Pile Foundations MCQ with answer and solution

Concept

Compaction piles are driven into loose granular soil to increase its density and bearing capacity.

Step-by-step solution

1. Recall how piles are classified by function. 2. Friction piles carry load by skin friction. 3. End bearing piles carry load through the tip resting on a hard stratum. 4. Tension piles resist uplift. 5. Compaction piles densify loose sand. So the answer is B.

Explanation

When piles are driven into loose sand, they push the soil sideways and make it dense. These piles are called compaction piles. They improve the bearing capacity of the soil, and they need not carry the load themselves.

Why the other options are wrong

A: Friction piles transfer load by skin friction; they are not used for compaction. C: End bearing piles transfer load to a hard layer at the tip. D: Tension piles resist uplift forces.

Shortcut

The name tells the use: compaction pile = compacts the soil.

Common mistake

Choosing friction piles, because they are also used in granular soil.