融合历史降雨下斜坡稳定性观测信息的可靠度分析  

Slope Reliability Analysis Incorporating Observation of Stability Performance under A Past Rainfall Event

作　　者：刘贤 揭鸿鹄[2] 蒋水华 黎学优 黄劲松 Liu Xian;Jie Honghu;Jiang Shuihua;Li Xueyou;Huang Jinsong(School of Civil Engineering,Sun Yat‐Sen University,Zhuhai 519082,China;School of Infrastructure Engineering,Nanchang University,Nanchang 330031,China)

机构地区：[1]中山大学土木工程学院,广东珠海519082 [2]南昌大学工程建设学院,江西南昌330031

出　　处：《地球科学》2023年第5期1865-1874,共10页Earth Science

基　　金：国家重点研发计划项目(No.2021YFC3001000);国家自然科学基金资助项目(Nos.52179103,52222905,41972280,42272326);江西省自然科学基金项目(No.20224ACB204019);江西省水利科学院开放研究基金项目(No.2021SKSG02).

摘　　要：降雨诱发斜坡失稳机理及可靠度分析通常忽略了现场观测信息的影响,包括斜坡在天然条件下保持稳定或经历历史降雨后保持稳定等观测信息.以无限长斜坡模型为例,采用贝叶斯更新方法基于“斜坡经历某次历史降雨后仍保持稳定”这一现场观测信息概率反分析空间变异水力和抗剪强度参数,基于蒙特卡洛模拟方法计算不同降雨历时下斜坡失效概率,对比分析忽略观测信息对斜坡失效概率估计所造成的影响.结果表明:概率反分析通过融合历史降雨下斜坡稳定性观测信息,可有效排除因抗剪强度参数空间变异性导致斜坡沿软弱层发生失稳的可能性,为客观评价降雨诱发的空间变异斜坡失效概率奠定了基础.如果忽略“斜坡经历某次历史降雨后仍保持稳定”这一观测信息会明显高估斜坡失效概率,尤其在降雨初期.本研究成果为揭示降雨诱发斜坡失稳机制提供新的视角.Failure mechanism and reliability analysis of rainfall-induced slopes generally ignore the effects of field observation information,such as the observation that the slope keeps stable in natural conditions or after a historical rainfall event.In this paper,with an infinite slope model as an example,the BUS(Bayesian Updating with Subset simulation)method is adopted for the probabilistic back analysis of spatially variable hydraulic and shear strength parameters based on the field observation that the slope survived from a previous extreme rainfall event.The probabilities of slope failure under different rainfall durations are evaluated within the framework of Monte-Carlo simulation.The influence of ignoring/incorporating the field observation on the estimate of probability of slope failure is also investigated.The results indicate that the possibility of slope failing along the weak zones caused by the spatial variability of soil parameters can be effectively excluded through the probabilistic back analysis incorporating the field observation.Based on this,more realistic probability of slope failure induced by the rainfall can be produced.If the field observation that the slope survived from a previous extreme rainfall event is ignored,the probability of slope failure will be significantly overestimated,especially in the early stage of rainfall.The research outcomes provide a new perspective for interpreting the rainfall-induced slope failure mechanisms in the spatially variable soils.

关 键 词：斜坡 滑坡 降雨入渗 空间变异性 概率反分析 可靠度分析 灾害地质. 

分 类 号：P694[天文地球—地质学]