ANALYTICAL ASSESSMENT OF TUNNEL FACE STABILITY

Abstract

In order to assess the tunnel face stability and to estimate the ground settlements near the face quantitatively, a dynamic analysis has been conducted by taking the continuous and discontinuous mechanisms of the ground into account. The excavation process of the tunnel face, which gives big influence on the face stability, is taken into account in the analysis. The safety assessment equation, which has been proposed by one of the authors and verified through several field data, supports the appropriateness of the stability assessment results obtained by the analysis. The effects of pipe roof to stabilize the face and to decrease the settlements of the ground surface are made clear.