Pick up the correct statement regarding drilling a tunnel from the following:
A. Holes are drilled by pneumatically operated rock drills
B. One drill is required for each 4 to 5 m2 force area
C. The diameter of the bore hole at the deepest point should be 6 mm more than the diameter of the cartridge
D. All of the above
Answer: Option D
A. (i) and (ii) are correct
B. (iii) and (iv) are correct
C. (i) and (iv) are correct
D. (ii) and (iii) are correct
Which of the following lining material is useful for shield driven tunnels in sub aqueous regions?
A. Stone masonry
B. Timber
C. Cast iron
D. Cement concrete
Which of the following methods of tunneling is used for long tunnels at great depths?
A. Army method
B. Needle beam method
C. Austrian method
D. English method
A. Only up holes
B. Only down holes
C. Horizontal or up holes
D. Horizontal down or up holes
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