Questions
21
Assertion A : When rock conditions are favorable, it will not be necessary to take up concrete lining concurrently with the driving operations till the full length of the tunnel has been driven through rock.
Reason R : A tunnel through rock, hard or soft, does not need any concrete lining.
Select your answer based on the coding system given below:Answer: A is true but R is false.
22
Which one of the following is a component of a shield for tunnelling ?
Answer: cutting edge
23
In “full face” method of constructing tunnels, the first operation relates to
Answer: excavation being done along the periphery
24
Which one of the following is considered to be an advantage of the heading and benching method of tunnel construction?
Answer: Tunnelling can be continuous and the work can be expedited.
25
Consider the following situations.
1. Soil is soft.
2. Volume of existing surface traffic on the alignment is heavy.
3. Track is at a deeper level.
4. Water table is high.
In the construction of Metro Railways, “Cut and Cover” method of construction is suitable in situations listed atAnswer: 1 and 4
27
What is the correct sequence of the following events in rock tunnelling?
1. marking tunnel profile
2. loading explosives and blasting
3. checking misfire
4. mucking
5. removing foul gas
6. setting up and drilling
7. guniting
Select the correct answer using the codes given below. Codes:Answer: 1,6,2,5,3,4,7
