Tunnelling - Engineering

Q1:

Which one of the following statements is not correct with regard to heading and hench-ing 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 After driving the top portion 3 m to 3.5 m holes are drilled into the head and bench.

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

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

ANS:E - Firing of head holes is done just before the bench holes are fired.

No answer description is available.