Analytical Approach of the Tunnel Face Effect on the Rock-Support Interface in Viscoelastic Rock Mass

This paper is devoted to an analytical approach of the supported tunnel calculation taking into account the tunnel face effect. This is simulated by a two dimensional study assuming the hypothesis of gradual decompression of the primary stress on the outline of the tunnel. The analytical approach is based on the determination and integration of the rock-lining interface differential equation for viscoelastic rock mass. The author extends the solution for taking into account the tunnel face proximity. A comparison between the analysis without the face influence and the analysis with the face influence is presented and a more economical lining design can be predicted in the framework of the last case. The comparison of the analytical solution with numerical results is performed and a good agreement is obtained.