Foundation Engineering Questions and Answers Part-11

1. Positive projecting conduits are of ___________ types.
a) 2
b) 5
c) 3
d) 4

Answer: d
Explanation: Positive projecting conduits are of four types:
i) complete ditch conditions
ii) complete projection conduits
iii) incomplete ditch conduit
iv) incomplete projection conduits.

2. The settlement ratio for a negative projecting conduit is __________
a) Always positive
b) Always negative
c) Negative in some cases
d) None of the mentioned

Answer: b
Explanation: The settlement ratio for negative projecting conduits is always negative since the settlement of the critical plane is more than the settlement of the natural ground.

3. The magnitude and direction of relative movements between the interior and exterior prisms of the conduits are dependent upon the ___________
a) Settlement ratio
b) Projection ratio
c) Settlement of conduits
d) Compressive strain

Answer: a
Explanation: The magnitude and direction of relative movements are dependent upon the settlement ration rsd defined by the equation:
rsd = (sm + sg) – (sf + dc)/sm.

4. Critical plane in conduit is located at ___________
a) Tangential to the top of the conduit
b) Tangential to the bottom of the conduit
c) Centre of the conduit
d) All of the mentioned

Answer: a
Explanation: The critical plane is a horizontal plane, located tangential to the top of the conduit

5. If the critical plane settles more than the top of the conduit, the settlement ratio is __________
a) Zero
b) Negative
c) Positive
d) Unity

Answer: c
Explanation: If the critical plane settles more than the top of the conduit i.e. if (sm + sg) is more than (sf + dc) the settlement ratio is positive.

6. Both the projection condition and the ditch conditions of a positive projecting conduit may be __________
a) Complete
b) Incomplete
c) All of the mentioned
d) None of the mentioned

Answer: c
Explanation: Depending upon the position of plane of equal settlement, both the projection conditions and the ditch conditions of a positive projecting conduit may be complete or incomplete.

7. If the plane of settlement does not fall within the embankment, then such a condition is called _________
a) Complete ditch condition and Complete project condition
b) Incomplete ditch condition
c) None of the mentioned
d) All of the mentioned

Answer: a
Explanation: If the embankment is not of sufficient height, the plane of equal settlement does not fall within the embankment (i.e., He > H); such a condition is called complete projection condition or complete ditch condition.

8. The sign used for complete projection is __________
a) +
b) –
c) No sign is used
d) None of the mentioned

Answer: a
Explanation: Since + is used for positive settlement ratio, (+) sign is used for complete projection and (–) sign used for complete ditch condition.

9. The recommended value of settlement ratio for embankment, to use in design is __________
a) +0.5
b) +1.0
c) – 0.3
d) – 0.4

Answer: b
Explanation: The value of rsd for embankment of rigid conduit type is +1.0, which can be used for any ordinary rock hard, hard or unyielding soil as foundation soil.

10. The load on a negative conduit is given by the equation __________
a) Wc = Cn γ Bd
b) Wc = Cn γ Bd2
c) Wc = γ Bd
d) Wc = Cn Bd2

Answer: b
Explanation: The load on the conduit is given as WC = Cn γ Bd2, where Cn= load coefficient for negative projecting conduit.