考虑地震危险性的倾倒变形边坡风险定量分析  

Quantitative risk analysis of toppling slope considering seismic risk

作　　者：魏进兵[1,2] 何治良 杨仲康[1,2] Wei Jinbing;He Zhiliang;Yang Zhongkang(College of Water Resources and Hydropower,Sichuan University,Chengdu 610065,China;State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,China;School of Environment and Resources,Southwest University of Science and Technology,Mianyang Sichuan 621010,China)

机构地区：[1]四川大学水利水电学院,成都610065 [2]四川大学,水力学与山区河流开发保护国家重点实验室,成都610065 [3]西南科技大学环境与资源学院,四川绵阳621010

出　　处：《地质科技通报》2022年第2期71-78,共8页Bulletin of Geological Science and Technology

基　　金：国家重点研发计划项目(2018YFC1505006);国家自然科学基金项目(41977246,51904248)。

摘　　要：风险分析与评估是解决边坡固有不确定性的重要工具,但同时考虑外在荷载和内在岩土力学参数的不确定性,对边坡进行系统定量风险分析的研究较少。以西藏扎拉水电站厂后倾倒变形边坡为例,基于场地地震峰值加速度概率密度函数和不同地震峰值加速度下边坡失稳概率拟合函数,采用数值积分计算了边坡在设计基准期的失稳概率,并采用离散元方法对边坡失稳后的影响范围进行了数值模拟,在此基础上进行了承灾体易损性分析及定量风险计算,最后采用ALARP准则进行了风险评价。研究表明,考虑地震危险性条件下,扎拉水电站厂后倾倒变形边坡在50 a设计基准期内失稳概率为0.0619;边坡对水电站地面厂房存在较大威胁,相应财产风险为5482万元;根据ALARP准则,边坡风险处于不可接受区,需采取措施防范或规避风险。研究成果对于边坡治理工程决策及风险管理具有指导意义。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 0.0619 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.

关 键 词：地震危险性 倾倒变形边坡 失稳概率 易损性 定量风险分析 

分 类 号：P642.22[天文地球—工程地质学]