Question 61. In the given figure drill holes, heading, mucking and benching are numbered as 1, 2, 3, 4; The correct sequence is:

Question 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

Question 63. If ‘D’ is the diameter of tunnel in meters, then the thickness of lining in mm, as per the empirical formula is given by

Question 64. As compared to a single free face, if a charge of explosive is placed equidistant from two faces, then the yield

Question 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 liningSelect your answer based on the coding system given below:

Question 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 alternatelySelect your answer based on the coding system given below:

Question 67. Drift method of tunneling is used to construct tunnels in

Question 68. The following tunnels were constructed in different countries for different purposes: 1.Emperor Claudius built the first Roman tunnel2.The first highway tunnel was constructed in Hungary3.The first underground railway tunnel was constructed in Great Britain4.The first navigational tunnel was constructed in France.The correct chronological development of these tunnels is:

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

Question 70. In case of drift method of tunnelling, the drift may be excavated at