Numerical simulation of seismic dynamic load effect of fault slope

Slope stability on both sides of seismogenic fault under seismic loading has been the focus of academic study. We mainly discuss the seismic effect of dynamic loading on slopes at different positions in this paper. First, we conduct a two-dimensional dynamic finite-element model of spade shaped fault with the size of 500 km×100 km. The symmetrical slopes on both sides of the fault are considered as the landslide terrain. Then, to simulate the earthquake effect, we set a pulse source at the depth of 14 km. The impact of seismic wave propagation on slopes with distance 1 km, 30 km, and 100 km from the fault is analyzed in the first 100 s after earthquake happens. The results demonstrated that the vibration intensity decays rapidly with distance from the source, and that the decay rate at hanging side is more moderate than that of the footwall. With the same distance from the fault, the vibration amplitude of hanging side is larger than the footwall. In different locations of the same surface bulge, vibration amplitude decays with distance from the fault in horizontally. The vibration amplitude in vertical direction is similar to that of the same elevation position. The location with higher elevation has a relatively smaller amplitude. As the distance from the fault increases, amplitudes of surface bulge in horizontal and vertical direction become smaller gradually. The results show that in a place far away from the source, the amplitude of the point is much smaller than the near one which means at where the vibration intensity is larger. With the same geological setting, the near fault hanging side is easier to have landslide.