Numerical analysis on the influence of topographic effect for rock slope seismic response under oblique incidence of P waves

The seismic waves do not arrive with a vertical incidence for near-fault rock slopes, which highlights the importance of investigating the topographic effect under oblique incidence seismic waves. The equivalent nodal force method was employed to simulate seismic P waves with oblique incidence, by utilizing the finite difference method and viscoelastic artificial boundary. The accuracy of the method was verified by comparing it with the analytical solution of the free field in half-space, and the error is within 5%. Furthermore, the influence of slope heights, angles, and shapes on the dynamic response of rock slopes is analysed under the different incidence angles of seismic waves. The results show that the critical height of the rock slope varies with the incident angle, and the greater the incidence angle, the lower the critical height of the slope. The maximum value of the acceleration amplification coefficient is 8.5 in the slope shoulder when both the slope angle and incident angle are 75°. Additionally, the location of the strong acceleration response area of the concave and linear slopes is almost not affected by the incident angle, whereas the convex slopes move from the slope shoulder towards the convex position with increasing incident angle.