‫الواجبات‬
Homework No.1
1)
Soil is produced by weathering of rock. Weathering includes two
distinctive types of processes called: (a) Physical Weathering and (b) Chemical
Weathering.
a) How would you differentiate between the two types of processes?
b) Name and describe the processes that contribute to physical
weathering.
c) Name and describe the processes that contribute to chemical
weathering.
d) How would you use the above information to explain the difference in
the mineralogy of lunar soils versus terrestrial soils?
2. (a) How does rainfall and temperature influence rate of soil weathering?
Give examples of soil minerals found in cool, dry climates versus warm,
humid climates. Also compare the mineralogy of soil found in each of
these two extreme environments with those found in rocks.
(b) What role does drainage play in determining the rate and the products of
weathering?
3. What are residual soils and how do they differ from transported soils?
4. What are Loessal deposits? How are they formed?
Homework No.2
A large block specimen of moist soil from a landfill liner weighs 330 pounds and
has a volume of 3.00 ft3. Its moisture content is 25.0% and the specific
gravity of solids is 2.70. Compute the void ratio, porosity, degree of
saturation, and unit weight (both total and dry) of this soil
An undisturbed Shelby tube soil sample is 60 mm in diameter and 152 mm long.
It has a mass of 816 g. After finding the mass of the entire sample, a small
portion was removed and a moisture content test was performed on it. The results
of this test on the sub-sample were:



Mass of can = 22.01 g
Mass of can + moist soil = 124.97 g
Mass of can + dry soil = 112.72 g
Assuming a Gs of 2.70, compute , d, e, and S
Homework No.3
Find the USCS Classification (Group Symbol and Group Name) for:
a. Soil A; inorganic soil
b. Soil B; inorganic soil
c. Soil C; contains organic matter
The plasticity properties of the 3 soils are as follows:
Soil A
Soil B
Soil C
Liquid Limit
(LL)
42
23
73 (before oven drying)
51 (after oven drying)
Plastic Limit
(PL)
30
17
25
Find the AASHTO Classification (Group Classification and Group Index) for:
a. Soil A
b. Soil B
c. Soil C
The following data were obtained from a sieve analysis test performed on a soil
sample using 450g of coarse-grained soil sample. Classify the soil using
Unified and AASHTO soil classifications systems. Use handouts on soil
classification. Atterberg limit tests show that LL = 52 and PI = 28.
Sieve Size (No.)
4
10
20
40
60
100
200
Percent Retained
00.0
4.50
10.50
24.50
18.90
21.20
13.50
Homework4
Following are the results of a mechanical sieve analysis:
Sieve No.
4
10
20
40
Mass of Soil Retained (g)
28
42
48
128
60
100
200
Pan
221
86
40
24
a) Determine the percent finer than each sieve and plot a grain-size distribution
curve.
b) Determine D10, D30, and D60 from the grain-size distribution curve.
Determine the percent gravel, percent sand, and percent fines for soils A, B, and C in
the attached Figures. Calculate Cu and Cc for each soil. Classify each soil according
to their USCS, AASHTO, and USDA classifications.
For a given sandy soil, emax = 0.86 and emin = 0.43. What is the void ratio at a relative
density of 56%?
Following are the results from the liquid and plastic limit tests for a soil:
Number of Blows (N)
14
16
20
28
Moisture Content (%)
38.4
36.5
33.1
27.0
Water content at which 1/8” threads of soil are rolled to the point they just begin to
crumble: 12.2%
a)
Draw the flow curve and obtain the liquid limit.
b)
What is the plasticity index of the soil?