Name of the Faculty with Designation: Mr. P. SABARISHKUMAR
Year/Branch/Section
: III Year / V Semester
Course Title & Code
: CE6502 & FOUNDATION ENGINEERING
Two Marks and 16 marks questions
UNIT – I
SITE INVESTIGATION AND SELECTION OF FOUNDATION
Scope and objectives – Methods of exploration – auguring and boring – Wash
boring and rotary drilling – Depth of boring – Spacing of bore hole – Sampling
techniques – Representative and undisturbed sampling – methods - Split spoon
sampler, Thin wall sampler, Stationery piston sampler – Penetration tests (SPT
and SCPT) - Bore log report – Data interpretation - strength parameters and
Liquefaction potential - Selection of foundation based on soil condition.
Part A (2 marks for each question)
1. What are the methods of site exploration?
2. What are the methods of boring?
3. What do you understand about disturbed and undisturbed soil samples?
4. What are the information’s extracted from the site investigation?
5. What are the purposes of site investigation?
6. What are the factors that affect the sample disturbance?
7. Define area ratio of soil sampler.
8. Define recovery ratio of soil sampler.
9. What is meant by site reconnaissance?
10. What is mean by refusal in SPT?
11. What are the engineering properties of disturbed soil sample?
12. What are the corrections to be observed in SPT?
13. What is meant by bore hole log report?
14. Define site investigation.
15. What are the primary objectives of soil exploration?
16. Define boring.
17. What is significant depth?
1
18. Define undisturbed samples.
19. Define sampling.
20. What are the types of samplers?
21. List out the types of penetration tests.
22. What are the stages of site investigation?
Part B (16 marks for each question)
1. Explain in detail about the methods of site exploration with neat sketch.(16)
2. Explain any two types of samplers with its application.
(16)
3. Explain standard penetration test and static cone penetration test with its
significance.
(16)
4. Explain the Dynamic cone penetration test with its significance.
(16)
5. Explain the methods of boring and drilling with neat sketch.
(16)
6. Write short notes on
I. Spacing of boring
II. Depth of boring
III.Bore hole log report
(5)
(5)
(6)
7. Explain two categories of geophysical methods.
(16)
8. Discuss the arrangements and operations of stationary piston sampler.
(16)
9. Explain the electrical Resistivity method in detail.
(16)
10. Draw a neat sketch of the set-up for wash boring and discuss the procedure of
soil exploration through wash boring.
(16)
11. Explain short notes on sounding and penetration test.
2
(16)
UNIT II
SHALLOW FOUNDATION
Introduction – Location and depth of foundation – Codal provisions – bearing
capacity of shallow foundation on homogeneous deposits – Terzaghi‟s formula and
BIS formula – factors affecting bearing capacity – problems – Bearing capacity
from in-situ tests (SPT, SCPT and plate load)Allowable bearing pressure – Seismic
considerations in bearing capacity evaluation. Determination of Settlement of
foundations on granular and clay deposits – Total and differential settlement –
Allowable settlements – Codal provision – Methods of minimizing total and
differential settlements.
Part A (2 marks for each question)
1.
2.
3.
4.
5.
6.
7.
8.
Define Footing.
What is Shallow foundation?
Define Foundation.
What is the minimum depth of foundation?
Define Bearing capacity of the soil.
Define Ultimate bearing capacity of the soil.
Define Net Ultimate bearing capacity.
Write any two assumptions made in the derivation of Terzaghi’s bearing
capacity theory.
9. What are the factors that affect bearing capacity?
10. Define net safe bearing capacity.
11. What is meant by safe bearing capacity?
12. Define allowable bearing capacity or pressure.
13. What are the types of shear failure occurs under footing?
14. What are the points observed in a general shear failure?
15. What are the conditions under which the punching shear failure occurs?
16. Write short note on Depth of foundation.
17. Define deep foundation.
18. What is meant by penetration resistance?
19. Write formula for Dilatancy correction.
20. Write down the limitations of the plate load test.
Part B (16 marks for each question)
1. What is shallow foundation? Explain its types with neat sketch.
(16)
2. What is settlement? What are the different types of settlement and explain
briefly.
(16)
3
3. Explain the test to be conducted to find out the bearing capacity.
(16)
4. Explain in detail about the factors that affecting the bearing capacity of soil for
foundation.
(16)
5. A Strip footing of width 3m is founded at a depth of 2m below the ground surface
in a (c-¢) soil having a cohesion c =30 kN/m2 and angle of shearing resistance ¢=
35o.The water table is at a depth of 5m below ground level. The moist weight of
soil above the water table is 17.25 kN/m2. Use the general shear failure theory of
Terzaghi.
For ¢ = 35o, Nc = 57.8, Nq = 41.4 and N‫ = ע‬42.4 Determine
(i) the safe bearing capacity of the soil
(6)
(ii) The net safe bearing capacity of soil
(5)
(iii) The ultimate bearing pressure for a FOS = 3.
(5)
6. Determine the depth at which a circular footing of 2m diameter be placed to
provide a FOS of 3, if it has to carry a safe load of 1600 kN. The soil is having
angle of internal friction Ф = 30o. The unit weight of the soil is 21 kN/m3.Use
Terazghi’s analysis.(Nq=22andN‫=ע‬20)
(16)
7. A strip footing 2m wide carries a load intensity of 400 kN/m 2 at a depth of 1.2m
in sand. The saturated unit weight of sand is 19.5 kN/m 3 and unit weight above
water table is 17kN/m3 .The shear strength parameters are C= 0 and ¢ = 35 o.
Determine the FOS with respect to shear failure for the following cases of
location of WT. (Nq = 41.4and N‫ = ע‬42.4)
i. Water Table is 4m below GL
(8)
ii.WaterTable is 1.2m below GL
(8)
8. Explain different types of shear failures of soil with neat sketch.
9. Discuss briefly on selection of foundation based on soil condition.
(16)
(16)
10. Compute the safe bearing capacity of a square footing 1.5 m x 1.5 m located at
a depth of 1 m below the ground level in a soil of average density 20 kN/m 3, ¢ =
20°, Nc = 17.7, Nq = 7.4 and N‫ = ע‬5. Assume a suitable factor of safety and that
the water table is very deep. Also compute the reduction in safe bearing capacity
of the footing if the water table rises to the ground level.
(16)
11.Determine the depth at which a circular footing of 2m diameter be founded to
provide a FOS of 3, if it has to carry a safe load of 1600KN. The foundation soil
has C= 10KN/m2, φ =30ₒ and unit weight = 18KN/m3.UseTerzahi’s analysis. (16)
4
12.A square footing 2.5m X 2.5m is built in a homogeneous bed of sand of unit
weight 20KN/m3 and having an angle of shearing resistance of 36 ₒ.The depth of
the base of footing is 1.5m below the ground surface. Calculate the safeload that
can be carried by a footing with a FOS of 3 against complete shear failure. Use
Terzahi’s analysis.
(16)
5
UNIT III
FOOTINGS AND RAFTS
Types of footings – Contact pressure distribution: Isolated footing – Combined
footings – Types and proportioning – Mat foundation – Types and applications –
Proportioning – Floating foundation – Seismic force consideration – Codal
Provision.
Part A (2 marks for each question)
1. Define footing.
2. Under what circumstances, a strap footing is adopted?
3. Define Mat foundation.
4. Under what circumstances, the mat foundation is used?
5. Define spread footing.
6. What are types of foundation?
7. What are the footings comes under deep foundation?
8. Define floating foundation.
9. What is mean by proportioning of footing?
10. What are the assumptions made in combined footing?
11. List down the types of penetration tests.
12. What are the corrections to be applied in observed N values?
13. Classify the Shallow foundations.
14. Write any three assumptions made in Terazghi’s bearing capacity theory.
15. Define contact pressure below footings.
16. What are the different types of shear failure?
17. Define settlement.
18. What are types of settlement of foundation?
19. What is meant by allowable settlement?
20. What is meant by isobar?
Part B (16 marks for each question)
1. What are the different types of raft foundations? Explain in detail with neat
sketch.
(16)
2. Explain the design procedure of isolated footing.
(16)
3. Briefly explain the structural design of spread footing.
(16)
4. Briefly explain how proportioning and structural design of trapezoidal combined
footing is done with diagram.
(16)
6
5. List the types of foundations along with their uses.
(16)
6. Write down the design procedure for rectangular combined footing.
(16)
7. Explain contact pressure and settlement below footings with neat sketch.
(16)
8. List and discuss the methods of minimizing settlement.
(16)
9. Design a rectangular combined footing for uniform pressure under dead load plus
reduced live load, the following data:
Allowable soil pressure: 150 KN/m2 for DL + reduced LL, 225 KN/m2 for DL + LL
Column loads:
Column A
Column B
DL
540 KN
690 KN
LL
400 KN
810 KN
c/c distance of columns = 5.4m.
Projection of footing beyond column A = 0.5m
(16)
10. A trapezoidal footing to be provided to support two square columns of 30cm and
50cm sides respectively columns are 6m apart and the safe bearing capacity of soil
400KN/m2.the bigger column carries 5000KN.the smaller column 3000 KN. Design
suitable size of footing, so that it does not extend beyond the faces the column.
(16)
7
UNIT IV
PILE FOUNDATION
Types of piles and their function – Factors influencing the selection of pile –
Carrying capacity of single pile in granular and cohesive soil – static
formula – dynamic formulae (Engineering news and Hileys) – Capacity from
insitu tests (SPT and SCPT) – Negative skin friction – uplift capacity- Group
capacity by different methods (Feld‟s rule, Converse – Labarra formula and
block failure criterion) – Settlement of pile groups – Interpretation of pile
load test (routine test only) – Under reamed piles – Capacity under
compression and uplift.
Part A (2 marks for each question)
1. Define Pile.
2. How is the type of pile foundation selected?
3. What is mean by group settlement ratio?
4. What are the factors to be considered while selecting the type of pile?
5. What are the types of hammer?
6. Define pile driver.
7. What are the methods to determine the load carrying capacity of a pile?
8. What are the two types of dynamic formulae?
9. What is meant by single-under reamed pile?
10. Write down the static formulae.
11. Define modulus of sub grade reaction.
12. Write down the types of pile load tests.
13. Write short notes on Group action of piles.
14. What is meant by tension piles?
15. Write any three necessity of pile foundation.
16. Classify the piles based on the mode of transfer of loads.
17. List out the type of pile based on material used.
18. What is meant by pier?
19. Write short notes on the settlements of pile groups.
20. What is meant by laterally loaded piles?
Part B (16 marks for each question)
1. Explain the method of determining the load carrying capacity of a pile.
(16)
2. What is meant by Negative skin friction in pile foundation? Explain briefly.
(16)
3. Explain the settlement of pile groups with neat sketch.
8
(16)
4. What are the different types of pile? Explain their functions.
(16)
5. Explain group capacity of piles by different methods.
(16)
6. What are the various factors influencing the selection of pile?
(16)
7. Explain in detail about the cyclic load test on pile.
(16)
8. (a) A pile is driven with a single acting steam hammer of weight 15kN with a
free fall of 900mm. The final set, the average of the last three blows, is 27.5mm.
Find the safe load using the Engineering News formula.
(8)
(b) A pile is driven in uniform clay of large depth. The clay has unconfined
compression strength of 90 KN/m2. The pile is 30cm diameter and 6m long.
Determine the safe frictional resistance of the pile, assuming a FOS of 3.
Assume the adhesion factor α = 0.7.
(8)
9. A square pile group of 9 piles passes through a recently filled up material of
4.5m depth. The diameter of the pile is 30cm and pile spacing is 90cm centre to
centre. If the unconfined compression strength of the cohesive material is 60
KN/m2 and unit weight is 15 kN/m3, compute the negative skin friction of the pile
group.
(16)
10. Explain the construction of under- reamed piles with neat sketch.
9
(16)
UNIT V
RETAINING WALLS
Plastic equilibrium in soils – active and passive states – Rankine‟s theory –
cohesionless and cohesive soil – Coulomb‟s wedge theory – Condition for critical
failure plane – Earth pressure on retaining walls of simple configurations –
Culmann Graphical method – pressure on the wall due to line load – Stability
analysis of retaining walls.
UNIT V: RETAINING WALLS
Part A (2 marks for each question)
1. Define conjugate stresses.
2. How do you check the stability of retaining walls?
3. Define angle of repose.
4. What are the assumptions made in Rankine’s theory of earth pressure?
5. What is the assumption made in Coulomb’s wedge theory?
6. How to prevent land sliding?
7. Write down any two assumptions of Rankine’s theory.
8. Distinguish Coulomb’s wedge theory from Rankine’s theory.
9. Define active earth pressure.
10. Write short notes on passive earth pressure.
11. Write any three assumptions made in Coulomb’s wedge theory.
12. What are the uses of stability number?
13. Write any three assumptions made in analysis of stability of slope.
14. Mention a factor which leads to the failure slopes.
15. List the types of slope failures.
16. Write short notes on translational failure.
17. What is wedge failure?
18. What are types of rotational slope failures?
19. Under what circumstances compound failure occurs?
20. What is isobar?
Part B (16 marks for each question)
1. Explain the active and passive states of earth pressure acting on a retaining
wall.
(16)
2. Explain the Coulomb wedge theory with neat sketch.
10
(16)
3. Explain the Rebhann’s graphical method for active earth pressure calculation.
(16)
4. Explain the Culmann’s graphical method and the effect of line load.
(16)
5. Explain the Rankine’s theory for various backfill conditions to calculate active
state earth pressure.
(16)
6. A vertical wall with a smooth face is 7.2m high and retains soil with a uniform
surcharge angle of 9°. If the angle of internal friction of soil as 27°, compute the
active earth pressure and passive earth resistance assuming ϒ = 20 KN/m3.
(16)
7. A retaining wall, 6m high, retains dry sand with an angle of internal friction of
30° and unit weight of16.2 KN/m3. Determine the earth pressure at rest. If the
water table rises to the top of the wall, determine the increase in thrust on the
wall. Assume the submerged unit weight of sand as10 KN/m3.
(16)
8. A wall, 5.4m high, retains sand. In the loose state the sand has void ratio of
0.63 and Ø = 27°, while in the dense state, the corresponding values of void ratio
and Ø are 0.36 and 45° respectively. Compare the ratio of active and passive
earth pressure in the two cases, assuming G = 2.64.
(16)
9. a) List criteria for a satisfactory design of a gravity retaining wall.
(8)
b) A retaining wall, 7.5m high, retains a cohesion less backfill. The top 3m of the
fill has a unit weight of 18 KN/m3 and Ø = 30° and the rest has unit weight of 24
KN/m3 and Ø = 20°. Determine the pressure distribution on the wall.
(8)
10. A gravity retaining wall retains 12 m of a back fill, r = 17.7 kN/m 3, r sub =
10kN/m3.  = 25 with a uniform horizontal surface. Assume the wall interface to
be vertical, determine the magnitude and point of application of the total active
pressure.
If the water table is at a height of 6m, how far do the magnitude and the
point of application of active pressure changed?
(16)
11
UNIT –I
PART – A
1. What is significant depth? (NOV/DEC 2009)
2. What is detailed exploration? (NOV/DEC 2009)
3. Define:
(a) Area ratio
(b) Inside clearance of sampler(MAY/JUNE 2009)
4. List out different methods of sampling techniques. (MAY/JUNE 2009)
5. A SPT is conducted in fine sand below water table and a value of 27 is obtained for N.
what is the corrected value of N? (NOV/ DEC 2010)
6. What is bore log? (NOV/ DEC 2010)
7. One sampler has an area ratio of 10% while another has 18%, which of those samples
do you prefer and why? (NOV/ DEC 2010)
8. Define recovery ratio and how it is useful in judging the nature of soil. (NOV/ DEC
2010)
9. What are the methods of site exploration? (APRIL/MAY 2011)
10. List out the various boring methods. (APRIL/MAY 2011)
11. List any two objectives of foundation. (APRIL/MAY 2011)
12. Under what circumstances friction piles are adopted? (APRIL/MAY 2011)
13. How do you decide the depth of soil exploration? (APRIL / MAY 2010)
14. Distinguish between representative and non-representative samples? (APRIL / MAY
2010)
15. Write any two purposes of site investigation. (MAY / JUNE 2010)
16. What is the first step of sub-surface exploration programme? (MAY / JUNE 2010)
17. Write any two types of boring. (MAY / JUNE 2010)
18. Name the most commonly used in-situ test for cohesion less soil. (MAY / JUNE 2010)
PART – B
1. Explain different methods of obtaining undisturbed samples in (NOV/DEC 2009)
(i). clay layer and
(ii). Sand deposits
2. Explain the electrical resistivity method in detail. (NOV/DEC 2009, MAY / JUNE
2010)
3. Write explanatory notes on the following
a. Chunk sampling
b. Rotary drilling
c. Bore hole log
d. Electrical resistivity method of ground exploration. (MAY/JUNE 2009)
4. Explain with neat sketches any three type of samplers. (MAY/JUNE 2009)
5. Write short notes on block or chunk sampling. (NOV/ DEC 2010)
How do you select suitable foundation based on soil conditions? (NOV/ DEC 2010)
12
6. Briefly explain standard penetration test and the corrections to be applied to find N
value. (NOV/ DEC 2010, APRIL/MAY 2011, MAY / JUNE 2010)
7. (i) What are the objectives of soil exploration? (APRIL / MAY 2010)
(ii) Write down the procedure to conduct standard penetration test. (APRIL / MAY
2010)
8. Discuss the selection of foundation based on soil condition. (APRIL / MAY 2010)
9. Explain different types of borings for soil exploration. (MAY / JUNE 2010)
13
UNIT –II
PART – A
1. What is spread footing? (NOV/DEC 2009)
2. Sketch the pressure distribution beneath a rigid footing on cohesive soil. (NOV/DEC
2009)
3. What is safe bearing capacity? (NOV/DEC 2009, NOV/ DEC 2010)
4. Write down the components of settlement. (MAY/JUNE 2009)
5. Define punching shear failure. (MAY/JUNE 2009)
6. Define settlement and list its components. (NOV/ DEC 2010)
7. What are the conditions to be followed for locating the foundations in a sloping
ground? (NOV/ DEC 2010)
8. Write the various factors affecting the bearing capacity of soil? (NOV/ DEC 2010)
9. Write any two limitations of plate load test(NOV/ DEC 2010)
10. What is meant by safe bearing pressure? (APRIL/MAY 2011)
11. Write SBC equation for strip footing as per Terzaghi’s analysis. (APRIL/MAY 2011)
12. What is meant by immediate settlement? (APRIL/MAY 2011)
13. What are the types of shallow foundation? (APRIL/MAY 2011)
14. List the factors which affect bearing capacity of soil? (APRIL / MAY 2010)
15. Write down the components of settlement in soil? (APRIL / MAY 2010)
16. Define allowable bearing pressure. (MAY / JUNE 2010)
17. What is the principle of Rankine’s analysis? (MAY / JUNE 2010)
18. What is the assumption of Terzaghi related to base of the footing? (MAY / JUNE
2010)
19. As per Terzaghi, which equation governs the shear strength of soil? (MAY / JUNE
2010)
PART – B
1. Explain the Terzaghi’s analysis for determining the safe bearing capacity of the soil.
(NOV/DEC 2009)
2. Explain the plate load test for determining the ultimate bearing capacity of the soil.
(NOV/DEC 2009)
3. Calculate the net ultimate bearing capacity of a rectangular footing 1.8m x 3.6m in plan
founded at a depth of 1.6m below ground surface. The load on the footing acts at an
angle of 16° to the vertical and is eccentric in the direction of width by 15cm. the unit
weight of the soil is 18kN/m3. The rate of loading is slow and hence the effective shear
strength can be in the analysis, having c’ = 15kN/m2
at a depth of 2m below the ground surface. Use IS method. (MAY/JUNE 2009)
4. Derive Terzhaghi’s general equation for computing bearing capacity of soils.
(MAY/JUNE 2009)
5. Explain the various causes of settlement and how to minimize it. (NOV/ DEC 2010)
Compare general shear failure with shear failure.
14
6. The footing of a column is 2.25m square and is founded at a depth of 1m on a cohesive
soil of unit weight 17.5kN/m3 angle of internal friction is zero and factor of safety is 3.
Terzaghi’s factors for φ = 0 are Nc = 5.,7 Nq = 1, Nr = 0(NOV/ DEC 2010)
7. A square footing 1.2m x 1.2m rests at a depth of 1m in a saturated clay layer 4m deep.
The clay is normally consolidated, having an unconfined compressive strength of
40N/m2, the soil has a LL of 30%, rsat = 17.8 kN/m3, w = 28% & G = 2.68. Determine
the load which the footing can carry safety with a factor of safety of 3 against shear.
Also, determine the settlement if the footing is loaded with this safe load. Use
Terzaghi’s analysis for bearing capacity. (APRIL/MAY 2011)
8. A square man concrete footing supporting a load of 3250kN extends form ground level
to 3.5m deep into a clay structure. What will be the size of the footing allowing for a
factor of safety of 4.0? unit weight of concrete 25kN/m3. Shear strength of soil
0.12N/mm2. Adhesion of clay with footing is 25kN/m3. The adhesion may be supported
to act over a depth of 12 from the bottom of the foundation. For φ = 0°, the values of
Nc=2.7, Nq=1, Nr=0. (APRIL/MAY 2011)
9. (i) Write a short note on the method of minimizing settlement. (APRIL / MAY 2010)
(ii) Plate load tests were conducted in a C Soil, on plate of two different sizes and the
following results were obtained
LOAD
SIZE OFPLATE
SETTLEMENT
50KN
0.3X0.3m
25mm
110KN
0.6x0.6m
25mm
Find the size of square footing required to carry a load of 1000KN at the same
specified
settlement of 25mm. (APRIL / MAY 2010)
10. Determine the ultimate bearing capacity of a strip footing, 1.2m wide and having the
depth of foundation of 1m. Use Terzaghi theory and assume general shear failure. Take
Φ=35˚(MAY / JUNE 2010
15
UNIT –III
PART – A
1. What is gross pressure intensity? (NOV/DEC 2009)
2. Under what circumstances mat or raft foundation are used? (MAY/JUNE 2009)
3. State the assumptions made in the conventional structural design of footings.
(MAY/JUNE 2009)
4. Define combined footing and in what situation it is preferred? (NOV/ DEC 2010)
5. Write any two advantages of the floating foundation. (NOV/ DEC 2010)
6. State the reason why higher settlement is permissible in clay than in sand. (NOV/ DEC
2010)
7. What do you understand by truly elastic foundation? (APRIL/MAY 2011)
8. How immediate settlement can be expressed based on theory of elasticity?
(APRIL/MAY 2011)
9. Under what circumstances strap footing is adopted? (APRIL/MAY 2011)
10. What is meant by floating foundation? (APRIL/MAY 2011)
11. Under what circumstances strap footing is provided? (APRIL / MAY 2010)
12. Draw the contact pressure distribution below rigid footing. (APRIL / MAY 2010)
13. Classify Foundation Settlement under loads. (MAY / JUNE 2010)
14. What is the reason for structural collapse of soil? (MAY / JUNE 2010)
15. Based on which theory consolidation settlement in clays is calculated? (MAY / JUNE
2010)
16. Why foundation settlement prediction is not accurate often? (MAY / JUNE 2010)
PART – B
1. Explain the design procedure of a rectangular footing in detail. (NOV/DEC 2009)
2. Explain the design procedure of a combined footing in detail(NOV/DEC 2009)
3. Proportion a strap footing for the following data:
Allowable pressure: 150 kN/m2 for DL + reduced LL
225 kN/m2 for Dl + LL
Column loads:
Column A
column B
Dl
500 kN
600 kN
LL
450 kN
800 kN
Proportion the footing uniform pressure under DL + reduced LL. Distance c/c
column 5.4m. Projection beyond column a not to exceed 0.5m. (MAY/JUNE 2009,
APRIL / MAY 2010)
4. A trapezoidal footing to be provided to support two square columns of 30cm and 50 cm
sides respectively. Columns are 6m apart and the safe bearing capacity of soil is
400kN/m2. The bigger column carries 5000kN and the smaller column 3000kN. Design
suitable size of the footing so that it does not extend beyond the faces of the column.
(MAY/JUNE 2009)
16
5. A building is to be supported on a R.C.C raft foundation of dimensions 12m x 18m.
The subsoil is clay which has an average unconfined compressive strength of 15 kN/m2.
The pressure on the soil due to the weight of the building and the loads it will carry is
expected to be 130kN/m3 at the base of the raft. If the unit weight of the excavated soil
is 18kN/m3, determine the depth at which the bottom of the raft should be placed to
provided a factor of safety of 3 against shear failure. (APRIL/MAY 2011)
6. (i) Find the plan dimension of a rectangular combined footing to support two columns
250x250mm and 300x300mm carrying loads of 400KN and 600KN respectively. The
columns are spaced at 4mc/c. The allowable bearing capacity of the soil is 200KN/m².
(ii) If one of the column is on the boundary line. Find the dimensions of the
combined footing for
the above case. (APRIL / MAY 2010)
7. A footing 2.4m square carries a gross pressure of 350KN/m2 at a depth of 1.20m in
sand. A saturated unit weight of sand is 20KN/m3 and the unit weight of sand above
water table is 16kn/m3. The shear strength parameters are C´ =0 and Φ´=30° (for
Φ´=30° Nq=22, Nγ=20). Determine the factor of safety with respect to shear failure for
the following cases:
(i) W.T. is 5m below the ground level
(ii) W.T. is 1.2m below the ground level. (APRIL / MAY 2010)
8. Describe the step by step procedure for the design of a combined footing. (MAY /
JUNE 2010)
17
UNIT –IV
PART – A
1. What is friction pile? (NOV/DEC 2009)
2. On what basis, is the allowable load on a pile determined? (NOV/DEC 2009)
3. Define negative skin friction in pile. (MAY/JUNE 2009)
4. How will you find the efficient of the pile group? (MAY/JUNE 2009)
5. Define feld’s rule(NOV/ DEC 2010)
6. What is test pile? (NOV/ DEC 2010)
7. Define fender piles. (NOV/ DEC 2010)
8. What is negative skin friction? (NOV/ DEC 2010)
9. What is meant by negative skin friction? (APRIL/MAY 2011)
10. What is the need of pressure piles? (APRIL/MAY 2011)
11. State any two functions of piles foundation. (APRIL/MAY 2011)
12. Define pile cap.(APRIL/MAY 2011)
13. Define negative skin friction? (APRIL / MAY 2010)
14. What are the methods available to determine the load carrying capacity of pile?
(APRIL / MAY 2010)
15. What is the main condition for the usage of piles? (MAY / JUNE 2010)
16. Classify piles according to materials. (MAY / JUNE 2010)
17. What do you mean by sheet pile? (MAY / JUNE 2010)
18. What are the in-situ penetration tests for pile capacity? (MAY / JUNE 2010)
PART – B
1. A reinforced concrete pile weighing 30 kN (including of helmet and dolly) is driven by
a drop hammer weighing 40kN and having an effective fall of 0.80m. the average set
per blow is 1.40cm. The total temporary elastic compression is 1.80cm. Assuming the
coefficient of restitution as 0.25 and a factor of safety of 2. Determine the ultimate
bearing capacity and allowable load for the pile. (NOV/DEC 2009)
2. Design a friction pile group to carry a load of 3000kN including the weight of the pile
cap at a site where the soil is uniform clay to a depth of 20m, underlain by rock.
Average unconfined compressive strength of the clay 70kN/m2. The clay may be
assumed to be normal sensitivity and normal loaded, with liquid limit of 60%. A factor
of safety of 3 is required against shear failure. (NOV/DEC 2009)
3. A square pile group of 16 pile penetrates through a filled up soil 3m depth. The pile
diameter of 250mm and pile spacing is 0.75m. the unit cohesion of the material is
18kN/m2 and the unit weight of soil is 15kN/m3. Draw plan and section elevation of the
pile group and compute the negative skin friction on the group. (MAY/JUNE 2009)
4. Explain with neat sketches the construction of a single under reamed pile.
(MAY/JUNE 2009)
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5. A group of 16 piles of 50 cm diameter is arranged with a centre to centre spacing of
1m. the piles are 10m long and are embedded in soft clay with cohesion of 30kN/m2.
Take m = 0.6 for shear mobilization around each pile. Determine the ultimate load
capacity of the pile group neglecting the bearing resistance. (NOV/ DEC 2010)
6. How the piles are classified? Explain them in details. (NOV/ DEC 2010)
7. Describe the method of conducting a pile load test. (NOV/ DEC 2010)
8. Design a friction piles group to carry a load of 3000kN including the weight of the pile
cap at a site where the soil is uniform clay to a depth of 20, underlain by rock. Average
unconfined compressive strength of the clay is 70 kN/m3. The clay may be assumed to
be normal sensitivity and normaly loaded, with liquid limit 60%. A factor of safety of 3
is required against shear failure. (APRIL/MAY 2011)A 200mm diameter, 8m long
piles are used as foundation for a column in a uniform deposit of medium clay
(unconfined compressive strength = 100 kN/m3 and adhesion factor = 0.9). There are
nine arranged in a square pattern of 3 x 3. For a group efficiency = 10, find the spacing
between the piles (neglect bearing). (APRIL/MAY 2011)
9. a reinforced concrete pile weinging 40KN is driven by a drop hammer weighing 40KN
and having an effective fall of 0.8m.the average set per blow is 1.4cm. the total
temporary elastic compression is 1.8cm. Assuming the coefficient of restitution as 0.25
and a factor of safty 2. Determine the ultimate bearing capacity and allowable load for
the pile. (APRIL / MAY 2010)
10. (i). Explain the factors governing the efficiency of group piles. (APRIL / MAY 2010)
(ii). write short notes on
(i) Forces acting on pile cap.
(ii) Under reamed pile construction. (APRIL / MAY 2010)
11. A concrete pile, 300mm dia is driven in to a medium dense sand (Φ = 35˚ £ = 21kN/m³
K =1 tan ζ = 0.7) for a depth of 8m. Estimate the safe load. Take F O S = 2.5(MAY /
JUNE 2010)
12. Explain the concept of relative skin friction and under reamed piles. (MAY / JUNE
2010)
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UNIT –V
1. What is surcharge?
2. What is failure wedge?
3. What do you meant by critical height of unsupported cuts in clay soils? (MAY/JUNE
2009)
4. Write down the assumptions made in the coulomb’s theory. (MAY/JUNE 2009)
5. Define surcharge angle. (NOV/ DEC 2010)
6. Write the assumption in Rankine’s earth pressure theory. (NOV/ DEC 2010)
7. Define coefficient of earth pressure at rest. (NOV/ DEC 2010)
8. Define passive earth pressure. (NOV/ DEC 2010)
9. What is meant by surcharge? (APRIL/MAY 2011)
10. What is meant by plastic equilibrium? (APRIL/MAY 2011)
11. What is meant active earth pressure? (APRIL/MAY 2011)
12. What is co-efficient of earth pressure? (APRIL/MAY 2011)
13. How do you check the stability of retaining wall? (APRIL / MAY 2010)
14. Distinguish Rankine’s theory from coulomb’s wedge theory. (APRIL / MAY 2010)
15. Up to what height cantilever Retaining wall is found to be economical? (MAY / JUNE
2010)
16. What is the range of factor of safety for no overturning to occur for the retaining wall?
(MAY / JUNE 2010)
17. For Which soil Rankine’s Original theory was formulated? (MAY / JUNE 2010)
18. What are the assumptions of Coulomb’s wedge theory related to backfill? (MAY /
JUNE 2010)
PART – B
1. Explain the coulomb’s wedge theory in detail. (NOV/DEC 2009)
2. Explain Rankine’s theory of active earth pressure for a submerged backfill.
(NOV/DEC 2009)
1. A retaining wall 6m high, vertical back, supports a saturated clay soil with a horizontal
surface. The properties of the backfill are:
Cu = 0, Cu = 35 kN/m2, γ = 17 kN/m3
Assuming the back of the wall to be smooth, determine
i.
The depth of tension cracks.
ii.
The critical depth of a vertical cut.
iii. The total active thrust against the wall and its point of application, if cracks are
formed in the tension zone.
2. Drive the expression for Rankine’s active earth pressure on retaining walls due to a
cohesion backfill. (MAY/JUNE 2009)
3. A smooth backed vertical wall is 4m height and retains a soil with a bulk unit weight of
18kN/m3 and φ = 30. The top of the soil is level with the top of the wall and is
horizontal. If the soil surface caries a uniformly distributed load of 36 kN/m 2.
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4.
5.
6.
7.
8.
Determine the total active thrust per meter length of the wall and its point of
application. (NOV/ DEC 2010)
A retaining wall, 4m high supports a backfill (c =20 kN/m2; φ = 30°; γ = 20 kN/m3)
with horizontal top, flush with the top of the wall. The backfill carries a surcharge of 20
kN/m2. If the wall is pushed towards the backfill, compute the total passive pressure on
the wall and its point of application. (APRIL/MAY 2011)
A retaining wall has smooth vertical back. The backfill has a horizontal surface in level
with the top of the wall. There is uniformly distributed surcharge load 36kN/m2
intensity over the backfill. The unit weight of the backfill is 18 kN/m 3; its angle of
shearing resistance is 30° and cohesion is zero. Determine the magnitude and point of
application of active pressure per meter length of the wall. (APRIL/MAY 2011)
Explain with a neat sketch the culmann’s method of calculating active earth pressure.
(APRIL / MAY 2010)
A retaining wall 6m high retains sand with Φ=30° and unit weight 24KN/m3 up to a
depth of from top. From 3m to 6m, the material is a cohesive soil with c= 20 KN/m 2
and Φ=20°. Unit weight of cohesive soil is 18 KN/m3. A uniform surcharge of
100KN/m2 is acting on the top of the soil. Determine the total lateral pressure acting on
the wall and its point of application. (APRIL / MAY 2010)
Describe the principles of design of Retaining walls. (MAY / JUNE 2010)
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