Consider the following statements regarding tunnel : 1. In hills with soft rocks, a tunnel is cheaper than a cutting. 2. The maintenance cost of a tunnel is considerably higher than that of a bridge. 3. The construction of a tunnel is costly as it requires special construction. Which of the above statements are correct ?
- A1 and 2 only
- B2 and 3 onlyCorrect
- C1 and 3 only
- D1, 2 and 3
Solution
Concept
Economics of tunnels
Step-by-step solution
1. In soft rock a cutting is cheaper than a tunnel (tunnels are economical in hard rock on hilly terrain) (statement 1 false). 2. Tunnels need lighting, ventilation, drainage and lining maintenance, so their upkeep costs more than for a bridge (true). 3. Tunnel construction needs special equipment and techniques, which is costly (true).
Explanation
Tunnels are justified only where a cutting would be very deep or in hard rock.
Why the other options are wrong
Statement 1 is false for soft rock.
Shortcut
Tunnel: costly to build and maintain.
Correct answer: B) 2 and 3 only