DEPARTMENT OF CIVIL ENGINEERING LIST OF...

OXFORD ENGINEERING COLLEGE (NAAC Accredited with ”B” Grade )

DEPARTMENT OF CIVIL ENGINEERING

LIST OF QUESTIONS

YEAR/SEM : III/ V STAFF NAME : K.VEERASELVAM/AP/CIVIL SUB,CODE : CE 6502 SUB. NAME : FOUNDATION ENGINEERING

UNIT-I SITE INVESTIGATION AND SELECTION OF FOUNDATION

PART A - (Two marks)

1. What is soil exploration? (April/May 2004)

2. Define Area ratio. (April/May 2004)

3. How will you reduce the area ratio of a sampler? (Nov/Dec 2005)

4. When thin walled sampler is used for sampling? (Nov/Dec 2005)

5. Explain Representative and Non-Representative Samples. (May/June 2009)

6. What is significant depth? (Nov/Dec 2009)

7. What is detailed Exploration? (Nov/Dec 2009), (Nov/Dec 2012)

8. What are the factors affecting quality of a sample? (Nov/Dec 2010)

9. How is the depth of exploration decided? (Nov/Dec 2010)

10. What are the various methods of site investigation? (Nov/Dec 2010)

11. List the field tests used in subsurface investigations. (Nov/Dec 2013)

12. Write the uses of bore log report. (Nov/Dec 2012)

13. What is meant by inside and outside clearance? What is its use? (Nov/Dec 2013)

14. What are the limitations of hand augers in soil exploration? (May/June 2012)

15. What are the guidelines in terms of inside and outside clearance for obtaining undisturbed sample?

(May/June 2012)

16. What is site reconnaissance? (May/June 2013)

17. What is the objective of site investigation? (May/June 2013)

18. The internal diameter of a sampler is40mm and the external diameter is 42mm. Will you consider the sample

obtained from the sampler as disturbed or undisturbed?

19. What are the stages to be considered in sub surface investigation?

20. One sampler has an area ratio of 10 % while another has 18 % which of those samples do you prefer? Why?

(Nov/Dec 2010)

21. List the types of soil samplers. (Apr/May 2011)

22. Define Chunk samples. (May/June 2009)

23. What are the information obtained in the general exploration? (Nov/Dec 2010)

24. Define recovery ratio. How it is useful in judging the nature of the soil? (Nov/Dec 2010)

25. What is the function of spring core catcher?

PART B - ( Sixteen marks )

1. Briefly explain with neat sketch Standard Penetration Test and the correction to be applied to find „N‟ value.

(April/May 2004), (May/June 2009) , (Nov/Dec 2011), (April/May 2004), (May /June 2012), (Nov/Dec 2013).

2. Explain in detail the geophysical methods of soil explorations with neat sketch. (Nov/Dec 2012), (Nov/Dec 2013), (May /June 2013).

3. Describe the various methods of drilling bore holes for sub surface investigations.(April/May 2011).

4. Discuss the features of bore log report in detail. (Nov/Dec 2010), (May/June 2012)

5. Explain in detail the cone penetration test with sketches.

6. Explain in detail the various types of samplers with sketches.

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UNIT-II SHALLOW FOUNDATION


(FIRST HALF)

1. What is ultimate bearing capacity? (April/May 2004), (May/June 2013)

2. What is consolidation settlement? (April/May 2004)

3. List the various components of settlement. (Nov/Dec 2005), (April/May 2010)

4. Give the Terzaghi‟s bearing capacity equation of strip footing for local shear failure.

5. Compare general and local shear failure. (May/June 2009)

6. What is meant by allowable settlement? (May/June 2009)

7. List the factors affecting bearing capacity of soil. (April/May 2010)

8. What is spread footing? (Nov/Dec 2009)

9. Sketch the pressure distribution beneath a rigid footing on cohesive and cohesionless soil. (Nov/Dec 2009),

(May/June 2012)

10. Define safe bearing capacity. (Nov/Dec 2010)

11. What is the equation used to determine the immediate settlement? (Nov/Dec 2010)

12. What are the criteria used for the determination of bearing capacity? (Nov/Dec 2010)

13. A footing was designed based on ultimate bearing capacity arrived for the condition of water table at the

ground surface. If there is a chance for raise in water level much above the ground level do you expect any

change in the bearing capacity, why? (Nov/Dec 2010)

(SECOND HALF)

14. A footing 2m square is laid at a depth of 1.3 m below the ground surface. Determine the net ultimate bearing

capacity using BIS formula. Take γ =20 kN/m3, ɸ =30˚ and c= 0. For ɸ =30˚, take Nc =30.1, Nq =18.4 and Nγ

= 22.4. (April/May 2011)

15. Define punching shear failure. (Nov/Dec 2012)

16. What is mean by swelling potential? (Nov/Dec 2012)

17. What is net pressure intensity? (May/June 2013)

18. What is safe bearing pressure? (May/June 2013)

19. What is the total settlement of a footing? (May/June 2013)

20. What is the effect of rise of water table on the bearing capacity and the settlement of a footing on sand?

(Nov/Dec 2013)

21. Define allowable bearing pressure.

22. Define settlement and its types.

23. What are the types of shallow foundation ? (April/May 2011)

24. What are the types of shallow foundation ?

25. Write any four methods for determining the bearing capacity of soil.


(FIRST HALF)

1. Explain Terzaghi‟s bearing capacity theory.

2. Explain plate load test with sketch.

3. (a) A footing 2m square is located at a depth of 1.5 m in a sand deposit. Borings have indicate that the average corrected N value at the site is 25. Water table is at the depth of 2m below the ground surface. Determine the net allowable bearing pressure for a factor of safety of 3 against shear failure and permissible settlement of 25 mm. (10)

(b)Write a short on method of minimizing the settlement (6)

(SECOND HALF)

4. (i) Explain in detail the various types of shear failure. (ii) List the various factors that affect the depth of foundation.

5. A strip footing carries a load intensity of 400kN/m2 at a depth of 1.2 m in a sand. The saturated unit weight of the sand is 19.5 kN/m3 and unit weight above water table is 16.8kN.m3 a shear strength parameters of c=0 and φ=35o. Determine the factor of safety with respect to shear failure for the following cases of location of water table.

(i) Water table is 4m below the G.L (ii) Water table is 1.2 m below the ground level. (iii) Water table is at G.L (iv) Water table is just at base of footing.

Use Terzaghi’s equation.(For φ=35o, Nq=41.4, Ny=42.4)

6. Compute the safe bearing capacity of the square footing 1.5mx1.5m is located at a depth 1m below the ground level in a sandy soil has a unit weight of 20kN/m3 and ɸ=300( Nc=17.7, Nq=7.4 Ny=7.4). Assume factor of safety is 3 and the water table is very deep.

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UNIT-III

FOOTINGS AND RAFTS


1. When trapezoidal combined footings are provided?

2. Give the advantages of floating foundation.

3. Under what circumstances, a strap footing is adopted?

4. What is a mat foundation?

5. Where mat foundation is used?

6. What are types of foundation?

7. Define floating foundation?

8. What are the assumptions made in combined footing?

9. List the different types of raft foundation.

10. Under what circumstances, a raft footing is adopted?

11. What is the function of strap beam in a strap footing?

12. Differentiate shallow and deep foundation.

13. What are the methods of design for raft foundation?

14. How do you identify the expansive soil?

15. Differentiate flexible footing from the rigid footing.

16. What are the factors on which depth of the foundation depends?

17. Draw the pressure distribution diagram beneath the rigid footing.

18. State two basic assumption made in conventional method of raft foundation.

19. How to fix the depth of the footing?

20. Specify maximum permissible settlement for isolated and raft foundation on sand and clayey soil.

21. List the types of foundation.

22. What do you understand by truly elastic foundation?

23. What is continuous footing?

24. What is buoyant raft?

25. Enumerate the advantages of mat foundation.


1. Explain in details about the design procedure for rectangular and trapezoidal combined footing with neat sketches.

2. Explain in detail the contact pressure distribution below the footings and rafts.

3. Define mat foundation. What are the various types of raft foundations?

4. Design a reinforced concrete rectangular combined footing for two columns A and B located 3.6 meters apart. The sizes of the columns are 400mm × 400mm and 600mm ×600mm and the loads on them are 1000kN and 1500kN respectively. The projections of footing beyond the axis of the columns A are limited to 590mm. The limiting bearing capacity of the soil is 420 kN/m2. Use M 15 concrete and Fe 415 steel.

5. Proportioning of strap footing for the following allowable pressure:

150 kN/m2 DL+ reduced LL 225 kN/m2 DL+ LL

Column loads ColumnA Column B DL 500 kN 600 kN LL 450 kN 800 kN

6. Explain the precaution to be taken during construction of foundation in a black cotton soil.(Nov/Dec 2012)

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UNIT-IV PILES


1. Define end bearing pile.

2. Define group efficiency of pile.

3. List out the type of pile based on material used.

4. How is the selection of pile carried out?

5. What are the factors consider while selecting the type of pile?

6. What are the types of hammer used for pile driving?

7. What are 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. What are the limitations of dynamic pile load test?

12. List the piles based on materials of installation

13. What are anchor piles?

14. What are fender piles?

15. Define negative skin pressure

16. What are the conditions where a pile foundation is more suitable than a shallow foundation?

17. What is meant by friction pile?

18. State any two function of pile foundation.

19. Define pile cap.

20. What are the classification of piles?

21. Define felds rule.

22. How will you find the efficiency of pile group?

23. List out the type of pile based on transfer of load.

24. What are under reamed pile? Specify its uses.

25. What are the beneficial effects induced by a pair of under reams in a pile?


1. Briefly explain static and dynamic formulae of load carrying capacity of piles.

2. A group of 9 piles with 3 piles in a row was driven into soft clay extending from ground level to a great depth. The diameter and length of piles were 30 cm and 10 cm respectively. The unconfined compression strength of clay is 70 kN/m2. If the piles were spaced at 90cm centre to centre, compute the allowable load on the pile group on the basis of shear failure criteria for a factor of safety of 2.5, neglect bearing at the tip of piles, take m = 0.6 for shear mobilization around each pile.

3. A group of 16 friction piles is to support a column load of 4000kN. The piles will be driven in four rows with four numbers in each column. The piles are 35 cm diameter. And the c/c spacing is 1m both ways. What set value must be attained by the piles when driven by a single acting 22.5kN steam hammer with 90cm stroke so that the pile group can carry the column load?

4. Explain with neat sketch about pile load test method of determination of load carrying capacity of piles. 5. Enumerate the various types of pile in detail.

6. A precast concrete pile (35cm x 35 cm) is driven by a single-acting steam hammer .Estimate the allowable

load using (a)Engineering news record formula(F.S =6) (b)Hiley’s formula (F.S=4) (c) Danish formula(F.S= 4) Use the following data.

Maximum rated energy = 3500kN-cm Weight of hammer = 35 kN Length of pile = 15 cm Efficiency of pile hammer =0.8 Co efficient of restitution =0.5 Weight of pile cap =3 kN No. of blows for last 25.4 mm =6 Modulus of elasticity of concrete=2x 107 kN/m2

Take the weight of pile as 73.5 kN

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UNIT-V RETAINING WALLS


1. Define retaining wall.

2. How do you check the stability of retaining walls?

3. Define angle of repose

4. What are the assumptions in coulomb wedge theory?

5. Distinguish Coloumb‟s wedge theory from Rankine‟s theory?

6. Why retaining walls are usually designed for active earth pressure?

7. Write down any two assumptions of Rankine‟s theory?

8. What do you understand by plastic equilibrium in soil?

9. What is surcharge angle?

10. Sketch the movement of retaining wall to retain a backfill in active states.

11. Draw the variation of earth pressure with the wall movement .

12. Why the passive earth pressure is not normally considered in the design?

13. What is surcharge?

14. What is meant by backfill?

15. What is earth pressure at rest?

16. Define passive earth pressure.

17. List out the aspects using which stability of retaining wall has been ensured.

18. What is meant by active earth pressure?

19. What is meant by surcharge?

20. What are the conditions to be satisfied while designing a retaining wall?

21. Write the types of retaining wall

22. Sketch the active earth pressure distribution diagram for a fully saturated cohesive backfill.

23. Define co-efficient of earth pressure at rest.

24. What is critical failure plane?

25. Give the design criteria of gravity retaining wall.


1. Explain Rankine‟s theory for the cases of cohesion less backfill.

2. Briefly explain the coulomb’s wedge theory and the determination of active earth pressure.

3. A smooth vertical wall is 4m height and retains a cohesive less soil with bulk unit weight of 18 kN/m3 and ɸ = 300. The top of the soil is level with the top of the wall and is horizontal. If the soil surface carries a uniformly distributed load of 36kN/m2. Determine the total active thrust per meter length of the wall and its point of application.

4. A gravity retaining wall retains 12 m of a backfill has a unit weight of 18 kN/m3, C=0 and ɸ = 300 with a

horizontal surface. Assume the wall interface to be vertical. If the water is located at a depth of 6 m from the ground level and submerged unit weight of the soil is 10 kN/m3.Determine the magnitude and point of application of the total active earth pressure.

5. Explain the active and passive state of earth pressure acting on a retaining wall. 6. A retaining wall is 4 m high . its back is vertical and it has got sandy backfill up to its top .the top of the fill

is horizontal and carries a uniform surcharge load of 85 kN/m2. Determine the active earth pressure on the wall per meter length of the wall. Water table is 1m below the top of the fill. Take

Dry density of soil = 18.5kN/m2 Moisture content of the soil below

the water table = 12% Angle of internal frictional of the soil=30o Specific gravity of the soil particles =2.65 Porosity of the back fill =30%

The wall friction may be neglected.

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