Question

Directions : The following items consists of two statements; one labelled as 'Assertion (A)' and the other as 'Reason (R)'. You are to examine these two statements carefully and select the answers to these items using the codes given below :

Codes:

Assertion (A) : Negative skin friction will act on piles in filled up soil, which should be considered in design of pile foundations.
Reason(R) : The filled up soils start consolidating and develop a drag force on the pile.

• A. both A are R are true and R is the correct explanation of A
• B. both A and R true but R is not a correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer 1

The correct option is A both A are R are true and R is the correct explanation of A

When the rate of consolidation of filled up soil or weak soil is more than the rate of settlement of pile, a downward drag force acts on the pile. This is called negative skin friction and reduces load carrying capacity of pile. It should be considered in the design of pile foundation.