融合观测信息的降雨诱发斜坡失稳机理及可靠度分析  

Rainfall-induced slope failure mechanism and reliability analyses based on observation information

作　　者：蒋水华[1,2] 刘贤 黄发明 黄劲松[1] 张婉彤 JIANG Shui-hua;LIU Xian;HUANG Fa-ming;HUANG Jin-song;ZHANG Wan-tong(School of Civil Engineering and Architecture,Nanchang University,Nanchang 330031,China;State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China)

机构地区：[1]南昌大学建筑工程学院,江西南昌330031 [2]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072

出　　处：《岩土工程学报》2022年第8期1367-1375,I0003,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52179103,41867036,41972280);江西省自然科学基金项目(20212BAB204054);水资源与水电工程科学国家重点实验室开放研究基金项目(2019SGG03);江西省研究生创新基金项目(YC2020-S123)。

摘　　要：目前降雨诱发滑坡机理及可靠度研究不仅很少同时考虑土体水力参数和抗剪强度参数空间变异性的影响,而且忽略了“天然工况下斜坡基本上不会发生失稳破坏”这一客观事实。以无限长斜坡模型为例,融合观测信息提前对空间变异抗剪强度参数进行概率反演分析,再建立非平稳随机场模型模拟土体渗透系数的空间变异性及非平稳分布特征,在蒙特卡洛模拟框架下评估不同降雨历时下斜坡失效概率及最危险滑动面分布特征。在此基础上,探讨同时考虑土体水力参数和抗剪强度参数空间变异性的降雨诱发斜坡失稳机理。结果表明:利用概率反演获得的抗剪强度参数后验信息,计算的斜坡失效概率由先验的28.1%降至7.2%。不同降雨阶段斜坡失稳的诱因不同,如果忽略“天然工况下斜坡不会失稳破坏”这一观测信息,将会造成对降雨诱发斜坡失稳机理和失效概率的错误估计,特别是在降雨初期。The rainfall-induced slope failure mechanism and reliability analyses rarely consider the spatial variability of hydraulic and shear strength parameters at the same time and ignore a fact that the slopes always keep stable under the natural condition. An infinite slope model is taken as an example to conduct probabilistic back analyses of spatially varying shear strength parameters using the observation information in advance. Then, a non-stationary random field model is established to simulate the spatial variability and non-stationary distribution feature of the hydraulic conductivity. The probabilities of slope failure and distributions of the critical slip surface under different rainfall durations are evaluated within the framework of Monte-Carlo simulation. Based on these, the rainfall-induced slope failure mechanisms considering the spatial variability of hydraulic and shear strength parameters simultaneously are investigated. The results indicate that the probability of slope failure evaluated based on the posterior information of shear strength parameters obtained from the probabilistic back analyses is reduced from 28.1%(prior) to 7.2%. It is found that the triggering factors for the slope instability are different for different rainfall stages. The rainfall-induced slope failure mechanism and probability of failure will be erroneously evaluated, especially at the initial stage of rainfall, if the field observation information is ignored.

关 键 词：斜坡 降雨入渗 失稳机理 空间变异性 概率反演 可靠度分析 

分 类 号：TU47[建筑科学—结构工程]