Progressive failure mechanism and stability for a rockslide with a toe rock bridge

Toe rock bridge is a key block for controlling failure mode and overall stability of a rockslide. In this paper, 3D Fast Lagrangian Analysis Code (FLAC3D) is used to simulate the progressive failure process of a simple translational rockslide and a compound rockslide (an engineering case), both of which are assumed to have a toe rock bridge. A range of strain, stress, and plastic zone in the sliding block or on the failure surface were analyzed in the progressive failure process. Based on the concept of the Prandtl failure, this paper proposed a limit equilibrium method considering the Prandtl wedge damage (LEM-PW) for the rockslide with toe rock bridge. Moreover, the influence of the size and position of the Prandtl wedge on the overall stability of the rockslide was discussed. The results show that the combination of the 3D finite difference numerical simulation and the limit equilibrium method can interpret the displacement accumulation at the rear of the rockslide, the stress concentration characteristics of the toe rock bridge, and the variation trend of the landslide stability after the Prandtl wedge damage.