Drift method of tunnelling is used to construct tunnels in
- ABroken grounds
- BSoft grounds
- CPlane grounds
- DRockCorrect
Solution
Concept
Drift method
Step-by-step solution
1. The drift method is used in rock.
Explanation
A small tunnel is driven first and then enlarged.
Why the other options are wrong
Others are not suited.
Shortcut
Drift = rock.
Correct answer: D) Rock