Piles are usually driven by:
Try it first: pick an option, then read the explanation.
Asked in SSC JE 27/01/2018 (Morning)
Detailed Explanation
Driven piles are forced into the ground by repeated blows of a hammer guided between the leads of a pile frame (pile driver).
Why “All options are correct” Is Correct
Common hammers are: the drop hammer (a weight lifted and dropped), the single-acting steam/air hammer (steam lifts the ram, gravity drives it down), the double-acting hammer (steam also pushes the ram down), the diesel hammer (combustion lifts the ram and adds energy) and the vibratory hammer. All of the listed options are used, so the answer is (d).
| Hammer | How it works |
|---|---|
| Drop hammer | Weight lifted by winch, falls freely |
| Single-acting | Steam/air lifts the ram; it falls by gravity |
| Double-acting | Steam/air lifts and also pushes the ram down; fast blows |
| Diesel | Fuel explosion lifts the ram and drives the pile |
| Vibratory | Vibrates the pile into loose, saturated granular soil |
Why the Other Options Are Wrong
- A. diesel operated hammer: Correct, but drop and steam hammers are also used.
- B. drop hammer: Correct, but diesel and steam hammers are also used.
- C. single acting steam hammer: Correct, but diesel and drop hammers are also used.
Key Point
Pile hammers: drop, single-acting, double-acting, diesel, vibratory.
Key Concepts for Students
- Vibratory hammers work best in saturated sands.
- Diesel hammers work poorly in very soft soil (too little resistance to fire).
- Bored piles avoid driving vibration near existing buildings.
Practice more: this is question 25 in Shallow and Deep Foundation MCQs – Part 2. Try the whole set and check every answer instantly.