Which one of the following statements is not correct for heading and benching method of tunnelling?

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

Tunneling can be continuous and the work can be expedited

D

In case of excessive water, it is easy to take correct steps

Which one of the following statements is not correct with regard to heading and henching method of tunnelling?

A

Driving of tunnel is done in two portions of its section

B

Driving the top portion is done in advance of the bottom portion

C

The holes in head and bench are loaded together with explosive for blasting

D

Firing of head holes is done just before the bench holes are fired

The length of the needle beam used in needle beam method of tunnelling is usually

A

2 m to 4 m

B

2.5 m to 6 m

C

4 m to 7 m

D

5 m to 6 m

In Belgium method of tunnelling

A

Construction of side walls is completed before invert and roof arch are built

B

Construction of roof arch is completed before side walls and inverts are built

C

Construction of invert is completed before side walls and roof arch are built

D

Construction of invert and side walls is completed before roof arch is built

Forepoling method is generally adopted for tunnelling in:

A

Soft ground

B

Firm ground

C

Running ground

D

None of these

Which one of the following methods of tunnelling does not require the use of time bearing?

A

Linear plate method

B

Shield method

C

Compressed air method

D

All of these

Which one of the following methods is generally adopted for tunnelling in firm ground

A

Full face method

B

Top heading and benching method

C

Drift method

D

All the above

Pick up the explosive used for tunnelling in soft rocks from the following:

A

Blasting gelatine

B

Special gelatine

C

Ammonia dynamite

D

Semi-gelatine

The most suitable soil for compressed air tunnelling is

A

Silt

B

Sand

C

Clay

D

Gravel

In compressed air tunnelling, the volume of free air provided is

A

6 m³ 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 one of the following statements is not correct for heading and benching method of tunnelling?

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