Quantitative risk analysis of toppling slope considering seismic risk

Abstract

Risk analysis and assessment are important tools to solve the inherent uncertainty of slopes. At present, there are few studies on systematic quantitative risk analysis of slopes considering the uncertainty of external load and internal geotechnical mechanical parameters at the same time. This paper takes the toppling slopebehind the power plant of the Zhala hydropower station in Tibet as an example. Based on the probability density function (PDF) of site seismic peak acceleration and the fitting function of slope failure probability under different seismic peak accelerations, the overall slope failure probability is calculated by numerical integration, and the influence range of the slope is simulated by the discrete element method (DEM). Then, vulnerability analysis and quantitative risk calculation of elements at risk are carried out. Finally, the ALARP criterion is used for risk assessment. The results show that, considering the seismic risk, the failure probability of the slope is 0.061 9 in the 50-year design reference period. The slope poses a great threat to the ground powerhouse of hydropower stations, and the corresponding economic risk is 54.82 million RMB. According to the ALARP criterion, the slope risk is in the unacceptable area, and measures should be taken to prevent or avoid the risk. The research results have guiding significance for decision-making and risk management of slope treatment engineering.

Keywords

• seismic risk
• toppling slope
• instability probability
• vulnerability
• quantitative risk analysis