Engineering Questions with Answers - Multiple Choice Questions

# Group Action in Piles

1 - Question

The efficiency of pile group depends upon __________
a) Characteristic of pile and Spacing of pile
b) Bearing capacity of soil
c) All of the mentioned
d) None of the mentioned

Explanation: The efficiency of pile group depends upon the following factors: Characteristics of pile (i.e. length, diameter, material etc.), spacing of pile, total number of piles in a row and number of rows etc.

2 - Question

Which of the following formulae can be used for determining the efficiency of pile group?
a) Dynamic formulae
b) Static formulae
c) Feld’s formulae
d) Hiley’s formulae

Explanation: Converse Labarre formulae, Seiler-kenney formulae, Feld’s rule are some of the common formulae available for determining the efficiency of pile group.

3 - Question

In which of the following rule, the value of each pile is reduced by one-sixteenth?
a) Converse Labarre formulae
b) Feld’s formulae
c) Seiler-Keeney formulae
d) All of the mentioned

Explanation: According to Feld’s rule, the value of each pile is reduced by one-sixteenth on account of the effect of the nearest pile in each diagonal or straight row of which the pile in question is a member.

4 - Question

The bearing capacity of a single pile in clay is mainly due to _________
a) Friction
b) Shear strength of soil

Explanation: The bearing capacity of single pile in clay is mainly due to friction, and the friction and the point bearing resistance may be negligible.

5 - Question

The downward drag acting on a pile due to the movement of the surrounding is called ________
a) Skin friction
b) Negative skin friction
c) Frictional force
d) None of the mentioned

Explanation: Negative skin friction is downward drag acting on a pile due to the downward movement of the surrounding compressible soil relative to the pile.

6 - Question

The area of the pile group along the failure surface is equal to __________
a) Perimeter × Area of cross section
c) Perimeter × Length
d) Perimeter/area of cross section

Explanation: The area of the pile group, along failure surface is approximately equal to the perimeter P of the pile group multiplied by the length L of the pile.

7 - Question

The pile spacing of each pile is taken as __________ diameter of the pile.
a) Four
b) Five
c) Three
d) Ten

Explanation: A spacing of three times the diameter of piles is commonly selected as trial spacing between the piles and checked against the criterion that the resistance Qs obtained.

8 - Question

The settlement of a group of friction piles can be computed on the assumption that ________
a) Clay is incompressible
b) Pile below the lower level is ignored
c) Bearing resistance is zero
d) None of the mentioned.

Explanation: As a rough approximation, the settlement of a group of friction piles can be computed on the assumptions that the clay contained between the top of piles is incompressible.

9 - Question

The equation used for determining the bearing capacity of a group of friction piles is __________
a) Qup = Rf + Rp
b) Qug = n Qup . ηg
c) Qug = n Qup / ηg
d) None of the mentioned