Which of the following statements is true?
Try it first: pick an option, then read the explanation.
Asked in SSC JE 29/01/2018 (Morning)
Detailed Explanation
A pile is a long, slender column-like member — of timber, concrete or steel — driven, bored or cast into the ground to carry loads to depth.
Why “A pile is a slender member which transfers its load to the surrounding soil” Is Correct
A pile may carry load at its tip, along its shaft, or both. The statement that covers every case is that it transfers its load to the surrounding soil. Options (a) and (c) each describe only one type of pile (end-bearing or friction), and (d) is too narrow. So (b) is the true general statement.
| Pile type | How it works / where it is used |
|---|---|
| End-bearing (point-bearing) pile | Passes through soft soil and rests on a hard stratum; carries load at its tip like a column |
| Friction (floating) pile | No hard stratum within reach; carries load by skin friction along its length |
| Compaction pile | Driven into loose sand to densify it and raise its bearing capacity; not meant to carry load itself |
| Tension (uplift) pile | Resists uplift, e.g. under towers, basements below the water table |
| Batter pile | Driven at an angle to resist inclined or horizontal loads |
| Sheet pile | Forms a wall to retain soil or water; not for vertical load |
Why the Other Options Are Wrong
- A. A pile is a slender member which transfers the load through its lower end onto a strong stratum: Describes only end-bearing piles.
- C. A pile is a slender member which transfers its load by friction: Describes only friction piles.
- D. A pile is a cylindrical body of concrete which transfers the load at a depth greater than its width: Piles can be steel or timber and need not be cylindrical; depth > width defines deep foundations in general, not piles.
Key Point
Pile: slender member transferring load to the surrounding soil by end bearing and/or skin friction.
Key Concepts for Students
- Pile foundations are used for tall buildings, bridges and water tanks on weak soil.
- Tension piles resist uplift; batter piles resist lateral loads.
- Ultimate pile load Q_u = Q_b + Q_s.
Practice more: this is question 45 in Shallow and Deep Foundation MCQs – Part 3. Try the whole set and check every answer instantly.