Pseudo-static analysis of tunnel face stability using the generalized Hoek-Brown strength criterion

The stability of a tunnel face driven by a pressurized shield is investigated in the light of a limit analysis kinematic approach formulated in the context of the modified Hoek-Brown strength criterion. The analysis focuses on evaluating the destabilizing effects induced by seismic loading. The pseudo-static approach is adopted to account for the effects of inertial forces developed in the rock mass by the passage of seismic waves. Taking advantage of the ability to compute analytically, the expressions of the support functions for the modified Hoek-Brown strength criterion, rigorous limit analysis solutions can be derived semi-analytically for the tunnel face stability. Particular emphasis is given to the description of the Horn failure mechanism and associated lower bound estimates of the limit face supporting pressure. The approach is then applied to investigate the influence of some relevant strength and loading parameters in the tunnel face stability. Copyright (C) 2013 John Wiley & Sons, Ltd.