Methods of Tunneling - IES Previous Year Questions
1. In “full face” method of constructing tunnel, the first operation relates to _____ .
[IES 1996]
- Excavation of one drift in the centre
- Removal of top portion
- Excavation being done along the perimeter
- Removal of bottom portion
Explanation:
In “full face” method, the whole section of the tunnel is excavated at the same time. It is suitable for tunnels of small cross-sectional area (upto 3 m diameter).
2. Which one of the following is considered to be an advantage of the heading and benching method of tunnel construction ?
[IES 1997]
- In this method, it is easy to install timber support.
- Tunneling can be continuous and the work can be expedited.
- In case of excessive water, it is easy to take corrective steps.
- It is suitable for construction in unstable rocks.
Explanation:
Heading and bench method is suitable if the tunnel section is very large and the bedrock is soft and unstable. Simultaneous drilling and mucking is possible in this method.
3. Which one of the following is a component of a shield for tunneling ?
[IES 1999]
- Trench jack
- Stiffener
- Cutting edge
- Liner plate
Explanation:
The main components of a shield used for tunneling are
- The skin
- Cutting edge - It has chisel-shaped cutting teeth with which it grinds the hard rock of tunnel face into soil.
- Propelling jack
- Port holes
- The tail
- The hood
4. Which one of the following methods of tunneling is used in hard rock ?
[IES 2000]
- Needle beam method
- Heading and benching method
- Shield tunneling method
- Forepoling method
Explanation:
Methods of tunneling in rocks are
- Full face method
- Heading and benching method
- Drift method
- Pilot tunnel method
- Perimeter method
5. With reference to tunneling, which of the following factors are to be considered for deciding the size of the shaft ?
- System used for hoisting
- Size of the muck car
- Quantity of muck to be lifted
- Eventual use of the shaft
Select the correct answer using the codes given below:
[IES 2001]
- 1 and 4
- 2, 3 and 4
- 1, 2, 3 and 4
- 1, 2 and 3
Explanation:
The size of the shaft depends on
- Hoisting system
- Vehicle of transport
- Quantity of muck to be lifted
- Eventual use of shaft
- Number of labourers required for tunneling
- Ventilation
- Space required to carry pipes and wires
6. Which one of these methods of tunnel construction is not suitable in rocks ?
[IES 2002]
- Compressed air method
- Heading and benching method
- Drift method
- Full face method
Explanation:
Methods of tunneling in rocks are
- Full face method
- Heading and benching method
- Drift method
- Pilot tunnel method
- Perimeter method
7. Match List-I (Tunnel construction methods) with List-II (Advantages) and select the correct answer using the codes given below the lists:
List-I
- Full face method
- Heading and benching method
- Drift method
- Compressed air method
List-II
- Helps in ventilation of tunnel
- Useful in soft and water-bearing soil
- Simultaneous drilling and mucking is possible
- Tunneling is continuous
[IES 2003]
Codes: A B C D
- 3 4 1 2
- 4 3 1 2
- 3 4 2 1
- 4 3 2 1
Explanation:
- In “full face” method, the whole section of the tunnel is excavated at the same time. It is suitable for tunnels of small cross-sectional area (upto 3 m diameter). Tunneling is done continuously.
- Heading and bench method is suitable if the tunnel section is very large and the bedrock is soft and unstable. Simultaneous drilling and mucking is possible in this method.
- In drift method, tunneling is carried out first in smaller section of the proposed tunnel and then it is widened. It helps in ventilation of the tunnel.
- Compressed air method is useful in soft and water bearing soil.
8. Match List-I (Method) with List-II (Suitability) and select the correct answer using the codes given below the lists:
List-I
- Full face method
- Heading and benching method
- Drift method
- American method
List-II
- For tunneling of large cross-section area through soft ground driving a top drift and then widening the sides
- For rock tunneling carried out first in smaller section of the proposed tunnel and then widened.
- For driving the top portion in advance of the bottom portion for very large tunnel section in unstable rocks.
- For tunneling of small cross-section area in stable rock attacking the whole section at a time.
[IES 2004]
Codes: A B C D
- 4 3 2 1
- 4 1 2 3
- 2 3 4 1
- 2 1 4 3
Explanation:
- In “full face” method, the whole section of the tunnel is excavated at the same time. It is suitable for tunnels of small cross-sectional area (upto 3 m diameter).
- Heading and bench method is suitable if the tunnel section is very large and the bedrock is soft and unstable. Simultaneous drilling and mucking is possible in this method.
- In drift method, tunneling is carried out first in smaller section of the proposed tunnel and then it is widened. It helps in ventilation of the tunnel.
9. Assertion (A): Open cut is economical than tunneling for depths of over burden less than 20 metres.
Reason (R): Heading and Bench method is suitable for tunneling in soft soils.
[IES 2004]
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not a correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Explanation:
Heading and bench method is used for tunneling in rocks.
10. Consider the following statements with respect to tunneling methods:
- Full face excavation is suitable for small size tunnel of short length in competent rock. It is not suitable in urban areas.
- Heading and benching method is suitable for soft rock tunneling of medium size.
- Drift method is suitable for large tunnels in difficult or incompetent rock.
Which of these statements are correct ?
[IES 2005]
- 1, 2 and 3
- 2 and 3
- 1 and 2
- 1 and 3
Explanation:
Drift method is not suitable for large tunnels and difficult rocks.