Simulating Crack Development and Failure Characteristic of Toppling Rock Slope under Seismic Loading on Lancang River in China

Shiqi Liu,Qingxiang Meng,Long Yan,Huanling Wang,Hao Xiong

doi:10.2113/2021/5424127

Abstract

Abstract Toppling rock slopes, induced by rapid and continuous downcutting of Lancang River, are widely distributed in the mountainous area of southwest China. To investigate the instability mechanism of 1# toppling rock slope of Huangdeng Hydropower Station under seismic loading, particle flow code (PFC) is applied to simulate the dynamic response and failure mode. The study considers the particle characteristics of displacement, velocity, energy, and cracks. According to numerical results, the potential failure mechanism of toppling rock slope is identified: multisliding surfaces form at the interfaces between the highly and moderately toppled rock mass and between the highly/moderately and weak toppled-crept rock mass; intersecting faults cut rock mass at the toe, leading to shear-toppling deformation; tension cracks develop, penetrate, and coalesce in the weak toppled-crept rock mass, resulting in tension-toppling-bending deformation. During the 2 to 5 s of strong seismic intensity, crack increases sharply and energy of particles fluctuates greatly. The impacts of the amplitude of seismic loading and loading method in PFC are investigated. This study will provide a practically useful reference for seismic design of rock slopes.

Highlights

Toppling failure, as one of the most serious and hazardous landslide instability modes of rock slopes and underground caverns, usually occurs in mountainous and canyon areas, which is responsible for property loss and threats the safety of human life [1,2,3]
For earthquake-induced toppling failure and landslides, shaking-table tests and numerical simulations are effective approaches to study the characteristics of seismic wave propagation and dynamical response
Che et al [9] and Song et al [10] studied the influence of wave propagation on the stability of bedding rock slopes and other slopes containing nonpersistent joints through a combined approach using shaking-table test and finite element method (FEM)

Summary

Introduction

As one of the most serious and hazardous landslide instability modes of rock slopes and underground caverns, usually occurs in mountainous and canyon areas, which is responsible for property loss and threats the safety of human life [1,2,3]. For earthquake-induced toppling failure and landslides, shaking-table tests and numerical simulations are effective approaches to study the characteristics of seismic wave propagation and dynamical response. Song et al [7, 8] studied the mechanism of instability of rock slopes with toppling discontinuous antidip joints under seismic loadings, with special attention focused on the relationship between local damage and landslides. Che et al [9] and Song et al [10] studied the influence of wave propagation on the stability of bedding rock slopes and other slopes containing nonpersistent joints through a combined approach using shaking-table test and finite element method (FEM). Discontinuity of wave at joint surfaces due to reflection and transmission was observed, but failure mode of slope was not studied. Other studies have investigated this aspect of wave propagation [11, 12]

Results

Discussion

Conclusion