# Foundation Engineering

## Trending Questions

**Q.**The ultimate bearing capacity of a soil is 300 kN/m2. The depth of foundation is 1 m and unit weight of soil is 20 kN/m3. Choosing a factor of safety of 2.5, the net safe bearing capacity is

- 100 kN/m2
- 112 kN/m3
- 80 kN/m3
- 100.5 kN/m3

**Q.**

What is damping and its types?

**Q.**The lateral earth pressure coefficient of a soil, Ka for active state, Kp for passive state and K0 for at-rest condition, compare as

- K0<Ka<Kp
- Ka<K0<Kp
- Ka<Kp<K0
- Kp<K0<Ka

**Q.**Taylor's stability number Sn is given by which one of the following expressions ? (c is cohesion , Fc is fcator of safety, γ is density of soil and H is the height of the slope).

- cFcγ
- cγH
- cFcγH
- cFc(γ+H)

**Q.**Efficiency of a pile group is defined as

- Load carried by the largest pile in the groupLoad carried by the smallest pile in the group
- Maximum load carried by a pile in the groupMinimum load carried by a pile in the group
- Minimum load carried by a pile in the groupMaximum load carried by a pile in the group
- Average load carried by a pile in the groupLoad carried by a single pile

**Q.**A raft foundation is to be constructed on a sandy soil. The maximum differential settlement and limiting maximum settlement as recommended by Indian standard code are :

Max. differential Limiting max.

settlement settlement

- 40mm 65mm to 10mm
- 40 mm 40mm to 65 mm
- 25mm 65mm to 100mm
- 25mm 40mm to 65mm

**Q.**The total active thrust on a vertical wall 3m high retaining a horizontal sand backfill (unit weight γt=20KN/m3, angle of shearing resistance ϕ′=30∘) when the water table is at the bottom of the wall, will be:

- 30 KN/m
- 35 KN/m
- 40 KN/m
- 45 KN/m

**Q.**An unsupported excavation is made to the maximum possible depth in a clay soil having γt = 18kN/m3, C=100kN/m2, ϕ=30∘. The active earth pressure, according to Rankine's theory, at the base level of the excavation is

- 115.47kN/m2
- 54.36kN/m2
- 27.18kN/m2
- 13.0kN/m2

**Q.**A 6m height retaining wall having smooth vertical face and horizontal backfill. Top 3 m thick layer is sand ϕ=30∘ while the bottom layer is 3 m thick clay (C = 20 kPa). Assume unit weight for both sand and clay as 18kN/m3. The total active earth pressure per unit length of the wall (in K=kN/m) is

- 150
- 216
- 156
- 196

**Q.**Active earth pressure per meter length on the retaining wall with a smooth vertical back as shown in the given figure will be

- 81 t
- 27 t
- 2 t
- 1 t

**Q.**The value of bearing capacity factor for cohesion, N′c, for soil as per meyerhof, is taken as

6.2

12.0

9.0

5.14

**Q.**The ultimate bearing capacity of a surface strip footing on clay, according to Terzaghi's theory, is

Where C - unit cohesion,

qu = unconfined compressive strength,

and B - width of footing

- 5.7 C
- 5.14 C
- quB
- 9 C

**Q.**Why are weep holes provided at the back of retaining walls?

- To reduce the active earth pressure on the walls.
- To reduce the build-up of hydrostatic pressure.
- To provide better compaction.
- To increase the passive earth pressure.

**Q.**A footing 2 m × 1 m exerts a uniform pressure of 150 kN/m2 on the soil. Assuming a load disperesion of 2 vertical to 1 horizantal, the average vertical stress (kN/m2) at 1.0 m below the footing is

- 50
- 75
- 80
- 100

**Q.**Minimum centre to centre spacing of friction piles of diameter (D) as per BIS code is

- 1.5D
- 2D
- 2.5D
- 3D

**Q.**The bearing capacity factors Nc Nq and Nγ are functions of

- width and depth of footing
- density of soil
- cohesion of soil
- angle of internal friction of soil

**Q.**The standard penetration resistance value obtained in a deep deposit of sand at a depth of 6.0 m was 28. The unit weight of sand is 18.0kN/m3. What is the corrected value of number of blows for overburden pressure?

- 60
- 57
- 59
- 55

**Q.**A retaining wall of height 8 m retains dry sand. In the initial state, the soil is loose and has a void ratio of 0.5, γd=17.8kN/m3 and ϕ=30∘, Subsequently, the backfill is compacted to a state where void ratio is 0.4, γd=18.8kN/m3 and ϕ=35∘, The ratio of initial passive thrust to the final passive thrust, according to Rankine's earth pressure theory, is

- 0.38
- 0.64
- 0.77
- 1.5

**Q.**A strip footing of width 1.5 m is laid at a depth of 1 m. The ultimate bearing capacity of soil (in kN/m2) is ?

For ϕ=30∘, (Nc=19, Nq=8.3, Nγ=5.7)

- 403.5
- 416.3
- 424.8
- 432.6

**Q.**The ultimate bearing capacity of a square footing on surface of a saturated clay having unconfined compression strength of 50 kN/m2 (using skempton's equation) is

- 250kN/m2
- 180kN/m2
- 150kN/m2
- 125kN/m2

**Q.**In cohesive soils the depth of tension crack (Zcr) is likely to be

- Zcr≥2Cγtan(45∘−ϕ2)
- Zcr≥2Cγtan(45∘+ϕ2)
- Zcr≥4Cγtan(45∘−ϕ2)
- Zcr≥4Cγtan(45∘+ϕ2)

**Q.**The width and depth of a footing are 2 and 1.5 m respectively. The water table at the site is at a depth of 3 m below the ground level. The water table correction factor for the calculation of the bearing capacity of soil is

0.875- 1.000

0.925- 0.500

**Q.**If the coefficient of active earth pressure is 1/3, then what is the value of the coefficient of passive earth pressure?

- 1/9
- 1/3
- 3
- 1

**Q.**Westergaard's formula for vertical stress gives greater value of stress than that by the Boussinesq's formula, when r/z exceeds

- 1.5
- 2.5
- 3.5
- 4.0

**Q.**The group efficiency of pile group

- Will be always less than 100%
- Will be always greater than 100%
- May be less than 100% or more than 100%
- Will be more than 100% for pile group in cohesion less soils and less than 100% for those in cohesive soils

**Q.**The contact pressure distribution under a rigid footing on a cohesionless soil would be

- Uniform throughout
- zero at centre and maximum at edges
- zero at edges and maximum at centre
- maximum at edges and minimum at centre

**Q.**As per Terzaghi's equation, the bearing capacity of strip footing resting on cohesive soil (c=10kN/m2) for unit depth and unit width (assume Nc as 5.7) is

- 47kN/m2
- 57kN/m2
- 67kN/m2
- 77kN/m2

**Q.**The vertical stress at some depth below the corner of a 2 m × 3 m rectangular footing due to a certain load intensity is 100KN/m2. What will be the vertical stress in KN/m2 below the centre of a 4 m × 6m rectangular footing at the same depth and same load intensity?

- 25
- 100
- 200
- 400

**Q.**The bearing capacity of a rectangular footing of plane dimension 1.5 m × 3 m resting on the surface on a sand deposit was estimated as 600 kN/m2 when the water table is far below the base of the footing. The bearing capacities in kN/m2 when the water level rises to depths of 3 m, 1.5 m and 0.5 m below the base of the footing are

- 600, 600, 400
- 600, 450, 350
- 600, 500, 250
- 600, 400, 250

**Q.**Standard penetration test (SPT) was conducted at a site. The recorded values of blow count for every 15 cm penetration at depth of 1 m are 5, 9 and 10 respectively. The water table was at the ground surface. The grain size classification showed that the size contained 40% fine sand and 60% silt. the value of SPT blow count(N) that should be used for overburden correction is ..........

- 19