Face Stability Analysis for a Shield-Driven Tunnel in Anisotropic and Nonhomogeneous Soils by the Kinematical Approach

Abstract

The stability on a tunnel face is of great practical significance for safe construction in tunnel engineering. In this work, an advanced three-dimensional (3D) failure mechanism is extended to the face stability analysis of a tunnel driven in anisotropic and nonhomogeneous soils using the kinematic approach of limit analysis. The results obtained from the presented approach are in good agreement with the existing ones, showing that this method can be further applied to the proposed situation in this paper. Two common examples of cohesion variation, a linear variation with depth and a layered soil, are then analyzed. The numerical results show that both anisotropy and nonhomogeneity have a significant impact on the critical face pressure, especially when the cohesion is relatively large or when there is a weaker layer. Therefore, these two factors should be taken into account in tunnel design.