Abstract

In order to further reveal the failure mode and dynamic response law of dangerous rocks with different degree of weathering in the rock cavity under the action of earthquake and to provide early warning and forecast for steep slope of dangerous rocks in similar earthquake areas, a typical steep slope of dangerous rock in earthquake area of Sichuan, China, was taken as the research object, after detailed geological survey, and according to the chain development law of dangerous rock, the steep slope of dangerous rock before the earthquake was restored. Based on the 3D particle flow software PFC3D, the dangerous rock was divided into 3 modes according to the degree of weathering of the mudstone rock cavity, and the three-dimensional discrete element dangerous rock model under different modes was established. By introducing the horizontal and vertical two-way coupled seismic waves in Wenchuan, Sichuan, in 2008, the failure evolution process of steep slope of dangerous rock under the action of the horizontal and vertical coupled seismic waves was dynamically simulated, which proved the rationality of the simulation. The frequency spectrum of velocity-time history signal of each rock block in the dangerous rock model was analyzed by MATLAB programming, and the time-frequency characteristics of each dangerous rock model under the action of coupled seismic wave were studied. The research results have important scientific guiding significance and practical value for the dynamic stability evaluation and prediction of such steep slope of dangerous rocks under the combined action of rock cavity weathering and earthquake.

Highlights

  • Sichuan Province, China, is located in the Helan MountainLiupan Mountain-Longmen Mountain-Hengduan Mountain seismic zone, where earthquake disasters occur frequently

  • As one of the most important secondary geological disasters in the earthquake area, examples of rock slope instability induced by earthquake are common, often causing huge economic and property losses. e dangerous rock steep slope is the main carrier of seismic slope instability disaster, because the rock mass is cut by different structural planes, when the main control structural plane at the rear of the dangerous rock block gradually penetrates until it breaks under the action of multiple factors, instability and destruction of dangerous rocks will occur

  • The peak velocity and PGA magnification coefficient of the rock particles monitoring points of A and B chains are shown as the rule of the maximum in Model 3, the second in Model 2, and the minimum in Model 1, indicating that the seismic dynamic response of rock particles is positively correlated with the weathering depth of the rock cavity

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Summary

Introduction

Sichuan Province, China, is located in the Helan MountainLiupan Mountain-Longmen Mountain-Hengduan Mountain seismic zone, where earthquake disasters occur frequently. This paper takes the dangerous rock slope of rock cavity type in Sichuan Province, China, as the research object, the combined conditions of rock weathering and seismic action were considered, discrete element particle flow software (PFC3D) was used to simulate the dynamic failure process, the dynamic response rule and failure mechanism under the action of earthquake were revealed, and the energy distribution and frequency characteristics were discussed. It is of great scientific significance and practical value to evaluate and forecast the dynamic stability of the dangerous rock slope under the combined action of rock cavity weathering and earthquake

Establishment of Dangerous Rock Model
Establishment of Numerical Model
Failure Mode and Dynamic Response of Rock Vibration
B2 B3 B4
Model 3
Mic2rochain 3sequence
10 A1 A2 A3 A4 B1 B2 B3 B4
Findings
Conclusions
Full Text
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