62.
American method of tunnelling
(i) Is suitable for large sized tunnels
(ii) Is not suitable for railway or highway tunnels
(iii) Requires heavy timbers

65.
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

66.
Assertion A: English method of tunnelling requires more time as compared to other methods of tunnelling.
Reason R: In English method of tunnelling, the masons and excavators have to work alternately
Select your answer

68.
The following tunnels were constructed in different countries for different purposes:
1.Emperor Claudius built the first Roman tunnel
2.The first highway tunnel was constructed in Hungary
3.The first underground railway tunnel was constructed in Great Britain
4.The first navigational tunnel was constructed in France.
The correct chronological development of these tunnels is:

69.
Pick up the correct statement from the following during tunnel excavation,