Foundation Engineering Questions and Answers Part-23

1.The bearing capacity equation for strip footing as given IS standard, can be modified on the basis of ___________
a) Shape of the footing
b) Type of soil
c) Bearing capacity
d) All of the mentioned

Answer: a
Explanation: The bearing equations applicable for strip footing shall be modified to take into account, the shape of the footings, and inclination of loading, depth of embankment and effect of water table.

2.The value of shape factor S c, S q and S γ for circular base is _________
a) 1.3, 1.2, 0.8
b) 1.3, 1.2, 0.6
c) 1.0, 1.0, 1.0
d) 1.2, 1.0 and 1.3

Answer: b
Explanation: According to IS (6403 -1981) standards, the shape factor for circle base is 1.3, 1.2 and 0.6 for S c, S q and S γ respectively.

3. The depth factor can be applied to footing only when ___________
a) Back filling is compacted
b) Shape factors are not used
c) The base of the footing is circular
d) All of the mentioned

Answer: a
Explanation: The depth factor can be applied only the back filling is done with proper compaction.

4. The effect of the water table is taken into account for bearing capacity in the form of ___________
a) Depth factor
b) Inclination factor
c) Correction factor
d) Shape factor

Answer: c
Explanation: The effect of the water table is taken into account in the form of correction factor W’ applied to the wedge term.

5. If the water table is located at the depth D, then the value of W’ is taken as ___________
a) 1
b) 0.5
c) 2
d) 0

Answer: b
Explanation: If the water table is located at the depth D or likely to rise at the base of the footing or above, then the value of W’ shall be taken as 0.5.

6. For cohesion less soils, having c=0 Indian standard code recommends that the bearing capacity can be calculated based on __________
a) Relative density
b) Standard penetration resistance value
c) Static cone penetration
d) All of the mentioned

Answer: d
Explanation: For cohesionless soils (c=0), Indian standard code recommends that the bearing capacity can be calculated i) based on relative density or ii) based on standard penetration resistance value, and iii) based on static cone penetration test.

7. The standard penetration resistance is determined at a number of selected points at intervals of __________
a) 80 cm
b) 75 cm
c) 100 cm
d) 10 cm

Answer: b
Explanation: Indian standard recommends that the standard penetration resistance is determined at a number of selected points at intervals of 75 cm in the vertical direction or change of strata if it takes place earlier.

8. The ultimate bearing capacity for cohesive soil can be calculated using the equation __________
a) q nf = c Nc.sc
b) q nf = c Nc.sc.dc.ic
c) q nf = Nc.sc.dc
d) q nf = sc.dc.ic

Answer: b
Explanation: The net ultimate bearing capacity after construction on fairly saturated homogeneous cohesive soils can be calculated from the expression:
q nf = c Nc.sc.dc.ic
where, Nc = 5.14

9. The value of c in the equation, q nf = c Nc.sc.dc.ic used for finding bearing capacity of cohesive soil can be calculated by ___________
a) Unconfined compression strength test
b) Static cone penetration test
c) Relative density test
d) All of the mentioned

Answer: a
Explanation: The value of cohesion c can be obtained from unconfined compression strength test. Alternatively, cohesion c may be determined by static cone resistance q c using the empirical relation between q c and c.

10. The plate load test is essentially a ___________
a) Laboratory test
b) Field test
c) Graphical method analysis
d) None of the mentioned

Answer: b
Explanation: Plate load test is a field test to determine the ultimate bearing capacity of the soil, and the probable settlement under a given loading.