Correct Answer : Rocky ground
Explanation : Tunneling has been classified based on the type of strata present. It includes firm ground, soft ground and running ground. These will determine the bearing capacity of the soil.
Correct Answer : Option (D) : 2N + 2
Correct Answer : Option (A) : Fire-setting
Explanation : Blasting is the conventional method which is adopted in case of rock tunneling. In the case of fire-setting, tunnel is heated with fire and then cooled with water. Rapid expansion and contraction weakens and rock and tends to break.
Correct Answer : Option (C) : Marking profile
Explanation : Rocky strata involve usage of blasting method for developing tunnels. The sequence contains marking profile, loading explosive, removing foul gases, checking, scaling, mucking and bolting.