Plan
The tunnel is planned to pass through the hillock of the university. The alignment has been fixed such that it avoids any above-ground buildings as shown in the plan map of the tunnel.
ERT survey along the alignment of the tunnel revealed weathered and highly weathered metasandstone.
Upon close inspection of the survey and geological investigation, the rock mass was found to be of very poor quality according to the rock quality index classification. For the efficient and optimum design of tunnel support, the entire rock mass of the region was categorized into four different classes, and support combinations were defined accordingly. The four classes of rocks (I, II, III, IV) along the alignment and the location of the cavern is shown in the figure below.
The location of the cavern has been identified considering the rock strength, its stability against potential failure, and the overall stability of the slope.