Statement (I): During pile driving, heads, helmets or caps are placed on the top of the pile to receive the blows of the hammer and to prevent damage to the head of the pile. Statement (II): Piles are ordinarily driven to a resistance measured by the number of blows required for the last 5 cm of penetration.
- ABoth Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
- BBoth Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)Correct
- CStatement (I) is true but Statement (II) is false
- DStatement (I) is false but Statement (II) is true
Solution
Concept
Pile driving practice
Step-by-step solution
1. A pile cap or helmet cushions the hammer blow and protects the pile head (Statement I true). 2. Driving is continued until the penetration per blow (or blows per last 5 cm) reaches the specified set (Statement II true). 3. The two statements describe different aspects of pile driving, so II does not explain I.
Explanation
Both are correct practices of pile driving, but one concerns protection of the pile head and the other concerns the termination criterion.
Why the other options are wrong
II is not an explanation of why caps are used.
Shortcut
Cap = protect head; set = stop criterion.
Common mistake
Choosing (a).
Correct answer: B) Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)