Numerical investigation of dynamic response and rupture properties of rock slopes subjected to earthquake triggering.

Landslides triggered by seismic activity have led to substantial human and economic losses. Nevertheless, the fundamental physical mechanisms underlying the vibration and rupture of rock slopes during earthquakes remain poorly understood. In this study, finite element method-based numerical simulations were conducted based on the rock slope at Dagangshan Hydropower Station in Sichuan province, China. Firstly, systematic analysis in both the time and frequency domains were performed to examine the seismic dynamic characteristics of the slope. Subsequently, the transfer function method and the multiple stepwise linear regression method were employed to clarify the underlying mechanism and determine critical factors influencing the slope instability during earthquakes. Time-domain analysis reveals that rock slope dynamic response exhibits notable elevation, surface, and local amplification effects. Specifically, the Peak Ground Acceleration (PGA) amplification coefficient (M_PGA) is significantly higher at elevated locations, near the slope surface and in areas with protrusions. Moreover, the existence of fracture zones and anti-shear galleries minimally influences the dynamic responses but considerably affect the rupture. Specifically, fracture zones exacerbate rupture, while anti-shear galleries mitigate it. Frequency-domain analysis indicates that the dynamic responses of the slope are closely correlated with the degree of slope rupture. As earthquake magnitude increases, the rupture degree of the slope intensifies, and the dominant frequency of the response within the slope decreases, e.g., its value shifts from 3.63 to 2.75 Hz at measurement point 9 near the slope surface. The transfer function of rock slope, calculated under the excitation of wide flat spectrum white noise can reflect the interrelationships between the inherent properties and the rupture degree. Notably, the peak of the transfer function undergoes inversion as the degree of rupture increases. Furthermore, through multiple stepwise linear regression analysis, four key factors influencing the surface dynamic response of the slope were identified: rock strength, slope angle, elevation, and seismic dominant frequency. These findings provide valuable insights into the underlying mechanisms of rock slope dynamic responses triggered by earthquakes, offering essential guidance for understanding and mitigating seismic impacts on rock slopes. [ABSTRACT FROM AUTHOR]