Three-Dimensional Static and Seismic Stability Analysis of a Tunnel Face Driven in Weak Rock Masses

Abstract

Face stability is an important issue for tunnel designs and constructions. This study investigated the seismic face stability of tunnels drilling in heavily fractured rock masses that follow the generalized Hoek–Brown yield criterion by means of an advanced three-dimensional (3D) failure mechanism in the framework of the kinematic approach of limit analysis. The pseudostatic method was employed to model seismic loadings. The classical tangential technique was used to compute the upper-bound solutions of necessary face pressures in the context of the generalized Hoek–Brown criterion. The obtained critical face pressures were found to agree well with those predicted by 3D numerical simulations using a commercial program and improve the existing upper-bound solutions previously published in the literature. Four sets of normalized charts are provided for parametric analysis and practical application in the preliminary design phase of tunnel face stability.