Face stability analysis for a shield-driven tunnel with non-linear yield criterion

Abstract

The aim of this work was to investigate the face stability of a tunnel driven by a pressurised shield for cases of collapse failure and blow-out failure based on the kinematic approach of limit analysis. For the analyses, the soil material was assumed to follow the non-linear Mohr–Coulomb failure criterion. Advanced rotational failure mechanisms were applied to the face stability analysis. The numerical results, optimised using Matlab, were close to the existing solutions, proving that this approach is reliable. The influences of two parameters (the tunnel buried depth C and the initial cohesion co) on the critical support pressures and the shapes of the failure mechanisms for collapse failure and blow-out failure were investigated. The results of the collapse failure and blow-out failure showed that the critical support pressures and the shapes of failure mechanisms were significantly influenced by these parameters and the non-linear failure criterion should be considered in practice to improve the accuracy of the critical support pressures.