Which one of the following is considered to be an advantage of the heading and benching method of tunnel construction?
A. It is suitable for construction in unstable rocks
B. In this method, it is easy to install timber support
C. Tunnelling can be continuous and the work can be expedited
D. In case of excessive water, it is easy to take correct steps
A good blast with a good yield is obtained if the cut hole is___________________?
A. normal to face
B. inclined at 45° to the face
C. inclined at 15° to the face
D. inclined at 30° to the face
Drifters can be used to drill_________________?
A. only up holes
B. only down holes
C. horizontal or up holes
D. horizor„al, down or up holes
A. wagon drill, churn drill, shot drill
B. wagon drill, shot drill, churn drill
C. shot drill, churn drill, wagon drill
D. churn drill, wagon drill, shot drill
In compressed air tunneling, the volume of free air provided is______________?
A. 6 mJ per second per m2 of face area
B. 6 m3 per minute per m2 of face area
C. 20 m3 per minute per m2 of face area
D. 6 m3 per hour per m2 of face area
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