31. In compressed air tunneling, the volume of free air provided is
- 10 cuft per seconds per sq.ft. of face area
- 10 m3 per min. per m2 of face area
- 20 cuft per min. per sq.ft. of face area
- 6 m3 per hour per m2 of face area
32. For highways, tunneling is preferred if the open cut exceeds
- 15 m depth
- 10 m depth
- 25 m depth
- 20 m depth
33. Which of the following methods is suitable for the construction of large-sized railway or highway tunnels?
- Forepoling method
- American method
- Full face method
- Case method
34. From the economic point of view, tunneling is advisable when the depth of open cut is more than
- 12 m
- 6 m
- 18 m
- 24 m
35. In case of long tunnels, the drainage system consists of sump wells which are located at regular intervals of about
- 100 m to 200 m
- 50 m to 100 m
- 300 m to 500 m
- 200 m to 300 m
36. Which of the following methods is generally considered the most efficient system for ventilation of tunnels?
- Driving a shaft through the tunnel
- Driving a drift through the top portion
- Blow in method
- Combination of blowing and exhausting
37. In order to maintain the desired shape of the tunnel, the cross-section of the tunnel must be checked at a regular interval of
- 4 m to 6 m
- 2 m to 3 m
- 8 m to 15 m
- 5 m to 7 m
38. The following operations are generally employed for the Needle Beam Method of tunneling
- A trench jack is placed on the centre line of the needed beam to support the segment.
- A monkey drift is driven for a short distance.
- Drift is widened sideways and supported by lagging segments.
- The roof of the monkey drift is supported by lagging
- The needle beam is slowly skidded forward into the monkey drift.
The correct sequence of operation is
- i – ii – iii – iv – v
- iii – iv – v – i – ii
- ii – i – v – iv – iii
- ii – iv – v – i – iii
39. For initial surveys of tunnel, the following activities are involved
- Marking portal points with concrete pillars on the ground
- Marking tunnel obligatory points on the topographical maps
- Driving lines between the fixed obligatory points
- Preliminary setting of the tunnel on the topographical survey of Indian maps
The correct sequence of the activities are
- ii, i, iv, iii
- i, ii, iii, iv
- iii, ii, iv, i
- iv, ii, iii, i