Investigation on dynamic response characteristics of a complex rock mass slope at a tunnel entrance under strong earthquake using continuous-discontinuous element method

Abstract

Earthquake-induced landslide at the tunnel entrance is one of the important geological hazards during tunnel construction and operation. In order to investigate the dynamic response characteristics of a layered rock mass slope at the tunnel entrance subject to strong earthquake excitation, the continuous-discontinuous element method (CDEM) was used to conduct two-dimensional dynamic analyses on a rock slope with weak interlayers at a tunnel entrance along the Sichuan-Tibet region in western China. The seismic dynamic response characteristics of the slope are analyzed by analyzing the seismic wave characteristics and dynamic acceleration response characteristics. The numerical results show that the characteristics of seismic wave inside the slope and at the slope surface under strong earthquake are compared, and the waveform characteristics at the slope surface are more complicated than that inside the slope body. By analyzing the peak ground acceleration inside and outside the slope body, the dynamic amplification effect of the slope is investigated. The acceleration amplification effect inside the slope and at the slope surface is compared and analyzed under strong earthquake. Under the same condition, the dynamic acceleration amplification effect of the slope surface is larger than that of the internal slope. In addition, the seismic dynamic failure mode of the slope is investigated by analyzing acceleration distribution nephogram under strong earthquake. The research results are of great significance for further understanding the seismic failure mechanism of layered rock landslides at the tunnel entrance.