Question

A tunnel with vertical walls and arched crown is constructed through a set of sedimentary beds. The thickness of individual beds is significantly less than the wall-height of the tunnel. For which of the following conditions, one of the tunnel walls becomes unstable?

• A. The tunnel axis is horizontal and the beds are horizontal
• B. The tunnel axis is parallel to the strike of beds and the beds dip 45⁰ – 60⁰
• C. The tunnel axis is parallel to the strike of beds and the beds are vertical
• D. The tunnel axis is perpendicular to the strike of beds and the beds are vertical

Answer 1

Answer: (B)

The tunnel axis is parallel to the strike of beds and the beds dip 45⁰ – 60⁰

Answer 2

The Correct answer is (B): The tunnel axis is parallel to the strike of beds and the beds dip 45⁰ – 60⁰The tunnel axis is parallel to the strike of beds and the beds dip 45⁰ – 60⁰