Numerical investigation on slope stability influenced by seismic load and discontinuity with a continuous-discontinuous method

This study aims to assess the influence of both discontinuities and seismic ground motions on the failure process of an artificially excavated slope in Ya'an, Sichuan, China. The geological background of this area is presented first, based on which a novel continuous-discontinuous method, combining the finite element method and discrete element method (FDEM), is adopted to simulate the dynamic response and failure mechanism of the slope due to its entire process of seismic loads. A well-matched simulation of a series of laboratory tests, with the specimens extracted from excavted slope locations, is conducted to provide reliable simulation parameters. The progressive failure process and its subsequent sliding process of the slope are retrieved with FDEM. By comparing the results with the varying peak accelerations of seismic loads, it is found that cracks of the slope are developed with increasing seismic ground motion which will increase the possibility of initiation of the slope. In the numerical simulation, the effect of discontinuities can be investigated simultaneously with the comparison of two sides of the slopes, as the left side is intact and the right side possesses a discontinuity, through which it demonstrates that the slope with a discontinuity is more vulnerable to instability and experiences a different failure mechanism. This finding will provide a perspective on the whole process and mechanism of landslide failure of slopes with or without discontinuities, which thus can offer guidance for engineering construction and design of excavated slopes in the seismic area in southwestern China.