
Which of the following statements
is incorrect?
95.
USCS
gradationGap graded
Some sizes are not existed in the soil
3. In general, bearing
capacity decreases
with increased soil
density.
96.
USCS
gradation Poorly
graded
(uniformly
graded)
soil in narrow bands of sizes, lots of similar
sizes
97.
USCS
gradationwell graded
wide range of sizes, can pack closely
together
USCS soil
classification
based on
grain size
Boulder (>12''), Cobbles(>3"), Gravel(>#4),
Sand(>#200), Fine (clay, silt)
92.
93.
98.
1. Clay soils can be unstable
because they may shrink and
swell with changes in moisture
content.
2. Clays tend to be impervious to
fluids.
3. In general, bearing capacity
decreases with increased soil
density.
4. The water table is the level
beneath which the soil is saturated
with groundwater.
105.
Which soil classification would be
expected to have the highest
bearing capacity?
1. Silt
2. Sand w/ fines
3. Clean gravel
4. Clay
3. Clean gravel
Soil Mechanics Definition of Terms
Study online at quizlet.com/_8hj5hn
1.
Active earth
pressure
coefficient
(Ka)
is the ratio between the lateral and vertical
principal effective stresses at the limiting
stress state when an earth-retaining structure
moves away (by a small amount) from the
backfill (retained soil).
2.
Allowable
bearing
capacity or
safe bearing
capacity (qa)
is the working pressure that would ensure a
margin of safety against collapse of the
structure from shear failure. The allowable
bearing capacity is usually a fraction of the
ultimate net bearing capacity.
Anisotropic
means the material properties are different in
different directions, and also the loadings are
different in different directions.
3.
Apparent
cohesion (C)
is the apparent shear strength at zero normal
effective stress.
Average
particle
diameter
(D50)
is the average particle diameter of the soil.
6.
Backfill
is the soil retained by the wall.
7.
Barrette pile
is a drilled shaft created by making an
excavation with a grab rather than an auger. It
have square or rectangular cross sections.
4.
5.
8.
Bulk unit
weight (γ)
is the weight density, that is, the weight of a
soil per unit volume.
9.
Cementation
is a measure of the shear strength of a soil
from forces that cement the particles.
10.
Coefficient
of curvature
(CC)
is a measure of the shape of the particle
distribution curve (other terms used are the
coefficient of gradation and the coefficient of
concavity).
11.
Cohesion (co)
is a measure of the intermolecular forces.
12.
Compaction
is the densification of soils by the expulsion
of air.
13.
Compression
index
is the slope of the normal consolidation line
in a plot of void ratio versus the natural
logarithm of mean effective stress.
14.
Compression
index, Cc
is the slope of the normal consolidation line
in a plot of the logarithm of vertical effective
stress versus void ratio.
15.
16.
17.
Cone tip
resistance
(qc)
is the average resistance (average vertical
stress) of the cone in a CPT.
Consolidation
is the time-dependent settlement of soils
resulting from the expulsion of water from
thesoil pores.
CPT
is the cone penetrometer test
18.
Critical state
is a stress state reached in a soil when
continuous shearing occurs at constant shear
stress to normal effective stress ratio and
constant volume.
19.
Critical state
line (CSL)
is a line that represents the failure state of
soils.
20.
Degree of
compaction
(DC)
also called relative compaction, is the ratio
of the measured dry unit weight achieved to
the desired dry unit weight.
21.
Degree of
saturation (S)
is the ratio of the volume of water to the
volume of voids.
22.
Density index
(Id)
is a similar measure (not identical) to relative
density.
23.
Deviatoric
stress, q
is the shear or distortional stress or stress
difference on a body.
24.
Dilation
is a measure of the change in volume of a
soil when the soil is distorted by shearing
25.
Displacement
pile
is a pile that displaces a large volume of
soil. Driven piles with solid sections are
displacement piles. Closed-ended pipe piles
are displacement piles.
26.
Drainage
path, Hdr
is the longest vertical path that a water
particle will take to reach the drainage
surface.
27.
Drilled shaft
or bored pile
is a concrete pile cast in a hole created by a
spiral auger. These piles are generally
cylindrical.
28.
Dry unit
weight (γd)
is the weight of a dry soil per unit volume.
29.
Effective
friction angle
is a measure of the shear strength of soils
due to friction.
30.
Effective
particle size
(D10)
is the average particle diameter of the soil at
the 10th percentile; that is, 10% of the
particles are smaller than this size (diameter).
31.
Effective
stress
is the stress carried by the soil particles.
32.
Effective unit
weight (γ′)
is the weight of a saturated soil submerged in
water per unit volume.
33.
Elastic
materials
are materials that return to their original
configuration on unloading and obey Hooke's
law.
34.
Embedment
depth (Df)
is the depth below the ground surface where
the base of the foundation rests.
35.
End bearing
or point
bearing pile
is one that transfers almost all the structural
load to the soil at the bottom end of the pile.
End bearing
or point
resistance or
tip
resistance
(Qb)
is the resistance generated at the base or tip
of a pile.
End bearing
stress or
point
resistance
stress or tip
resistance
stress (fb)
is the stress at the base or tip of a pile.
38.
Equipotential
line
is a line representing constant head.
39.
Excess
porewater
pressure, Du
is the porewater pressure in excess of the
current equilibrium porewater pressure.
40.
Factor of
safety or
safety factor
(FS)
s the ratio of the ultimate net bearing
capacity to the allowable net bearing
capacity or to the applied maximum net
vertical stress. In geotechnical engineering, a
factor of safety between 2 and 5 is used to
calculate the allowable bearing capacity.
Flexible
retaining
wall or sheet
pile wall
is a long, slender wall relying on passive
resistance and anchors or props for its
stability.
42.
Floating pile
is a friction pile in which the end bearing
resistance is neglected.
43.
Flow line
is the flow path of a particle of water.
44.
Flownet
is a graphical representation of a flow field.
45.
Footing
is a foundation consisting of a small slab for
transmitting the structural load to the
underlying soil.
36.
37.
41.
46.
Foundation
is a structure that transmits loads to the
underlying soils.
47.
Friction pile
is one that transfers almost all the structural
load to the soil by skin friction along a
substantial length of the pile.
48.
Gravity
retaining
wall
is a massive concrete wall relying on its mass
to resist the lateral forces from the retained
soil mass.
49.
Groundwater
is water under gravity that fills the soil pores.
50.
Groundwater
is water under gravity that fi lls the soil pores.
51.
Head (H)
is the mechanical energy per unit weight.
52.
Head (H)
is the mechanical energy per unit weight
53.
Hydraulic
conductivity,
sometimes called the coeffi cient of
permeability, (k) is a proportionality
constant used to determine the flow
velocity of water through soils.
54.
Hydraulic
conductivity
sometimes called the coefficient of
permeability, (k) is a proportionality
constant used to determine the flow
velocity of water through soils.
55.
Isotropic
means the material properties are the
same in all directions, and also the
loadings are the same in all directions.
56.
Isotropic
means the same material properties in all
directions and also the same loading in
all directions.
57.
Liquidity index
(LI)
is a measure of soil strength using the
Atterberg limits (liquid and plastic limits
based on test data).
58.
Liquid limit (LL)
is the water content at which a soil
changes from a plastic state to a liquid
state.
59.
Maximum dry unit
weight (γd(max))
is the maximum unit weight that a soil
can attain using a specified means of
compaction.
60.
Mean stress, p
is the average stress on a body or the
average of the orthogonal stresses in
three dimensions.
61.
Mechanical
stabilized earth
is a gravity-type retaining wall in which
the soil is reinforced by thin reinforcing
elements (steel, fabric, fi bers, etc.)
62.
Micropiles
are small-diameter piles (50 mm to 340
mm) installed as pipe piles. They are
also called minipiles, pin piles, needle
piles, and root piles.
63.
Minerals
are chemical elements that constitute
rocks.
64.
N
is the number of blows for the last 12 in
penetration of an SPT sampler.
65.
Nondisplacement
pile
is a pile that displaces only a small
volume of soil (< 10%) relative to its
external volume.
66.
Normally
consolidated soil
is one that has never experienced
vertical effective stresses greater than its
current vertical effective stress.
67.
Optimum water
content (wopt )
is the water content required to allow a
soil to attain its maximum dry unit weight
following a specified means of
compaction.
68.
Overconsolidated
soil
is one that has experienced vertical
effective stresses greater than its
existing vertical effective stress.
69.
Overconsolidation
ratio, OCR
is the ratio by which the current vertical
effective stress in the soil was exceeded
in the past.
Passive earth
pressure
coefficient (Kp)
is the ratio between the lateral and
vertical principal effective stresses at
the limiting stress state when an earthretaining structure is forced against a
soil mass.
71.
Past maximum
vertical effective
stress
is the maximum vertical effective stress
that a soil was subjected to in the past.
72.
Pile
is a slender, structural member
consisting of steel, concrete, timber,
plastic, or composites.
70.
85.
Secondary
compression
is the change in volume of a fi ne-grained
soil caused by the adjustment of the soil
fabric (internal structure) after primary
consolidation has been completed.
86.
Seepage stress
is the stress (similar to frictional stress in
pipes) imposed on a soil as water flows
through it.
87.
Serviceability
limit state
defines a limiting deformation or
settlement of a foundation, which, if
exceeded, will impair the function of the
structure that it supports.
88.
Shallow
foundation
is one in which the ratio of the
embedment depth to the minimum plan
dimension, which is usually the width (B),
is Df/B is less than or equal to 2.5.
89.
Shear strength
of a soil
is the maximum internal resistance to
applied shearing forces.
73.
Plasticity index
(PI)
is the range of water content for which a
soil will behave as a plastic material
(deformation without cracking).
90.
Shrinkage index
(SI)
is the range of water content for which a
soil will behave as a semisolid
(deformation with cracking).
74.
Plastic limit (PL)
is the water content at which a soil
changes from a semisolid to a plastic
state.
91.
Shrinkage limit
(SL)
is the water content at which a soil
changes from a solid to a semisolid state
without further change in volume.
75.
Plastic materials
_____________________ do not return to their
original configuration on unloading.
92.
is the frictional force generated on the
shaft of a pile.
76.
Porewater
pressure, u
is the pressure of the water held in the
soil pores.
Skin friction or
shaft friction or
side shear (Qf)
93.
77.
Porewater
pressure (u)
is the average pressure of water within
the soil pores.
is the frictional or adhesive stress on the
shaft of a pile.
78.
Porewater
pressure (u)
is the pressure of water within the soil
pores.
Skin friction
stress or shaft
friction stress or
adhesive stress
(fs)
Porosity (n)
is the ratio of the volume of voids to the
total volume of soil.
94.
79.
Sleeve
resistance (fs)
is the average resistance of the sleeve or
shaft of the CPT.
Preconsolidation
ratio
is the ratio by which the current mean
effective stress in the soil was exceeded
in the past
95.
Soils
80.
are materials that are derived from the
weathering of rocks.
96.
is the change in volume of a finegrained soil caused by the expulsion of
water from the voids and the transfer of
stress from the excess porewater
pressure to the soil particles.
is the ratio of the intact strength to the
disturbed strength.
81.
Primary
consolidation
Soil sensitivity
(St )
97.
Soil tension
is a measure of the apparent shear
strength of a soil from soil suction
(negative porewater pressures or
capillary stresses).
82.
Relative density
(Dr)
is an index that quantifies the degree of
packing between the loosest and
densest state of coarse-grained soils.
98.
SPT
is the standard penetration test.
99.
Static
liquefaction
Rocks
are the aggregation of minerals into a
hard mass.
is the behavior of a soil as a viscous fluid
when seepage reduces the soil's effective
stress to zero.
100.
Static
liquefaction
is the behavior of a soil as a viscous fluid
when seepage reduces the effective
stress to zero.
83.
84.
Saturated unit
weight (γsat)
is the weight of a saturated soil per unit
volume.
Steel Hpiles and
openended pipe
piles are
__________
nondisplacement piles.
102.
Strain or
intensity of
deformation
is the ratio of the change in a dimension to the
original dimension or the ratio of change in
length to the original length.
103.
Stress,
or intensity of loading, is the load per unit
area. The fundamental definition of stress is
the ratio of the force delta P acting on a plane
delta S to the area of the plane delta S when
delta S tends to zero; Delta denotes a small
quantity.
101.
113.
Ultimate net bearing
capacity (qu)
is the maximum pressure that the soil
can support above its current
overburden pressure.
114.
Undrained shear
strength
is the shear strength of a soil when
sheared at constant volume.
115.
Uniformity
coefficient (Cu)
is a numerical measure of uniformity
(majority of grains are approximately
the same size).
116.
Unit weight ratio or
density ratio (Rd)
is the ratio of the unit weight of the
soil to that of water.
117.
Unloading/reloading
index, or
recompression index
(k)
is the average slope of the
unloading/reloading curves in a plot
of void ratio versus the natural
logarithm of mean effective stress.
104.
Stress path
is a graphical representation of the locus of
stresses on a body.
118.
Void ratio (e)
is the ratio of the volume of void
spaces to the volume of solids.
105.
Stress
(strain)
state at a point is a set of stress (strain)
vectors corresponding to all planes passing
through that point. Mohr's circle is used to
graphically represent stress (strain) state for
two-dimensional bodies.
119.
Water content (w)
is the ratio of the weight of water to
the weight of solids.
106.
Swell factor
(SF)
is the ratio of the volume of excavated
material to the volume of in situ material
(sometimes called borrow pit material or
bank material).
107.
Total stress
(s)
is the stress carried by the soil particles and
the liquids and gases in the voids.
108.
Ultimate
bearing
capacity
is the maximum pressure that the soil can
support.
109.
Ultimate
gross
bearing
capacity
(qult )
is the sum of the ultimate net bearing capacity
and the overburden pressure above the
footing base.
110.
Ultimate
group load
capacity
is the maximum load that a group of piles can
sustain before soil failure occurs.
111.
Ultimate
limit state
defines a limiting stress or force that should
not be exceeded by any conceivable or
anticipated loading during the design life of a
foundation or any geotechnical system.
112.
Ultimate
load
capacity
(Qult )
is the maximum load that a pile can sustain
before soil failure occurs.
Soil Mechanics: Exam 1
Study online at quizlet.com/_5aiivd
1.
#200 sieve
200 opening per 1 linear inch sieve
2.
The
allowable
bearing
capacity of
soil
maximum unit pressure that foundation can
withstand vertically or laterally on soil mass
3.
As
construction
materials
Bearing pressure = force/area
If the soil cannot withstand the bearing
pressure, the building will sink. (solution: drill
down to bed rock for stronger supports)
4.
ASTM
Unified Soil
Classification
System
Gravel (6.4-76.2mm), sands (0.05-6.4mm), silts
(0.002-0.05mm) and clays (<0.002mm) based
on physical composition and characteristics
5.
At the
groundwater
zone (below
water table)
S = 1, Vv = Vw, Hydrostatic pressure exists,
resist both effective stress and hydrostatic
pressure
6.
At the
unsaturated
zone (above
water table)
S < 1, No hydrostatic pressure, resist only
effective stress
7.
Classification
of Coarse
grained soil
sieve analysis: separate particle by sizes Distribution: plot % finer (% passing) vs grain
size (log size)
8.
Clay soils
is unstable as it shrinks and swells with
changes in moisture content.
9.
Coarse
grained soil
gravel and sand = relatively large particles
(visible to naked eye)
10.
Coarse
Grained soils
low percentage of void spaces, more stable
as foundation materials than silt or clay, more
permeable and drain better than fine grained
soil, less susceptible to frost action
11.
Cohesion
chemical reaction between fine and water
12.
Cohesive
soils
clay - retain strength when unconfined
13.
Compaction
(rolling,
tamping, or
soaking)
to achieve optimum moisture content, increase
the density of soil bed
Construction
of the
foundation
increase in net stress (depends on load per
unit area, depth at estimation of stress made,
other factors)
15.
D60,D30,D10
Diameter associated with 60%,30%, and 10%
respectively
16.
Density
determine the bearing capacity of granular
soils
14.
17.
Depth and the
stress
As depth deepens, the weight above
increases (stress increases). The resistance
behavior at the top and the bottom is
different
18.
Distribution of
Stress along a
given cross
section of soil
profile (Effective
stress concept )
Some fraction of the Normal stress at a
given depth in a soil mass is carried by
water in void space, other carried by the
soil skeleton at points of contact of the
soil particles
19.
Distribution of
Stress along a
given cross
section of soil
profile helps to
analyze
compressibility of soils, bearing capacity
of foundation, stability of embankments,
lateral pressure on earth-retaining
structures
20.
Distribution or
gradation of soil
grains
determine permeability and strength of
the soil
21.
Effective Stress
Rest of total stress carried by the soil
grains at their points of contact. The sum
of vertical components of the forces
developed at the points of contact of the
solid particles per unit cross-sectional
area of the soil mass.
22.
effective stress
is
2. the stress that is resisted by the soil
skeleton
1. the stress
resisted by the
water in the
voids and the
soil skeleton
2. the stress that
is resisted by the
soil skeleton
3. the stress
resisted by the
water in the
voids
23.
Effect of static
water
buoyancy force act on soil column
displacing water
24.
Fine Grained soil
silt and clay = smaller particles
25.
foundation
system
groundwater should be removed to avoid
reducing the bearing capacity of the soil
and to minimize the possibility of water
leaking into a basement
26.
Friction
force between 2 surfaces = normal force *
coefficient of static friction
27.
Friction in soils
1. grain to grain contact, 2. assume grains
do not crust or yield, 3. grains do slide
passed each other, 4. friction strength =
shear strength = Normal stress coefficient
of static friction = Normal stress tan(soil
property)
28.
Granular soils
(gravel, sand, or
some silts)
require confining force for shear resistance.
Have a shallow angle of repose
29.
The integrity of
building
structure
depends on stability and strength under
loading of the soil underlying the
foundation
30.
Moisture
content and
void volume is
important
to determine the unit weight
31.
the number of
blows required
by a hammer to
advance a
standard soil
sampler
measures the density of granular soils and
the consistency of some clays at the
bottom of a borehole (the Standard
Penetration Test)
Pore water
pressure
1. is the hydrostatic pressure
32.
1. is the
hydrostatic
pressure
2. changes as
the height of
the soil column
increases
3. is different in
vertical and
horizontal
directions
33.
Pore Water
Pressure
(hydrostatic
pressure)
34.
Select the incorrect
statement.
2. Cohesive soils, such as silt,
maintain their strength when
unconfined.
1. Clay soils are unstable
because they shrink and
swell considerably with
changes in moisture
content.
2. Cohesive soils, such as
silt, maintain their
strength when
unconfined.
3. Coarse-grained soils
are more stable as a
foundation material than
silt or clay.
35.
shearing strength of a
soil
measure of its ability to resist
displacement when an external
force is applied, due largely to
the combined effects of cohesion
and internal friction
36.
Sloped sites &
excavation of a flat site
unconfined soil displace laterally
37.
Soil Classification
methods vary depending on grain
size, huge difference in physical
properties between soil types,
classification helps defining
behaviors
38.
soil classification
systems
AASHTO (roads), USCS - Unified
Soil Classification System
(structure)
39.
Soil collected through
test pits or test borings
can be used to
understand:
4. All answers provided are
correct
The portion of total stress carried by water
in continuous void spaces (equal intensity
in all direction)
1. Extent of soil
consolidation under
loading
2. Permeability of soil
3. Water content of soil
4. All answers provided
are correct
40.
Soil is a three-phase
system consisting of
what phases?
1. clay, silt, sand
2. solids, voids, water
3. water, solids, air
3. water, solids, air
41.
soil profile
the diagram of vertical section of soil from
the ground surface to the underlying
material
42.
Soil Strength
= f = cohesion friction
43.
soil type
cohesive (clay - resist some tension) vs
noncohesive (sand and gravel)
44.
The soil
underlying a
building site
consist of superimposed layer (mix of soil
types due to weathering or deposition)
45.
solids
different size, shape, angularity
46.
A subsurface
investigation
includes
the analysis and testing of soil disclosed by
excavation of test pit up to 3m deep or
deeper test boring
47.
A subsurface
investigation
is conducted
to
understand the structure of soil, its shear
resistance and compressive strength, its
water content and permeability, and the
expected extent and rate of consolidation
under loading
48.
49.
Suitability of
soil as a
foundation
materials
the stratification, composition, and density of
the soil bed & variations in particle size, and
the presence or absence of ground water
Total stress
resisted by 1. soil skeleton (due to contact
forces between soil particles (effective
stress) and 2. pore water pressure (unit
weight of water * height of water column)
50.
total stress
The total vertical stress acting at a point
below the ground surface is due to the
weight of everything lying above
51.
Total stress at
a point is
1. resisted by the soil skeleton and the water
in the voids
1. resisted by
the soil
skeleton and
the water in
the voids
2. resisted by
the water in
the voids
3. resisted by
the soil
skeleton
52.
Total stress
at a point is
due to
1. the weight of everything acting above that
point
1. the weight
of
everything
acting
above that
point
2. the weight
of the water
in the voids
above that
point
3. the weight
of the soil
solids above
that point
53.
Total Stress
(vertical
stress)
stress imposed below the ground due to
everything (including the soil above it) above
the point of interest = sum of unit weight *
depth +surface loads
54.
two broad
classes of
soils
coarse grained soils and fine grained soil
55.
USCS
classification based on 1. size of soil grain, 2.
distribution or gradation of soil grains (well
graded: well distribution of different soil grain
size), 3. organic components (organic: behave
weird - remove for the stable supports), 4.
behavior of fine particles (sticky or not)
56.
USCS fine
classification
1. water content (moisture content), 2.
Atterberg limits
57.
USCS fine
classification
- Atterberg
limits
1. Liquid Limit: water content that separates
liquid and plastic status, 2. plastic limit: water
content that separates plastic and semi solid
58.
USCS fine
classification
- plastic
index
differences between liquid limit and plastic
limit
59.
USCS fine
classification
- Water
content
liquid (High water content - flow), plastic
(medium water content - sticks), solid or semi
solid (low water content - crumbles)
60.
USCS
gradation
classification
well graded, poor graded, gap graded
61.
USCS gradation- Gap graded
Some sizes are not
existed in the soil
62.
USCS gradation - Poorly graded
(uniformly graded)
soil in narrow bands of
sizes, lots of similar
sizes
63.
USCS gradation- well graded
wide range of sizes,
can pack closely
together
64.
USCS soil classification based on
grain size
Boulder (>12''),
Cobbles(>3"),
Gravel(>#4),
Sand(>#200), Fine (clay,
silt)
65.
Void ratio is:
2. ratio of the volume
of the voids to the
volume of the solids
1. ratio of the volume of the voids
to the total volume
2. ratio of the volume of the voids
to the volume of the solids
3. ratio of the volume of water to
the volume of the voids
66.
Voids
consists of water
(bottom) and air (top)
67.
Void Spaces
Continuous and
occupied by water, air,
or both
68.
Volume of Soil
Solid particle
distributed randomly
with void spaces in
between
69.
The water table
level beneath which
the soil is saturated
with groundwater
70.
Which of the following statements
is incorrect?
3. In general, bearing
capacity decreases
with increased soil
density.
1. Clay soils can be unstable
because they may shrink and
swell with changes in moisture
content.
2. Clays tend to be impervious to
fluids.
3. In general, bearing capacity
decreases with increased soil
density.
4. The water table is the level
beneath which the soil is saturated
with groundwater.
71.
Which soil classification would be expected to
have the highest bearing capacity?
1. Silt
2. Sand w/ fines
3. Clean gravel
4. Clay
3. Clean
gravel
Exam #1 - Soil Mechanics
Study online at quizlet.com/_65dp5q
1.
5 main objectives of
compaction:
1. Detrimental settlements can be
reduced/prevvented
2. soil strength can be increased (and
slope stability improved)
3. Bearing capacity of pavements is
increased
4. Hydraulic conductivity can be
dereased
5. undesirable volume changes can be
controlled (i.e. frost heave, swelling,
shrinkage)
19.
D30
grain size diameter at which 30% passes
20.
Define
Compaction
the densification of soils and rocks by the
application of mechanical energy
21.
Degree of
Saturation
S
22.
Degree of
Saturation
Calculated:
Vw/Vv * 100
23.
Densification
Reduction in void ratio
2.
A-line
separates out clay and silts
24.
Density
p
3.
Atterberg Limits
for fine grained soil classification.
Classify based on water content at
critical stages of engineering behavior
and we compare these water contents
to natural water content.
25.
Density = ?
M/V
26.
Density Index
Definition?
Uses dry density or dry unit weight to
characterize soil with respect to max/min
density
27.
density of
buoyant soil = ?
saturated density - density of water
28.
density of
buoyant soil = ?
density of dry soil ( 1-(1/Gs))
or
density of dry soil (1-(density of
water/density of solids))
29.
Density of dry
soil (s=0) = ?
Ms/Vt
or
density of solids/(1+e)
30.
density of
saturated soil
(s=100%) = ?
Mt/Vt
Based on how soils
are made up of (i.e.
coarse/fine grained
materials)
differentiates ___?
characteristics and behavior
5.
Can data be plotted
above the ZAV
line?
no
6.
Cc
coefficient of curvature
7.
Coefficient of
Curvature (Cc)
((D30)^2)/D60*D10
8.
Coefficient of
Uniformity (Cu)
D60/D10
31.
density of
solids = ?
Ms/Vs
9.
cohesionless
easily separate one particle from
another (silts/sands)
32.
density of total
soil = ?
Mt/Vt
10.
compaction is a ___
soil stabilization
method
mechanical
33.
density of
water = ?
Mw/Vw
34.
Weight of solids - buoyant force
Compaction of finegrained materials is
a function of what 4
variables?
dry density, water content, compactive
effort, and soil type (gradation and
percent fines)
Effective
Weight = ?
35.
field dry
density
pd-max
Compactive Effort
measure of mechanical energy applied
to a soil mass
36.
% FINER = ?
100-%coarser
37.
Vs density of water g
13.
C (soil classification)
clay
Force buoyant
=?
14.
Cu
coefficient of uniformity
38.
Geotechnical
Grouting
15.
Cu = 1
uniform grainsize soil
Process where voids are either filled in
their natural environment or voids are
created and replaced.
16.
Cu = 2,3
poorly graded (few grain sizes)
39.
Gravel
17.
Cu > 15
well graded (wide variety of grain
sizes)
G (soil
classification)
40.
Gs range
2.6-2.8
effective grain size
41.
High Plasticity
LL>50
4.
11.
12.
18.
D10
42.
43.
44.
How are void ratio and porosity
related?
n = (e/1+e)
e = (n/1-n)
How is distribution of different
grain sizes plotted? Give
parameter and the scale used.
Grain diameter in log
scale, percent by mass
(or weight) in linear scale
How is plastic limit determined?
The water content when a
thread of soil just
crumbles at a diameter
of 3mm (1/8")
68.
Porosity
n
69.
Porosity Calculated:
Vv/Vt * 100
70.
P (soil classification)
poorly graded
71.
Range of different shapes
of particles
Very angular --> Well rounded
72.
Range of water contents
over which the soil
behaves as a plastic
Plasticity Index
45.
H (soil classification)
high plasticity
73.
Relative Compaction
RC
46.
If given shelby tube example...?
Start with finding total
volume
Vt = (pi * d^2 )/4
74.
Relative density
Dr
75.
Relative Density
Definition?
It uses void ratio
76.
reported to the whole
number (no % symbol)
LL and PL
77.
shaded region in liquid
limit and plasticity index
plot:
could behave as either
78.
soils are made up of ____?
coarse grained and fine grained
materials
79.
Solid phase of soil is
comprised of what 6
particle types
differentiated by grain
size?
Boulders, cobbles, gravels,
sands, silts, clays
80.
Specific Gravity = ?
density of solids/density of
water
47.
Impact Compaction
Compaction/densification
from shearing fine
grained soils
48.
Index Density
Id
49.
Is the line of optimums parallel
to S = 100% curve?
True
50.
Kneading Compaction
compaction/densification
from particle vibration
51.
LI
liquidity index
52.
LI < 0
brittle soil
53.
LI = ?
(w-PL)/(PI)
54.
LI = 1
liquid limit
55.
LL
liquid limit
56.
Low Plasticity
LL<50
81.
specific gravity of solids
Gs
57.
L (soil classification)
low plasticity
82.
S (soil classification)
sand
58.
maximum dry density
pd-max
83.
Static Compaction
59.
Most of the mass-volume
relationships for soils are
independent of sample size are
often dimensionless
True
Compaction/densification
resulting from pressure
84.
Steps for solving phase
diagrams:
60.
M (soil classification)
silt
61.
Optimum moisture content
Opt water content occurs
when the dry density is
maximum
62.
Optimum water content
wopt
63.
O (soil classification)
organic soil
64.
PI
plasticity index
65.
PI = ?
LL - PL
66.
PL
plasticity limit
1. List information known
2. Draw phase diagram fill in
unknowns and knowns
3. Try to avoid big formulas
4. If no masses/volumes are
given you can assume either
one volume or one mass
5. Fill in one side of the diagram
until you get stuck. Then cross
over to other side using one of
the p's or Gs
6. Write out equations in
symbol form.
7. Check units/reasonableness
of your answer
67.
Poorly Graded or Well
Graded??
Check Cu first THEN
check Cc. Cc will
overrule Cu.
85.
STUDY FIGURE 2.4 BE ABLE TO
REPLICATE VALUES AND
REDRAW CHART ON EXAM!
...
86.
U-line
upper limit for real soils
87.
Unit weight
y
88.
Unit weight = ?
W/V
89.
Vibratory compaction
Compaction/densification
from a falling weight
90.
void ratio
e
91.
Void Ratio Calculated:
Vv/Vs
92.
Voids
space not occupied by
solids (air phase and
water phase)
93.
water content
w
94.
water content calculated:
Mw/Ms * 100
95.
Water content can be
calculated using either the ratio
of mass or ratio of weight of
water to solids
True
Water content is the ratio of
the amount of ____ present in a
soil volume to the amount of
soil grains based on the ____
mass of the soil, not the ____
mass.
water, dry, total
97.
Water content representative
of a lower limit of a soil's
viscous flow
Liquid Limit
98.
water content representative
of the soil's lower limit of a soil's
plastic state
Plasticity Limit
99.
What 3 things does texture
depend on?
Relative particle size,
relative particle shape,
and range/distribution of
particle sizes
100.
What are the 3
components/phases of soil?
solids, water, air
101.
What constitutes a poorly
graded soil?
It has an excess or
deficiency of certain
sizes
102.
What constitutes a well graded
soil?
It has a normal or near
normal distribution of a
wide range of grain sizes
103.
What device is used to
determine grain size of
particles less than 0.075mm in
equivalent diameter?
Hydrometer
96.
104.
What differences
between Methods A
of the Standard and
Modified Proctor
compaction tests
contribute to the
difference in
compactive effort
hammer weight, hammer drop
weight, number of layers
105.
What does the degree
of saturation tell us
about the voids within
a soil mass?
The total percentage of void space
that contains water
106.
What is density?
The ratio of mass to volume.
107.
What is equation to
convert density to
unit weight?
p*g=y
108.
what is relationship
between s, e, w, ps?
s e = Gs w
109.
What is Relative
Compaction?
It is an end product specification
that is based on ratio of the field
dry density to max dry density for
a soil. It is used to control the
density achieved in the field. It
provides a baseline criteria to
ensure soil is within density
specification.
110.
What is the name of
the plots that the
proportional
distribution of
different grain sizes
is/are commonly
shown?
Cumulative Frequency Diagram,
Histogram, gradation curve
111.
What is the range of
grain sizes that are
classified using U.S.
Standard Sieves
0.075 mm to 75 mm
112.
What is unit weight?
The ratio of weight to volume
113.
When is a soil
assigned a dual
symbol under the
USCS rubric?
When the fraction of soil that is
fines is between 5% and 12%
114.
When the natural (e.g.
field) water content is
such that the soil
behaves as a plastic
0<LI,1
115.
When the natural (e.g.
field) water content is
such that the soil has
brittle behavior
LI<0
116.
When the water content is such that the soil behaves as a liquid
LI>1
117.
The zero air voids curve represents ___ saturation
100
Biochem- Chap 16- Introduction to soil structure
Study online at quizlet.com/_98n43x
1.
Describe a
crumb:
-1 mm - 6 mm
-fairly porous spheres
-not joined to other aggregates
14.
What are
limestones
made of?
Common silts but may also have clay and
sand. Usually thin.
2.
Describe
Blocky-
-5 mm- 75 mm
-like blocks
-easily fit closely together
-often break into smaller blocks
15.
What are
sandstones
made of?
Sandy soils but dependent upon cementing
agent
16.
Describe
Columnar:
- like columns
- rounded caps
- fit closer together
What are
shales made
of?
Silts and clays
3.
17.
Describe
Prismatic:
- column-like prisms
- easily fit closely together
- sometimes break into small blocks
What are the
four main
components
of soil?
Air, water, organic materials, minerals
4.
5.
Descrive a
Platy:
-1 mm- 10 mm
-like plates, often overlapping which hinders
water passing though
18.
Silicate, Manganese oxides, iron oxides,
aluminium oxides
6.
Give 2 reasons
why we care
about soils:
1. Soils are the fundament of agriculture and
crop production
2. Soils are very important at storing carbon
What are the
main minerals
in clay
formation?
19.
Sand, silt and clay
How are soils
distinguished
from inert
rock material?
-the presence of microbial, plant and animal
life
- a structure that reflects pedogenic
processes
- a capacity to response to environmental
changes
What are the
three main
classes of
soils?
20.
Identifying the Hue, Value and Chroma
How is a soil
sedimentation
analysis
carried out?
by suspending the soil sample in a large
quantity of water. The different size fractions
sediment differently, depending on their
density and weight.
What are the
three
requirements
for identifying
soil?
21.
- wildfires
- hydrophobic plant residues
If the soil is
coarse will the
water seep
into it faster
or slower?
Faster
What can
cause
hydrophobic
soils?
22.
What acronym
describes soil
properties?
f(CL,O,R,P,T)
What causes
soils to be
greyish and
slightly
blueish?
Iron, in its reduced state due to the anoxic
conditions. When roots deliver oxygen deep
into the roots this will oxidise the soils
forming orange iron oxyhydroxides
(FeOOH)
23.
brown to black
What are
basalts made
of?
Silt and clay soils
What colour
are organic
rich soils?
24.
12.
What are
granites made
out of?
Locally sandy soils
What does
allochthonous
mean?
Material that has come from elsewhere
Air: loess, sands and ash fall
water: exposed lakes and river sediments,
saltmarshes and mangroves
Ice: glacial deposits
13.
What are
infiltrometers?
And how do
they work?
They are used to measure the rate at which
water can infiltrate soil. A ring is driven into
the soil covering a defined area, and the
water is kept constant. The volume of water
per area per time is calculated.
25.
What does
autochthonous
mean?
local parent rock, from parent rock below
site, nearby, or at some distance but
delivered by wind
7.
8.
9.
10.
11.
26.
What does 'clorpt'
stand for?
cl = climate
o = organisms
r = relied, topography
p= parent material
t = time
27.
What does soil form
the interface
between?
The inanimate geosphere and the
biosphere
28.
What does soil water
depend on?
Water supply (precipitation or
groundwater), infiltration, particle
size and hydrophobicity
29.
What does the large
surface area of sand
grains mean?
That it has a low nutrient content
and low capacity to retain nutrients
30.
What does the l, s, v,
and a stand?
l = ecosystem properties
s = soil properties
v = vegetation properties
a = animals
31.
What factors are the
rate of settlement
controlled by?
gravity, viscosity, density of liquid
and particle radius and density
32.
What gives greyish
soils?
Reduces iron
33.
What gives rise to red
soils?
Ferric oxohydroxide
34.
What gives rise to
yellow soils?
Hydrated iron oxides
35.
What is Chroma?
how weak or strong a colour is
36.
What is edaphology?
the science describing the
interaction of soil with the living
components of an ecosystem
37.
What is Hue?
The colour
38.
What is pedology?
the study of soils in their natural
environment
39.
What is sedimentation
velocity proportional
to?
The square of the sedimenting
particle radius.
40.
What is sediment
velocity inversely
proportional to?
The viscosity of the liquid. A high
viscosity results in a low
sedimentation speed
41.
What is soil water
crucial for?
-mobility of soil life and source of
water for plants
- soil structure and chemistry (clay
hydration)
- mineral solubility and release
- principal cause of soil horizon
formation
42.
What is Valye?
How light or dark the colour is
43.
What law is used to measure the
velocity of sedimentation for
spherical particles in a viscous
liquid?
Stoke's Law
44.
What nutrients does soil mainly
retain?
Nitrogen and water
45.
What rock types are found in
ACIDIC soil?
Granites and
Sandstones
46.
What rock types are found in
BASIC soil?
Basalts, Shales and
limestones
47.
Where will organic material
normally be found in soil
sedimentation analysis?
It will float, as it is very
light.
48.
Why are anoxic conditions bad in
terms of soil?
- prevents the
degradation of organic
matter
-no bioturbation
-stimulate methane
formation, since
methanogenesis will
be stimulated
-
49.
Why is good drainage good for
soils?
It allows air to diffuse
through the soil to
prevent it becoming
anoxic
50.
Why so clay soils have a high
water content?
They have small pore
spaces holding water
by capillary forces
Soil Mechanics
Study online at quizlet.com/_1as2l2
1.
Activity (A)
A= Ip/(%Clay)
11.
Clay Minerals
These are small crystalline substances with a
distinct sheet like structure producing plate
shaped particles. Many clay minerals put
together form a sheet with a negative charge.
The more clay minerals present the more
plastic the clay is
2.
Air content
(A)
Is the volume of air to the total volume of soil
12.
Clay Size
3.
Air entry
value
Defined as the limit to the negative porewater
pressure that be maintained in the soil without
sucking air into the soil
Most classification of clay describe be less
than 2 micrometers. However some clay
minerals may be greater than 2 and some
less.
13.
Clay Soil
Soil behave as a clay because of its
cohesiveness and plasticity even though the
mineral content may be small
14.
Coarse
grained soil
Gravel and sand
15.
Coefficient
of Uniformity
(Cu)
D60/D10 (Where the 60 and 10 indicate the
amount of percent passing)
16.
Compaction
Compaction is the removal of air
It involves increasing the degree of saturation
of the soil by reducing the volume of air in
the voids
AEV increases with decreasing pore size. Ex
the smaller the pore size the higher the AEV
FIne grained soils may remain saturated for
several meters above the water table with
pore water pressure decreasing until the AEV
is reached
4.
Alumina
Octahedron
Base unit of Clay mineral composed of 6
hydroxyl and 1 aluminum
5.
Artesian
condition
Upward flow
6.
Assumptions
in Laplace's
equation
Darcy's law is valid
Soil is saturated and homogenous
Water and soil is incompressible
7.
Atterberg
limit
The objective of compaction is t improve the
engineering properties
Consolidation and compaction are not the
same thing.
Consolidation refers to the removal of water
from saturated clay
17.
Consolidation
Is reduction in the volume of water in the soil
18.
Constant
head
permeability
test
Soil placed into cylinder with inlets and
outlets at the top and bottom
Define the water contents at which the soils
will change consistency (Solid, Semisolid,
plastic, Liquid)
8.
Bulk density
Units are Kg/M^3
9.
Capillary
rise
Rise will be higher when d is smaller
porewater pressure above the water is
negative due to capillary action
10.
Clay
The pressure is taken along points of the
cylinder using manometers at known
distances from each other
Ratio of the total mass to the total volume
p=M/V
Mostly flaked-sharped microscropic and
submicrosopic particles of mica, clay minerals,
and other other minerals
The flow rate Q is determined by timing how
long it takes to fill x amount of fluid in y time
19.
Degree of
saturation
% of voids filled with water
Sr=Vw/Vv
Vw=Volume water
Vv=Volume voids
20.
Density
Index (Dr)
Also know as relative density, is used for
sands and gravels to express the relationships
between the in situ void ratio (e) of a sample
to the limiting values
29.
Hydraulic
Conductivity
Depends on:
Size and shape of particles
soil structure
viscosity of liquid
temp of fluid
clay structure (Flactulated or non)
Degree of saturation Sr
30.
Hydrometer
test
- Performed on grains that are smaller than
0.075mm or smaller
- Based on stokes law: Larger particles travel
faster
- A plot of suspension density VS elapsed
time gives the grain size distribution
31.
Illite
-Common mineral but varies in chemical
composition
-Particles flaky, small, diameter similar to
montmorillonite but thicker
-Moderate shrinking and swelling when
introduced to water
-There are potassium bonds allowing water
to enter the clay
32.
Immediate
settlement
Once the stress change is known for any
depth, elastic strains can be calculated using
Hooke's law
33.
Kaolinite
-Particle size up to 3 micrometers
-Low shrinking/swelling (Expands and contracts the least out of the clays)
-This is used in pottery
-Hydrogen bonds prevent hydrations (Doesn't
let water in) and produces many layers with
large surface areas
34.
Liquidity
Index
Gives an indication of the in situ consistency
of a fine grained soil
Depends on the type of soil
Dr= (emax-e)/(emax-emin)
21.
Dry density
Is the ratio of the mass of the solids to the
total volume (Dry density has no physical
meaning in terms of its not the actual density
of the soil)
Dry density is simply an indicator of how
tightly the solid particles of soil are packed
together
Pd=Ms/V
Ms=Mass of solid
V=Volume
22.
Elevation
Head
At a given point is the relative height of the
point with respect to the chosen datum
23.
Fabric
Structure of
Clayey Soils
-Dispersed: A broken house of cards (Can
occur in a salty non polar solution)
-Flocculated: Imagine a house of cards of ions
touching, Positive to negative ect (Often in a
freshwater solution)
This shows the change in volume of the soil
that can occur
Falling head
permeability
test
Determining the change of height of water
above a tank as a function of time.
25.
Fine grained
soil
Clay and Silt
26.
Flow nets
Total head is constant along equipotentials
24.
If 1 <LI then you're close to the liquid limit
35.
Normally
Consolidated
A soil that has never previously been subject
to a greater vertical effective stress.
Very low shear strength and high
compressibility
There is no flow along equipotentials
Lies on the virgin curve
A pair of adjacent flow lines define a flow
channel where rate of flow is constant
27.
Gravel
Piece of rocks with occasional particles of
quartz, feldspar and other minerals
28.
Gravimetric
Water
content
Mass of water/ Mass of solid(dry)
36.
Oedometer
test
A soil sample has a load applied to it
There is two way drainage
Very little initial compression
Increments are usually doubled every step
37.
One
dimensional
consolidation
Increments of vertical strain are equal to
increments of volumetric strain
38.
Over
consolidated
soil
A soil that has been previously subjected to
a vertical effective stress greater than its
present effective stress
45.
46.
Over
consolidatioion
ratio
40.
Plasticity
-Ability of a soil to undergo irrecoverable
deformation while remaining at a constant
volume. This is without cracking or
crumbling
Plasticity Index
The water content range over which a soil
remains plastic.
The more clay the higher the plasticity
index.
If the hydraulic gradient is high enough, the
seepage force can be equal to the
gravitational force acting on the soil.
Therefore it will have zero effective stress
and no strength
47.
Sand
Particles are made of mostly quartz and
feldspar and other mineral grains
48.
Saturated
density (Psat )
Is simply the bulk density of the soil for Sr=1
Psat can be determined by substituting Sr=1
in the expression for bulk density p
49.
Secondary
Consolidation
or creep
Result of plastic adjustment of the soil fabric.
- This depends primarily on the water
content, and the type and amount of clay
minerals present in the soil
41.
Quick
Condition
NC = 1
OC>1
OCR <1
Ratio of maximum past vertical effective
stress to current vertical stress
Settlement is caused by a change in volume
in the saturated soil. A decrease in void ratio
as water is expelled from the void spaces
This occurs in more soils by the coarser the
soils the faster it occurs
Less compressible and have higher shear
strength
39.
Primary
consolidation
Plastic deformation that occurs at a constant
effective stress.
This occurs after the excess pore pressure
has dissipated and the effective stress is
constant.
50.
Silica
tetrahedron
Range of water content ( between liquid
and plastic limits) over which a fine grained
soil exhibits plastic behavior
51.
Silt
Microscopic soil fractions that consists of
very fine quartz grains that are fragments of
micaeous minerals
Ip= WL-Wp
52.
Smectites
-High surface area due to small and thin
particles produced by water molecules and
exchangeable ions entering between layered
units ands separating them
-Water readily attracted to mineral
- Very high swelling and shrinking
53.
Types of
compaction
Static-Evan
Kneading
Vibratory-Tobi
Dynamic
42.
Poorly Sorted
Well graded
43.
Porosity (n)
Defined as the ratio of the volume of voids
to the total volume of the soil
n=Vv/V
Vv=Volume of voids
V= Total volume
n= e/ (1+e)
Where e is the void ratio
44.
Pressure head
Basic Unit of Clay Minerals Silicon (1) and (4)
Oxygen
A high plasticity index does not
necessaryily mean it will be plasticically
deformable, that depends on its water
content
Is independent of the chosen elevation
datum
54.
Unified Soil Classification System
(USCS)
S: Sand
G: Gravel
M: Silt
C: Clay
Courses Grained Fine Grained:
W: Well graded L: Low Plasticity
P: Poor graded H: High plasticity
55.
Void Ratio (e)
Is the ratio of the volume of voids to the volume of solids
e=Vv/Vs
Vv=Volume voids
Vs= Volume of solids
Volume of solids and mass of solids will never change
56.
Volumetric water content (theta)
Defined as the ratio of volume of water to total volume
Theta= Vw/V= (Vv)fkadjfkljsd
57.
Water Content (W)
Defined as the ratio of the mass of water to the mass of solid particles in the soil.
W= Mw/Ms
58.
Well sorted
Poorly graded
59.
What holds water into Clay?
The surface tension in the clay keeps the water in the clay. This is due to the very small pore
sizes of the clay.
Soil Classifications
Study online at quizlet.com/_6fxdrt
1.
>60% clay
very-fine
31.
2.
35-60% clay
fine or
clayey
Ex. fine-loamy, clayey or fine, coarsesilty
particle size
class
32.
fragipan
frag
33.
has plinthite (firm Fe masses)
Plinthic
34.
Hawaii region, toxic, extremely
weathered; much Fe + Al oxides, very
low Base saturation
Oxisols
3.
Accumulation of calcium carbonates in subsoil
(Bk)
Calcic
4.
Accumulation of Fe and Al oxides and kaolinite
(Bo)
Oxic
5.
Accumulation of humus, Fe and Al oxides
(sesquioxides) (Bhs, Bh, Bs)
Spodic
35.
histic surface; decomposed plant tissues,
found under conifer vegatation
Histisols
6.
Accumulation of kaolinite clay in subsoil, a
specific type of argillic horizon (Bt )
Kandic
36.
How does USDA classify soils?
7.
Accumulation of sodium (Na) in the subsurface
Natric
uses color, clay
content, bases,
oxides
8.
Accumulation of translocated (illuviated) clay
in subsoil (Bt )
Argillic
37.
How many orders of soils are there?
12
38.
humid, well drained Ex. Udult, Udalf
ud
9.
acidic, low base saturation, spodic
Spodosol
39.
-id
aridisol
10.
acid vs. nonacidic
acidity
40.
-ist
histisol
11.
Aids in communication about soils, groups
similar soils together, useful in land
management
Why to
classify
soils
41.
light colored, lower in OM, thin (<10"),
Base saturation of <50%
Ochric
42.
loamy, <18% clay
coarse-loamy
12.
-alf
alfisol
43.
loamy, 18-35% clay
fine-loamy
13.
-and
andisol
44.
Mediterranean climate (wet/dry)
Xeric
14.
argillic, Base saturation >35% in argillic
Alfisol
45.
mediterranean dry ex. Xeroll, Xeralf
xer
15.
argillic in aridisol ex. argid
arg
46.
Moist, well drained, not wet at surface
Udic
16.
argillic in Mollisol
argi
47.
Mollic surface, Base saturation >50%
Mollisol
17.
arid climate, salt accumulation (calcic and/or
gypsic, natric); often with cementation
Aridisols
48.
The next youngest soil; has cambic, weak
blocky structure
Inceptisol
18.
Churning soils; high smectite clay, high
shrink/swell, cracks
Vertisols
49.
-od
spodosol
19.
cold ex. cryod
cry
50.
-oll
mollisol
20.
Compact, yet brittle subsurface horizon (Bx,
Btx)
Fragipan
51.
-ox
oxisol
52.
Geliosols
21.
deep, organic surface horizon (Oi, Oe, Oa)
Histic
permafrost soils; freeze-thaw,
cryoturbation
22.
deposited by river ex. fluvent
fluv
53.
sand ex. psamment
psamm
23.
discontinuous fragipan
fragic
54.
saturated from bottom up
endo
24.
Dominants soils of the south east, argillic; Base
saturation of <35% in argillic
Ultisols
55.
saturated from surface down
epi
56.
siliceous, smectitic, kaolinitic
mineralogy
25.
drier Ex. Ustoll, Ustox
ust
57.
silty, <18% clay
coarse-silty
26.
drier than udic
ustic
58.
silty, 18-35% clay
fine-silty
27.
-el
gelisol
59.
28.
-ent
entisol
super active, active, semi active,
subactive
cation exchange
activity
29.
-ept
inceptisol
60.
thermic, mesic, hyperthermic, frigid
temperature
regime
30.
-ert
vertisol
61.
thick (>10"), dark colored, base saturation
>50%
Mollic
62.
thick (>10"), dark colored, but Base saturation <50%
Umbric
63.
thick argillic
pale
64.
thin argillic
hapl
65.
tongued
gloss
66.
tonguing + wetter than typical
Glossiaquic
67.
tonguing ex. Glossic Fragiudult
glossic
68.
typical for great group
typic
69.
-ult
Ultisol
70.
Very dry, in arid regions
Aridic
71.
Very light (white) colored subsurface horizon (leached and bleached) (E)
Albic
72.
volcanic ash; not dense
Andisols
73.
Weak development of structure and color in subsurface (Bw)
Cambic
74.
Wet at soil surface for long periods, result in gleying (process in which soils
grey)
Aquic
75.
wet at surface Ex. Aquert, Aquult
aqu
76.
wetter than typical (in subsoil)
aquic
77.
What are the 2 old soils?
Ultisols, Oxisols
78.
What are the 2 young soils?
Entisol, Inceptisol
79.
What are the 3 mature soils?
Mollisol, Alfisol, Spodosol
80.
What are the 5 unique soils?
Vertisols, Aridisols, Histisols, Gelisols,
Andisols
81.
The youngest soil; no B
Entisol
soil terms - Classification
Study online at quizlet.com/_2szql8
1.
A
The ___-line generally separates the more clay-like materials from silty materials
and the organics from the inorganics.
2.
AASHTO (American Association of State
Highway and Transportation Officials)
Classification system mainly used in pavement and highway applications.
3.
All of these may impact the time rate of
consolidation
Thickness of soil, permeability of soil, drainage of the soil body, presence of a
surcharge
4.
alluvial deposit
soil deposited by moving water
5.
Angle of Internal Friction
Measure of the ability of a soil sample to withstand shear stress
6.
Cc
Coefficient of Curvature
Cc = (D30^2 / (D10*D60))
7.
Coarse grained soil
less than 50% by weight passes through a No. 200 sieve
8.
Coefficent of Uniformity (Cu):
Cu=D60/D10
where: D60 = grain diameter (in mm) corresponding to 60% passing by mass
and,D10 = grain diameter (in mm) corresponding to 10% passing by mass.
• Note: if D60 = D10, Cu = 1, all particles between 10% and 60% are the same size.
9.
Coefficient of Curvature (Cc):
Cc=D30^2/(D10*D60)
where: D30 = grain diameter (in mm) corresponding to 30% passing by mass.
10.
Cohesion
Attraction of one water molecule to another resulting hydrogen bonding
11.
Cohesive
...
12.
Cohesive soil types
high clay content, can be excavated with vertical side slopes
13.
compacted soil conditions
material after compaction
14.
Consolidated rock/bedrock
Dense continuous mass of minerals that can only be removed by drilling or
fracturing.
15.
Consolidation
Extrusion of water particles from the soil as a result of increased loading
16.
Construction contracts often specifically
require that the contractor acknowledges:
The information available in soil reports may not be complete
17.
Cu
Coefficient of Uniformity
Cu = (D60 / D10) Smaller number = more uniform
18.
Differential Settlement
Subsidence of the various foundation elements of a building at differing rates.
19.
Dx
Grain size which allows X% of soil to pass through
20.
Effective particle size (D10):
• Denotes the grain diameter (in mm) corresponding to 10% passing by mass.
• The effective size of a granular soil is a good measure to estimate the hydraulic
conductivity and drainage through soil.
21.
Fabric
...
22.
Fine grained soil
more than 50% by weight passes through a No. 200 sieve
23.
Five fundamental materials of soil
gravel, sand, silt, clay, organics
24.
flow index (FI)
slope of the flow curve, rate at which soil loses strength when water content is
raised
25.
For well graded Soil:
a) Cu > 4 for gravel & Cu > 6 for sand
b) 1<Cc<3
26.
Foundation Factors for Immediate Settlement
Problems
...
27.
Frictional
Internal strength which some soils rely primarily on
28.
Gap Graded:
a proportion of grain sizes within a specific range is low (it is also poorly graded).
29.
Gap graded
...
30.
gradation
W and P are _____ symbols.
31.
Grain Size Distribution
Look at diagrams in lecture notes!!!
32.
granular soil types
gravel/crushed rock, can not be excavated with vertical side slopes
33.
Graph Problem
Shear on the Left
Normal on the Bottom
34.
hydrometer analysis gives
the diameter of an equivalent sphere that would settle at the same rate as the soil particle.
35.
Hydrometer test:
D=(18n/(ps-pw))^(1/2) * (L/t)^(1/2)
Where:
D = diameter of soil particle (mm)
n = viscosity of water
ps= density of soil particles
pw= density of water
L = 16.29-0.164R (cm)
R=Hydrometer reading
t = time (min)
• Foragivensoil,sinceL&tarethe variables, the above eqn can be written as:
D=K(L/t)^(1/2)
Where K is a constant --> Table 3 ASTM D422
36.
Hydrometer test: (description)
• Hydrometer analysis is based on the principle of sedimentation of soil grains in water.
• When a soil specimen is dispersed in water, the particles settle at different velocities,
depending on their shape, size, weight, and the viscosity of the water.
• Hydrometer test is conducted in accordance to ASTM D422:
-50 or 100 g oven dried soil specimens is poured in a 1000 ml sedimentation cylinder.
-A dispersing agent is added and then the volume of dispersed soil is increased to 1000 ml
by adding distilled water.
-Hydrometer is placed in soil suspension at time t giving the amount of soil that is still in
suspension.
-The soil particles in suspension at a depth L will have a diameter smaller than D.
-By knowing the amount of soil in suspension, L, and t, we can calculate the percentage of
soil by weight finer than a given diameter.
37.
If Cu and Cc do not meet both of
the criteria above, the soil is
poorly graded
38.
Immediate Settlement
Know formulas
39.
in-situ
material in its natural state also known as "in-place"
40.
Lateral soil pressure load
Horizontal pressures of the earth and groundwater against basement walls
41.
liquidity index (LI) (edit )
(natural water content - PL)
PI when LI > 1 soil is at or above liquid limit
42.
Liquid limit
Level of moisture before reaching a liquid state
43.
liquid limit
H and L are _____ symbols.
44.
Liquid Limit (LL)
max water content at which soil behaves as a plastic solid
45.
loess deposit
windblown soil deposits
46.
Loose soil conditions
material that has been excavated or loaded
47.
manual soil test
plasticity, dry strength test, thumb penetration test, pocket
penetrometer, shear vane
48.
organic matter
dead plant and animal material in various stages of decay
49.
Organic soils
Soil containing decayed vegetable and/or animal matter;
topsoil.
50.
Phases of Settlement
Immediate Settlement
Primary Consolidation Settlement
Secondary Compression Settlement
51.
Plasticity Index (PI)
PI = LL - PL range at which soil behaves as a plastic solid
52.
Plastic Limit (PL)
min water content at which soil behaves as a plastic solid
53.
Poorly Graded:
either excess or a deficiency of certain sizes, or most of the
particles about the same size. (i.e. uniform soil)
54.
Poorly Graded
uniformly graded (narrow range in particle size)
"Gap Graded" - missing size(s)
55.
Relative Density (Dr)
Dr = ((emax - e ) / (emax - emin))
56.
Results from the grain size distribution curve are used to
describe the proportion of soil constituents in the sample. To
describe the sample in words, use:
(Canadian Foundation Engineering Manual)
noun ->gravel, sand, silt, clay--> > 35% and main fraction
"and" -> and gravel, and silt, etc. --> > 35%
adjective gravelly, sandy, silty, clayey --> 20% - 35%
"some" some sand, some silt, etc. --> 10% - 20%
"trace" trace sand, trace silt, etc. --> 1% - 10%
For example, a soil with 30% clay, 45% silt, 18% sand, and 7%
gravel would
be described as a "Clayey silt, some sand, trace gravel".
57.
Shear Strength
Soils ability to resist sliding along internal surfaces within a
mass of the soil
58.
Shear strength
The resistance due to friction preventing soil from shifting.
59.
Shear Strength test methods : Field
Vane Test
Standard Penetration Test
Penetrometer Test
60.
Shear Strength test methods : Lab
Unconfined Compression Test
Direct Shear Test
Triaxial Compression Test
61.
shrinkage limit
water content below which no further volume change occurs
during drying
62.
Sieve analysis gives:
the intermediate dimensions of a particle;
63.
Sieve analysis test:
• Particle size distribution obtained by shaking a dry sample of
soil through a series of woven-wire square-mesh sieves with
successively smaller openings.
• Since soil particles are rarely perfect spheres, particle
diameter (or size) refers to an equivalent particle diameter as
found from the sieve analysis.
• Nested sieves are used for soils with grain sizes larger than 75
m. For finer soils (silts and clays) the hydrometer test is used.
64.
Sizes of different types of Soils
Soil Type - USCS Grain Size (mm)
Boulders > 300 mm
Cobbles 75 to 300
Gravel 4.75 to 75
Sand 0.075 to 4.75
Silt < 0.075 mm
Clay < 0.075 mm
65.
slope
the change of elevation for a given horizontal distance of the Earth's surface,
often expressed as a percentage
66.
soil
G, S, M, C, O, and Pt are _____ symbols.
67.
soil classification
a system to describe the characteristics of a given soil in terms of its derivation
and physical makeup
68.
soil classification systems
USCS
AASHTO
OSHA
USDA
Modified Burmister classification system
69.
Soil consolidation can be accelerated with..
wick drains
70.
soil horizons
layers in a mature soil
71.
Soil liquefaction
Water-saturated soil loses most of it strength under the sudden influence.
72.
Soil percolation test does not provide
information about soil settlement
True
73.
Soil pores
The space between the soil particles
74.
Soil reports are a summary of subsurface
conditions of the job site only
True
75.
soil survey
a document classifying all the soils in a given geographic area, for the act of
examining the soils to prepare such a document
76.
soil survey report
a document prepared as a result of the scientific examination and classification of
a land area, used by farmers, planners, and soil conservationists to develop
land-use plans
77.
Some crawl space foundations are completely
sealed without any vents becuase
Cooler interior of air conditioned house in summer time may cause condensation
under the floor
78.
Subsurface Stresses
Know Math. 1 depth and 3 depths.
79.
texture
refers to the relative percentage of sand (largest), silt (midsized), and clay
(smallest) particles in the soil
coarse grained soil is mostly sand and is gritty to the touch
fine grained soil is mostly clay and feels silky to the touch, becoming slick or
sticky when wet
80.
To provide geotechnical engineers with a
general guidance about engineering properties
of the soils.
What is the purpose of classifying soils into groups with similar behavior?
81.
toughness index (TI)
TI = PI / FI
82.
Triaxial Test is a soil strength test
True
83.
Type A soil
cohesive soil with an unconfined compression strength of 1.5 top per square foot
or greater
84.
Type B soil
cohesive soils with an unconfined compression strength between 0.5 and 1.5 tsf, granular
cohesion less soils, unstable dry rock, type a soils that are exposed to a strength reduction
factor
85.
Type C soil
soils with an undefined compression strength of less than 05 tsf, very weak cohesive and
granular soils that are not classifies as Type a or b, submerged soil or if water is freely
seeping, any trench excavated to repair leaking pipes
86.
U
The ___-line indicates the upper bound for general soils.
87.
Uniformly graded
...
88.
Uniform Settlement
Where settling occurs at roughly the same rate throughout all parts.
89.
USCS
The ____ classification system was developed by Arthur Casagrande and is based on material
passing the 76mm (3in) sieve.
90.
USCS (Unified Soil Classification
System)
Classification system mainly used by geotechnical engineers.
91.
visual soil test
grain size, fissures, previously disturbed, layered, water, vibration
92.
Well Graded
wide range in particle size relatively straight GSD
93.
Well graded:
good representation of particle sizes over a wide range; gradation curve is generally smooth.
94.
Well graded
...
95.
What Does Young's Modulus
Measure?
The Stiffness of the Sample
96.
What is the unit of measurement
for soil strength
PSF
97.
Which foundation type is
especially popular in Northern
states
Full Basement
98.
Which one of the following does
not occur during the soil
consolidations
soil density decreases significantly
99.
Which one of the following
information CANNOT be found in
a soil report
Rebars for the footing
100.
Which one of the following is true
about undisturbed soil sample
Undisturbed sample produces better testing results for soil strength test
101.
Which statement correctly
describes the settlement features
of coarse grained soils
It is usually a good construction material because less settlement is expected
Soil Origin & Classification
Study online at quizlet.com/_gr2l5
1.
a
highly decomposed organic material
2.
angular and
subangular
blocky
common in B horizons; larger and
blocklike; subangular more rounded;
angular have sharper edges and are more
rectangular
3.
b
buried genetic horizon (major genetic
features that were developed before
burial)
4.
B horizon
dominated by obliteration of the original
rock structure
5.
brown soils are
rich with which
mineral
geothite
6.
c
concretions or nodules (cementation is
required)
7.
calcite
carbonate
8.
Chlorite
2:1:1 metal hydroxide between adjacent 2:1
9.
C horizon
excluding cemented and harder bedrock;
little effected by pedogenic processes;
lightly weathered? ( i.e. Entisols?)
10.
co
coprogenous earth (only used with limnic
(L) layers)
11.
columnar
structure
whitish caps on prisms; rounded tops
12.
combination
horizon
recognizable properties of two master
horizons; always capital letters; Ex. E/B,
B/C
13.
d
physical root restriction (noncemented
root restricting layers)
14.
definition of
mineral
a naturally occurring inorganic solid with
a definite chemical composition and an
ordered atomic arrangement
15.
di
diatomaceous earth (only used with
Limnic (L) layers)
16.
does pore space
increase or
decrease with
depth
decrease
17.
e
intermediate decompostion in the O
horizon
18.
E horizon
loss off silicate clay, iron, aluminum or
some combination of these
19.
f
frozen soil or water (layer that is contains
permanent ice)
20.
father of soil
science
Dokuchaev
21.
ferrihydrite
most common of Bhs of Spodosols
22.
ferritic
importance
to
managment
consideration
highest iron content
23.
ff
dry permafrost ( layer that is continually
colder than 0 degrees)
24.
g
strong gleying (iron has been reduced and
removed during soil formation; or saturation
with stagnant water has preserve it in a
reduced state; chroma of 2 or less; redox
concentrations; if no other change besides
gleying has taken place the horizon is
designated Cg)
25.
geothite
most common iron oxide in well drained
soils
26.
gibbsitic
importance
to
managment
consideration
highest aluminum content
27.
going from
red to yellow
what are the
hues
10R, 2.5YR, 5YR, 7.5YR, 10YR, 2.5Y, 5Y etc.
28.
granular
structure
1-5mm; crumb looking; caused by soil biota;
high porosity; high permeability
29.
gypsum
sulfate
30.
h
illuvial accumulation of organic matter
(accumulation of illuvial, amorphous,
dispersible complex of organic matter (i.e.
humus) and sesquioxides)
31.
halloysitic
1:1 associated with acid soils, volcanic parent
materials, can be tubular
32.
hematite
reddest iron oxide
33.
A horizon
show obliteration of the original rock
structure
34.
horneblende
inosilicate
35.
how are
micropores
commonly
formed
roots and biota
36.
how does xray
diffraction
work
the d-spacing can be calculated
corresponding to distance between
crystalline planes, and when certain minerals
are washed with potassium, glycerol and
heat they make certain arrangements which
can be inferred to identify the mineral
37.
how is soil
different from
sediment
soil develops from sediment
38.
hue
value/chroma
5YR 2/3
39.
i
slightly decomposed organic material (the
least decomposed that associates with an
O horizon)
40.
in value which
is white and
which is black
0 is black and 10 is pure white
is bulk density
high or low in a
soil horizon
high in organic
matter
low
j
accumulation of jarvosite ( product of
pyrite that has been exposed to an
oxidizing environment; hue of 2.5Y or
yellower (ex. 5Y) and a chroma of 6 or
more (i.e. brighter)
41.
42.
43.
44.
jj
k
evidence of cryoturbation (evidence
includes; irregular broken horizon
boundaries, sorted rock fragments, and
organic soil materials; often between active
layer and permafrost)
accumulation of secondary carbonates (
accumulation of visible pedogenic calcium
carbonate; carbonate filaments, coatings,
masses, nodules, disseminated carbonate,
or other forms)
45.
kaolinite
1:1 pseudo-hexagonal, very common in soils
46.
kaolinitic
importance to
managment
consideration
low activity clay
47.
kk
major accumulations of pedogenic calcium
carbonate
48.
left off on
page 36
...
49.
L horizon
Limnic horizons or layers that are both
organic and have mineral limnic materials;
only used in Histosols
50.
m
cementation or induration
(continuous or nearly continuous
cementation;
kkm or km - carbonates
qm - silica
sm - iron
yym - gypsum
kqm - carbonates and silica
zm - salts more soluble than
gypsum
51.
ma
marl (only used in Limnic (L)
layers)
52.
maghemite
common in tropical and
subtropical soils that have burned
53.
magnesic importance
to managment
consideration
low calcium, potential for heavy
metals
54.
magnetite
most magnetic
55.
mica
phyllosilicate
56.
M layers
human-manufactured
57.
Montmorillonite
2:1 high shrink swell
58.
muscovite
2:1 primary mineral with potassium
in interlayer
59.
n
accumulation of sodium
60.
o
residual accumulation of
sesquioxides
61.
p
tillage or other disturbance
(disturbance of a surface layer by
mechanical means, pasturing, or
similar uses)
62.
paleopedology
the study of buried soils
63.
pH dependent charge
at low pH does what to
anion exchange
capacity
increases it
64.
platy structure
consists of thin plate like peds that
are aligned parallel to the surface;
common in E horizons;
65.
prismatic structure
usually deeper in the profile;
blocks that are taller than they are
wide
66.
q
accumulation of secondary silica
67.
quartz
tektosilicate
68.
r
weather or soft bedrock (layers of
bedrock that are moderately or
less cemented
69.
red soils are rich
with which
mineral
hematite
70.
R layers
strongly cemented or indurated bedrock
71.
s
illuvial accumulation of sesquioxides and
organic matter (color value or chroma,
moist, 4 or more (i.e. whiter and brighter;
Bhs is color value and chroma, moist are
3 or less (dark)
85.
v
plinthite (indicates presence of iron-rich, humuspoor, reddish material; firm or very firm when
moist, less than strongly cemented; hardens
irreversibly when exposed to the atmosphere
and to repeated wetting and drying)
86.
w
development of color or structure (with little or
no apparent illuvial accumulation
87.
what does
chroma
refer to
the purity, strength, or grayness of the color
88.
what does
hue refer
to
the chromatic composition of the light, or
wavelength of the light, that emanates from the
object
89.
what does
the solum
consist of
the O, A, E, and B horizons
90.
what does
value refer
to
the darkness or lightness of the color; the
intensity of the color
91.
what
factor
most
influences
hue
minerology
92.
what is a
polypedon
the basic unit of soil classification; large enough
to exhibit all the soil characteristics considered
the in the descriptions and classification of
soils; contain pedons of all the same soil series
93.
what is a
soil
horizon
a layer formed by a pedogenic process that is
more of less parallel to the soil surface
sand and most of
the silt fraction
are composed of
what type of
minerals
primary
smectitic
importance to
managment
consideration
high shrink-swell
74.
soil
micromorphology
the study of the material and fabric of
the individual ped or parts therof
75.
soil morphology
all that can be seen and felt about a soil
76.
soil texture
the relative proportions of sand, silt, and
clay within the fine earth fraction
77.
a soil with equal
sand, silt, and
clay particles is
what texture
clay loam
78.
ss
presence of slickensides (result directly
from the swelling of clay minerals and
shear failure; wedge shaped peds and
surface cracks may also be present)
79.
t
accumulation of silicate clay
(translocated with the horizon or moved
in illuviation
94.
what is a
soil map
unit
an areal or cartographic representation of a
polypedon
80.
texture triangle
increasing clay
content
sand, loamy sand, sandy loam, sandy
clay loam, sandy clay, clay
95.
what is a
soil pedon
81.
texture triangle
increasing sand
content
silt, silt loam, sandy loam, loamy sand,
sand
the three dimensional equivalent of the soil
profile; it is the smallest soil body that still
retains all of the major variability of the soil; a
theoretical construct
96.
what is a
soil profile
a side view of the soil from the surface down
82.
texture triangle
silt content
clay, silty clay, silty clay loam, silt loam,
silt
97.
what is
porosity
the amount of void space in a soil
83.
transitional
horizon
dominated by properties of one horizon
but having subordinate properties of a
second; examples --AB, EB, BC
98.
low
84.
u
presence of human-manufactured
materials (artifacts of some type; wood,
glass, rubber, paper, cinder blocks,
medical waste, garbage, landfill waste)
what is the
bulk
density of
clayey
and silty
soils
72.
73.
99.
what is the name of the law used in x-ray diffraction
Bragg's law
100.
what is the regolith
the loose, unconsolidated material at the Earth's surface;
horizons A through R
101.
what kind of particle sizes are secondary minerals
clay-sized
102.
what soils feel gritty
sand
103.
what soils feel smooth
silt
104.
what soils form a ribbon
clayey
105.
what soils tend to be the most reactive
clayey soils
106.
what term refers to the pedon and the biota that exist within
and above it
tessera
107.
what two factors contribute to high soil permeabilities
pore size and pore interconnectedness
108.
which is more soluble, sodium chloride or gypsum
gypsum
109.
which two soil properties rely on proportins of oxalate
extractable iron and aluminum, among other characteristics?
spodic and andic soil properties
110.
white soils are rich with which minerals
salts or carbonates
111.
why are texture and coarse fragment content important
they affect the way water moves through and is retained in the
soil
112.
W layers
Water
113.
x
fragipan character (some part of the layer is physically root
restricted)
114.
y
accumulation of gypsum (dominated by soil particle or other
minerals other than gypsum
115.
yy
dominated by an accumulation of gypsum ( typically with
value of 7 - 9.5 (whitened) and chroma of 2 or less (dull)
116.
z
accumulation of salts more soluble than gypsum
Principles of Soil Mechanics
Study online at quizlet.com/_27dp5w
1.
An Aeolian soil is a soil which is
formed by:
transportation and
deposition of soil
particles by wind
a) deposition of soil particles
along or a base of a slope by
gravity
b) transportation and deposition
of soil particles by wind
c) erosion and weathering of
parent materials in place
d) deposition by flowing water in
a stream or river
2.
3.
Analysis of 1-D Permeameter
Systems:
the basis for weight- volume
calculations is the assumption that
the W(s), V(s) and G(s) of the soil
DOES NOT CHANGE from the
borrow area to the compacted fill.
5.
Clay minerals are formed by
chemical weathering of rock
minerals
True or False
False
True or False
6.
- Velocity head is
negligible
- All total head is lost in
the soil - no total head
lost in the open
permeameter tube,
reservoirs or very
coarse particles.
- Negative pore
pressures can exist
- Flow direction
determined by total
head gradient
- Method of head
component
determination:
- Start at flow
boundaries
- For heads in soil, first
determine elevation
head and
total head, calculate
pressure head
- Uniform loss of total
head in uniform soils
A clay soil has a liquid limit of 60%, a
plastic Limit of 20% and a natural, in situ
water content of 25%, The clay in the
natural, in situ state would likely:
have a stiff
consistency
a) be normally consolidated
b) have a high compressibility
c) have a stiff consistency
d) have a soft consistency
7.
Clay soils have plastic properties
because they contain a high percentage
of fines (particles smaller than the #200
sieve (0.075mm))
False
True or False
8.
A colluvial soil is a soil that was formed
by transportation of the soil particles
by gravity, such as down a slope to the
base of the slope
True
True or False
9.
Compacting a cohesive, clayey soil on
the dry side of optimum moisture
content contrasted with the wet side of
optimum will give the soil higher
potential for drying shrinkage.
False
True or False
10.
True
Compacting a cohesive, clayey soil on
the wet side of optimum moisture
content contrasted with the dry side of
optimum moisture content will give the
soil: (choose 2)
a) higher shear strength
b) higher potential for drying shrinkage
c) higher stiffness (i.e. higher slope of
the stress- strain curve)
d) a lower hydraulic conductivity
because the clay clods/aggregates can
be remolded.
True or False
4.
Clay minerals are formed by the
movement and crushing action of
glacier ice.
True
11.
Compaction of Fine Grained Cohesive
Soils examine the effect of water on:
- higher potential
for drying
shrinkage
- a lower
hydraulic
conductivity
because the clay
clods/aggregates
can be remolded.
-Soil structure
-Hydraulic
Conductivity
- volume change
behaviour
-Shear Strength
12.
Compaction rollers equipped with
Intelligent Compaction systems can
assess and quality control a higher
percentage of compacted earthworks
compared to using a nuclear density
gauge.
True
17.
Flow nets are useful for assessing:
- Seepage
losses from
reservoirs
- Pore pressures
on structures
(eg. uplift
pressures)
- Pore pressures
and seepage
velocities in
dams
- Critical points
with respect to
stability and
erosion of
water retaining
structures (e.g.
examine
hydraulic
gradients)
18.
For a clay soil compacted with a given
compactive effort, the maximum dry
density tends to decrease as plasticity
index of the clay soil decreases.
False
True and False
13.
14.
the design requirements of the
Compacted Clay Liner (CCL) for a
Municipal Solid Waste Landfill:
Determine the total volume of borrow
material in m^3 with a void ratio of 1.25
that is required to construct a
embankment of total volume 200,000
m^3 at a void ratio of 0.80.
- MINIMIZE
HYDRAULIC
CONDUCTIVITY
- Adequate
shear strength
- Shrink/swell
behaviour
- Deform
without cracking
and minimize
compressibility
- Resistance to
chemical attack
- Workability
and
constructability
- Availability of
materials
- Cost
True or False
19.
250,000 m^3
For a given soil, the modified Proctor
compaction curve will have a higher
optimum moisture content and a higher
maximum dry unit weight than the
standard Proctor compaction curve.
False
True or False
a) 312,500 m^3
b) 250,000 m^3
c) 160,000 m^3
d) 128,000 m^3
15.
Effective stress is less than the actual
contact stress between the soil particles
20.
True
For anisotropic hydraulic conductivity
conditions, the flow net is drawn in
transformed section with the horizontal
scale compressed relative to the vertical
scale because the horizontal hydraulic
conductivity is typically greater than the
vertical hydraulic conductivity.
True
True or False
16.
A flocculated clay structure has clay
mineral particles in a face- to- edge,
"cardhouse type" orientation and is
formed when there is net attraction
between the particles
True or False
True and False
True
21.
For clays, as specific surface area
decreases, the liquid limit increase.
False
True or False
22.
For downward, steady state seepage
through a saturated soil sample under a
hydraulic gradient of 1.0 the pressure
head is constant through the soil sample.
True and False
True
23.
For the equation k= 2.303 (aL/At )log(h(1)/h(2)) used
to analyze a falling head permeability test 't'
corresponds to elapsed time between total head
differences 'h(1)' and 'h(2)' is the cross- sectional
area of the standpipe.
False
Given a 1-m deep pond overlying a course gravel
layer, if the depth of the water in the pond
increases to 2-m, the effective stress within the
gravel will increase by 9.81 kN/m^3
33.
False
Hydraulic conductivity depends on the viscosity
and unit weight of the permeating fluid
True
34.
True of False
26.
Hydraulic conductivity does not depend on the
viscosity and unit weight of the permeating fluid.
False
If there is no change in total hydraulic head from
one point to another in a soil mass, then there is no
flow of water
True
35.
True or False
28.
In a dispersed structure clay mineral particles form
parallel, face- to- face orientation.
True
In a flow net for seepage through an embankment
dam, the change in pressure head is equal to the
change in elevation head along the top flow line.
36.
False
In a soil deposit, the horizontal hydraulic
conductivity is typically greater than the vertical
hydraulic conductivity
37.
True
In a stratified soil system ( with soil layers of
differing hydraulic conductivity values) with
horizontal flow parallel to the stratification, the
horizontal hydraulic gradient across each of the
layers is different.
True or False
False
One process that holds water molecules to a clay
mineral particle surface is the attraction of dipolar
water to the negatively charged clay mineral
particle surface
True
One process that holds water molecules to a clay
mineral particle surface is the attraction of dipolar
water to the negatively charged clay mineral
particle
True
The pressure in capillary water above the water is
equal to atmospheric pressure.
False
True or False
38.
True or False
31.
Negative pore cannot occur in a 1-D permeameter
system with steady state seepage because water
will be in a state of compression with steady state
seepage.
True or False
True or False
30.
46.4%
True or False
True or False
29.
A moist soil sample weighing 0.02kN has a moisture
content of 33.0%. If 0.002kN of water are added to
the sample, the moisture content of the sample
will be:
True or False
True and False
27.
True
a) 46.4%
b) 43.0%
c) 33.1%
d) Need a value of G(s) of the soil to solve this
problem.
True or False
25.
It is the total head that determines flow of water in
soils. No change in total head from one point to
another in a soil, no flow of water.
True or False
True and False
24.
32.
False
the relationship between zero air voids dry unit
weigh and moisture content is linear on a graph of
dry unit weight versus moisture content
False
True or False
39.
The relationship between zero air voids dry unit
weight and moisture content depends on the
compactive effort applied to the soil.
True or False
False
40.
A residual soil is a soil
the was formed by
transportation of the soil
particles by gravity, such
as down a slope to the
base for the slope.
False
45.
Seepage velocity is:
a) lower than discharge
velocity
b) determined by
dividing the discharge
velocity (numerator) by
the void ratio of the soil
(denominator)
c) the product of the
hydraulic conductivity
times the hydraulic
gradient
d) determined by
dividing the discharge
velocity (numerator) by
the porosity of the soil
(denominator)
42.
Seepage velocity is
determined by
multiplying the discharge
velocity by porosity of
the soil
46.
determined by dividing the
discharge velocity (numerator)
by the porosity of the soil
(denominator)
Soil with a G(s) of 2.71 and a water content
16% is compacted to produce a cylindrical
sample of volume 8.619e-5 m^3. After
compaction 6% of the total volume of the
sample is air. The weight of the soil solids in
kN that is required to form this sample is:
Slug Test
False
are used to determine the
hydraulic conductivity of the
formation in the immediate
vicinity of a monitoring well
screened interval.
- it involves injecting or
withdrawing a known volume of
water from a well and
monitoring formation's response
by measuring the rate at which
the water level returns to
equilibrium.
44.
Soil compaction is a
function of:
1.50e-3 kN
a) 26.59 kN
b) 1.50e-3 kN
c) 2.16e-3 kN
d) 1.75e-3 kN
47.
The Three major classifications that is
Identified through the USCS are:
Coursegrained
Soils
Finegrained
Soils
Highly
organic
soils
48.
To improve the engineering properties of
soil through compaction:
- Reduce
settlements
- Increases
strength and
bearing
capacity
- Reduce
permeability
(e.g. dams,
levees,
landfill
liners)
49.
Water will rise higher above the water table
in a clay rather than a sand because the size
of the interconnected pore spaces of a clay
are smaller that those of a sand
True
True or False
43.
True
True or False
True or False
41.
A soil has water content of 20% degree of
saturation of 90% and specific gravity of soil
solids of 2.70. the porosity of this soil is 37.5%
1) Water content
2) Compactive effort
3) Soil type
True or False
50.
Weight- Volume Relationships:
Soils can be a 2 phase, 3 phase, 4 phase medium:
2 phase: dry soil or saturated soil
3 phase: unsaturated soils- soil solids, water and air
4 phase: soil solids, liquid water, air ice (frozen soil) or soil
solids, water, air, and contaminant (e.g. gasoline), soil: tire
shred mixture
51.
What is the water content percentage of dry soil?
0%
52.
What is the water content percentage of saturated soil?
100%
53.
Why are soil mechanics and geotechnical engineering an
important discipline of civil engineering?
Because every other civil engineering discipline, in some
important way, depends on a knowledge and application of
soil mechanics and geotechnical engineering.
54.
You cannot have a flow line in parallel to an equipotential line
because total head doesn't change along the equipotential line.
(flow lines must always be perpendicular)
True
True or False
10-7-14 Soil True Or False Questions
Study online at quizlet.com/_u9bvv
1.
Available water capacity is the amount of water
stored in maropores.
False
25.
Slope is the vertical rise or fall of land in a
measured horizontal distance and is measured in %.
True
2.
The "B" horizon is also known as the top soil layer.
False
26.
True
3.
A clayey soil can contain various amounts of rock
fragments.
True
Soil aeration is the exchange of air in the soil with
air in the atmosphere.
27.
True
Clay is sticky and plastic when moist and cannot be
seen under and ordinary microscope.
True
Soil is a natural, three-dimensional material at the
earth's surface, capable of plant support
28.
True
A flood plane is the higher part of the landscape
above the terraces and hill slopes.
False
The soil is commonly used as a secondary or
tertiary treatment of effluent.
29.
True
Glacial lake deposits are primarily clay and silt
sized sediments.
True
Soils formed in lacustrine sediment are considered
to be on uplands.
30.
True
Gray and black mottling indicates oxidation or the
presence of oxygen.
False
Soil slippage can create irregular soil surfaces with
hummocks and depressions.
31.
True
The installation of subsurface drainage will
generally correct limitations caused by Seasonally
high water tables.
True
Soil slippage generally occurs on slopes greater
than 12%.
32.
Soil structure is determined by the amount of silt,
sand and clay.
False
9.
Layers of gravel or sand will prevent root growth
and are considered restrictive layers.
True
33.
Soils with shallow depths to the water table are said
to have a low water table.
False
10.
A loamy texture can have equal proportions of
sand, silt, and clay.
True
34.
Subsidence is the loss of volume that occurs in
clayey soils upon drying.
False
11.
Many roots can be found in the Fragipan.
False
35.
False
12.
Mottling in the subsoil indicates the presence of a
fluctuation water table.
True
A well developed subsoil is always present in the
soils located in flood planes.
36.
True
13.
Mottling is a combination of various shades of gray
and brown often patterned as splotches.
True
Well drained or excessively drained soils are
uniformly bright colored.
14.
Muck soils have extremely high water holding
capacity.
True
15.
Permeablility is the ability of the soil to hold water.
False
16.
The presence of sand and/or gravel in the
substratum of soils always means it is a terrace
landform.
False
17.
The principal forms of soil structure include platy,
prismatic, columnar, blocky, and granular.
True
18.
A rise or fall of 4 feet in 50 feet is equal to a 4%
slope.
False
19.
Sandy soil texture is described as usually smooth to
slightly gritty.
False
20.
Sheet erosion in Ohio is more serious than gulley
erosion.
True
21.
The shrinking of soil when dry, and swelling when
wet is known as frost heave.
False
22.
Shrink swell activity is greatest influenced by
organic material content
Falsé
23.
Silt is the smallest soil particle
False
24.
Six feet of rise and fall in 75 feet of horizontal
distance is a 6% slope.
False
4.
5.
6.
7.
8.
Soils Final
Study online at quizlet.com/_47375d
1.
0m is a measure of _____.
Amount of
water mass
related to soil
mass
2.
The action of water moving into the soil is
called _____.
Infiltration
3.
The action of water moving through the soil
is called _____.
Percolation
4.
Alluvial fans are form by _____.
Flowing water
5.
The amount of different sizes of mineral
particles in a soil defines the soil
Texture
6.
The attraction of water to other water
molecules is called ______.
Cohesion
7.
The attraction of water to solid surfaces is
called _____.
Adhesion
8.
At which of the following soil moisture
potentials (expressed as kPa) is the soils
water held most tightly?
-3100
9.
Clays are not _____.
Very tiny rock
minerals
10.
CO2 is important in soil air because plant
roots need CO2 to photosynthesize.
False
11.
Colluvium is a material that has been
transported by water.
False
12.
Compared to silt, clay-sized soil particles
are characterized by ______.
A greater
attraction
13.
Decomposition of minerals is mostly
chemical in which climate?
Warm and
wet
14.
An E horizon is a zone in which materials
such as silicate clays have been
accumulated
False
15.
Eolian material has been deposited by _____.
Wind
16.
Epipedons are diagnostic subsurface
horizons that are one of the primary means
of classifying soils in the United States.
False
For any soil in which it is present, the C
horizon is the parent material for the B
horizon
True
For which substances would the particle
density equal the bulk density?
a quartz
pebble
17.
18.
19.
Glacial till is a term used to describe
parent materials that:
Contain a
heterogeneous
mixture of minerals
debris dropped by
receding glaciers.
20.
Granite is an example of a _____.
igneous rock
21.
The greater inward attraction of
water molecules to themselves less
than the attraction to other
molecules creates phenomenon
known as ______.
Surface tension
22.
The hydrogen end of a water
molecule is attracted to positively
charged cations such as Na+ and
Ca2+
False
23.
If you wanted to find a soil where
physical weathering dominated over
chemical breakdown you would be
most apt to find it in _____.
A desert region of
Arizona
24.
Igneous rocks can be best
characterized as:
Rocks formed when
molten magma
solidifies
25.
In a given soil, of the following
horizons with the highest organic
matter content is generally the _____
horizon.
A
26.
Increasing clay content in soil with
high humus content will typically
_______.
Increase bulk
density
27.
Increasing the organic matter
content of a soil is likely to ______.
Increase the soils
water infiltration
28.
In glacial outwash, the fine material is
deposited close to the running water
and the coarse material is deposited
further away.
False
29.
In many soil profiles, the subsoil is
high in clay but is also quite
permeable to percolate water. Why?
Prismatic structure
may be well
developed
30.
In which of the following horizons has
the process of illuviation occurred?
B horizon
31.
The layers of contrasting material
found when one dogs a hole in the
ground are called
Horizons
32.
Light colored surface soils are likely
to be warmer than dark-colored
surface soils if soil moisture and other
conditions are the same.
False
33.
The lithosphere is made up of _____.
Rock and soil
34.
A low energy bond between a hydrogen
atom of one molecule of water and the
oxygen atom in another is called ______.
Hydrogen
bond
35.
The matric potential is due to the attraction of
water molecules to soil solid surfaces.
True
36.
Matric potential is the ability of water to _____.
Do work
when
adsorbed
to a
particle
37.
The mineral particles in soil consist of sand,
silt and clay.
True
38.
The mineral portion of soil often constitutes
about _____ of the total soil volume.
50%
39.
Most of the different nutrients essential for
growth are supplied to plants directly from
Soil
solution
40.
Of the options below, which is the most
important correct sequence of horizons?
OAEB
41.
OM plays an important role in stabilizing
surface soil aggregates.
True
42.
Osmotic and matric potentials are commonly
negative because the soil water has a lower
energy level than that of pure water
True
43.
Osmotic potential is the ability of water to do
work _____.
With
chemicals
in solution
44.
A pedon is a 3-dimensional field unit
occupying about 1000 square meters (1 ha) of
land area.
False
45.
The percentages of which soil components
represent the minimum information necessary
in order to determine the textural class of
soil?
Silt and
sand
46.
The percent of total pore space in soil can be
calculated if only the particle density and the
organic matter content are known.
False
47.
The Pp (bulk density) of a soil with a Pp (bulk
density) of 2.65 g/cm^3 and Ep (porosity) of
50% is _____.
1.3
48.
Practices that add organic matter and reduce
tillage can be expected to most significantly
increase the ______ in a soil.
Total
porosity
49.
The property of cohesion in water stems from
the attraction of water molecules for soil
solids.
False
50.
Sandstones are good examples of
metamorphic rocks.
False
51.
Soil air is similar to atmospheric air but
has higher percentages of _____.
CO2
52.
Soil are usually has a higher CO2 content
than the air in the atmosphere.
True
53.
Soil colors that are gleying indicate
which condition?
Long durations
of inadequate
aeration
54.
Soil occupies the ______ part of regolith.
Upper
55.
A soil pedon ____________.
A three
dimensional unit
that embodies
the primary
characteristics
of an individual
soil
56.
Soils developed from wind-blown parent
materials such as loses are generally of
little agricultural value.
False
57.
Soils high in organic matter commonly
have more plant available water than
comparable soils with lower organic
matter levels. This is most likely due to
what characteristics of the high O.M.
soils.
Higher field
capacity
58.
Soils in this order are commonly sandy
in texture, quite acidic and develop
primarily under coniferous trees in cool
cold climates
Spodosols
59.
Soils with low percentage of porosity
have ______.
High bulk
density
60.
A soil with an even balance of all
particle size classes would best describe
as a _____.
Loam
61.
A sticky, putty like feel indicates a high
percentage of which soil separate?
Clay
62.
Texture describes the percent of _______
particles in a soil
Sizes
63.
The topmost horizon in most humid
region forest soils is the A horizon
False
64.
"Topsoil" is generally equivalent to which
soil horizon?
A
65.
Two soil samples, A & B, at different soil
moisture levels are places in contact
with each other. Water will more likely
move from soil A to soil B if their water
potentials, expressed in kPa are
A = -30 B = -40
(high to low)
66.
Unsaturated water flow _____.
Is stimulated by
the osmotic
potential
67.
Water is a _______ molecule.
Polar
68.
Weathering of rocks usually is most intense in the center of a rock fragment, and gradually decreases toward the
outside.
False
69.
Which of the following categories of Soil Taxonomy is the most specific of soil properties?
Series
70.
Which of the following experessions in kPa is most apt to characterize the gravitational water potential of a surface
soil?
-30
71.
Which of the following is considered to be a plant macronutrient?
N
72.
Which of the following minerals is most resistant to weathering?
Quartz
73.
Which type of soil structure is typically found in surface soil (A horizons)?
Granular
2021/1/10
Sieve Analysis - Soil Mechanics Questions and Answers - Sanfoundry


Soil Mechanics Questions and Answers – Sieve
Analysis
« Prev
Next »
This set of Soil Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Sieve
Analysis”.
1. Sieve analysis is meant for______
a) coarse-grained soils
b) ne-grained soils
c) coarse-grained gravel
d) silt
View Answer
Answer: a
Explanation: Sieve analysis is rst stage of particle size analysis which is meant for coarsegrained soils only, while the second stage is the sedimentation analysis which is performed for
ne-grained soils.
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2. In Indian Standard (IS : 460-11962) the sieve sizes are given by_____
a) number of openings
b) number of openings per inch
c) size of aperture in mm
d) size of aperture in cm
View Answer
Answer: c
Explanation: In the BS and ASTM standards, the sieve sizes are given in terms of number of
openings per inch. In Indian Standard, the sieves are designed by the size of aperture in mm.
3. The portion retained on______ IS sieve is termed as gravel fraction.
a) 4.75mm
b) 2mm
c) 425micron
d) 75micron
View Answer
Answer: a
Explanation: The portion retained on 4.75mm sieve is kept for coarse analysis, hence termed
as gravel fraction. While the portion passing through 4.75mm sieve is subjected to ne sieve
analysis.
4. The receiver at the bottom of the assembly in sieve shaking machine is________
a) 4.75mm sieve
b) 425micron
c) pan
d) 75micron
View Answer

Answer: c
Explanation: A pan is kept at the bottom of the whole assembly to collect the nest particles of
the soil sample that is used in the experiment.
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Sieve Analysis - Soil Mechanics Questions and Answers - Sanfoundry
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5. Sieving is performed by arranging the various sieves one over the other in the order of their
mech openings.
a) True
b) False
View Answer
Answer: a
Explanation: The largest aperture sieve being kept at the top and the smallest aperture sieve is
at the bottom of the assembly lled on a sieve shaking machine.
6. ______ minutes of shaking is done for soil with small particles.
a) 2
b) 10
c) 15
d) 60
View Answer
Answer: b
Explanation: The amount of shaking depends upon the shape and number of particles. At least
10 minutes of shaking is desirable for soil particles.
7. The percentage of soil retained on each sieve is calculated on the basis of ______
a) total mass
b) total weight
c) volume of sample
d) density of soil

View Answer
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8. The soil portion passing through 4.75 mm sieve is washed for further sieve analysis.
a) True
b) False
View Answer
Answer: a
Explanation: It is advisable to wash the soil portion passing through 4.75 mm sieve so that silt
and cay particles sticking to the sand particles may be dislodged.
9. ______ is used for washing the soil portion passing through 4.75 mm sieve.
a) distilled water
b) 2g of sodium hexametaphosphate per litre of water
c) 10% of brine solution
d) kerosene
View Answer
Answer: b
Explanation: Sodium hexametaphosphate acts as a dispersing agent that prevents occulation
or the combining of suspended matter into aggregates that settle due to gravity.
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To practice all areas of Soil Mechanics, here is complete set of 1000+ Multiple Choice Questions
and Answers.
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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is
Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN
Architect and is passionate about competency developments in these areas.
He lives in Bangalore and delivers focused training sessions to IT
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Textural Classification - Geotechnical Engineering Questions and Answers - Sanfoundry


Geotechnical Engineering Questions and
Answers – Soils – Textural Classi cation
« Prev
Next »
This set of Geotechnical Engineering Multiple Choice Questions & Answers (MCQs) focuses on
“Soils – Textural Classi cation”.
1. Soil classi cation based on the particle size distribution is _____________
a) Uni ed soil classi cation
b) IS classi cation
c) Particle size classi cation
d) Textural classi cation
View Answer
Answer: d
Explanation: Soil classi cation of composite soils exclusively based on the particle size
distribution is known as textural classi cation.
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Textural Classification - Geotechnical Engineering Questions and Answers - Sanfoundry
2. The best known classi cation system in textural classi cation is __________
a) M.I.T. classi cation system
b) Triangular classi cation of U.S. public road administration
c) Indian classi cation system
d) International classi cation
View Answer
Answer: b
Explanation: Triangular classi cation of U.S. public road administration is a commonly used
system for textural classi cation.
3. Textural classi cation is most suitable for ____________
a) Clay soil
b) Wet soil
c) Coarse grained soil
d) Soil with moist
View Answer
Answer: c
Explanation: Since the textural classi cation is based on the percentages of sand, silt, and clay
size making up the soil. Such a classi cation is more suitable for describing coarse-grained soil.
4. To use textural classi cation chart ___________ lines must be drawn.
a) Parallel to the three sides of the triangle
b) Parallel to the only one side of the triangle
c) Adjacent to the three sides of the triangle
d) Adjacent to the one sides of the triangle
View Answer
Answer: a
Explanation: To use the textural classi cation chart, for a given percentage of three

constituents forming a soil, lines are drawn parallel to three sides of the equilateral triangle.
5. The type of triangle, used in textural classi cation of soil is _____________
a) Right angled triangle
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Textural Classification - Geotechnical Engineering Questions and Answers - Sanfoundry
b) Equilateral triangle
c) Perpendicular triangle
d) None of the mentioned
View Answer
Answer: b
Explanation: A triangle, having equal length of sides (i.e. Equilateral triangle) is used in textural
classi cation chart.
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6. Public road administration (PRA) system is based on _____________
a) Particle-size composition and Plasticity characteristics
b) Particle size distribution
c) All of the mentioned
d) None of the mentioned
View Answer
Answer: a
Explanation: HRB classi cation system, also known as public road administration (PRA) is
based on both the particle-size composition and plasticity characteristics.
7. Highway research board (HRB) classi cation system is also known as__________
a) Indian classi cation system
b) Public road administration (PRA) system
c) International classi cation system
d) M.I.T. classi cation system

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Textural Classification - Geotechnical Engineering Questions and Answers - Sanfoundry
Answer: b
Explanation: Highway research board classi cation system is also known as public road
administration (PRA) system.
8. Based on HRB classi cation system, the soil are divided in to ___________
a) 2 primary groups
b) 6 primary groups
c) 7 primary groups
d) 6 primary groups
View Answer
Answer: c
Explanation: Based on HRB system, the soil is divided into 7 primary groups, designated as A-1,
A-2…A-7.
9. The performance of the soil, when used for pavement construction is found out by using
_____________
a) Quality test
b) Group index
c) Material test
d) None of the mentioned
View Answer
Answer: b
Explanation: As group index is a mean of rating the value of soil as a sub-grade material. It can
be used for nding the performance and quality of the soil.
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Textural Classification - Geotechnical Engineering Questions and Answers - Sanfoundry
10. The group index of a soil depends on ____________
a) Liquid limit
b) Plastic limit
c) All of the mentioned
d) None of the mentioned
View Answer
Answer: a
Explanation: Group index of soil usually varies by
i. Liquid limit
ii. Plastic limit
iii. Amount of material passing through the 75-micron IS sieve.
11. Group index is de ned by which of the equation?
a) GI=0.2b+0.005ac+0.01bd
b) GI=0.2a+0.005bd+0.001ac
c) GI=0.2a+0.005ac+0.001bd
d) GI=0.2a+0.5ac+0.001bd
View Answer
Answer: c
Explanation: Group index (GI) is given by the following equation
GI = 0.2a+0.005ac+0.01bd.
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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is
Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN
Architect and is passionate about competency developments in these areas.
He lives in Bangalore and delivers focused training sessions to IT
professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux
Networking, Linux Storage, Advanced C Programming, SAN Storage
Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber
Channel. Stay connected with him @ LinkedIn
Subscribe Sanfoundry Newsletter and Posts
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