Stability evaluation of proposed traffic tunnel No. 3 at Al-Dela descent, Asir province, Saudi Arabia

الملخص EN

TWO methods, namely stereographic projection and vector analysis, have been adopted herein to investigate the stability conditions along the proposed route of traffic tunnel No.

3.

This tunnel is planned to be driven through foliated slate and chlorite-schist intercalated by metabasaltic rock.

The structural features in the studied area are mainly joints of two major and one minor sets, besides the cleavage and schistosity.

The study concluded that free falling from the tunnel roof and sliding of blocks in the north- western sidewall will take place along most of the tunnel length.

Rock bolts are the most suit- able support system for the unstable blocks.