开挖和降雨耦合诱发滑坡机理分析——以四川万源前进广场滑坡为例  

Analysis of landslide mechanism induced by excavation and rainfall:A case study of the Qianjin square landslide in Wanyuan City,Sichuan Province

作　　者：蒋涛 崔圣华 冉耀 JIANG Tao;CUI Shenghua;RAN Yao(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Sichuan Institute of Geological Engineering Exploration Group Co.Ltd.,Chengdu,Sichuan 610059,China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059 [2]四川省地质工程勘察院集团有限公司,四川成都610059

出　　处：《中国地质灾害与防治学报》2023年第3期20-30,共11页The Chinese Journal of Geological Hazard and Control

基　　金：国家自然科学基金项目(41907254)。

摘　　要：近年来人类工程活动和降雨环境耦合诱发的地质灾害事件频发,而耦合作用机制还待深入研究。文中以开挖和降雨耦合诱发的四川万源前进广场滑坡为例,结合前进广场滑坡地表位移及深部位移监测数据和降雨数据分析滑坡变形破坏特征和形成机理。研究表明:(1)前缘基坑的开挖是导致老滑坡复活最主要的原因,降雨起到了激发和加速作用;(2)前缘基坑开挖一方面为滑坡提供了良好的临空面条件,另一方面导致后方土体失去支撑,导致滑坡由前至后产生多级台坎状拉裂下错变形;(3)基坑开挖后,研究区长时间强-中降雨,地表水通过开挖导致的张拉裂缝进入坡体内部,一方面基岩裂隙水受大气降雨补给,导致部分非饱和土变为饱和土、承压水压力增大、有效应力下降,另一方面,部分地下水可能到达滑带,驱动变形发展。最终文中提出了由于斜坡前缘基坑开挖与降雨耦合导致滑坡的“基坑开挖-斜坡多级拉裂-集中降雨-滑带弱化-加速变形”演化过程机制。In recent years,there has been a frequent occurrence of geological disasters caused by the coupling of human engineering activities and rainfall environment.However,research on the mechanism of coupling has not been deeply explored.In this paper,the landslide of Qianjin square in Wanyuan City induced by the coupling of excavation and rainfall is taken as an example,and the characteristics and formation mechanism of landslide deformation and failure are analyzed by combining the monitoring data of surface displacement and deep displacement of the landslide of Qianjin square and the rainfall data.The study shows that:(1)excavation is the main reason for the reactivation of the old landslide,while rainfall plays a triggering and accelerating role;(2)excavation provides good airspace conditions for the landslide on the one hand,and on the other hand causes the soil behind it to lose support,leading to the misalignment of the landslide from front to back;(3)after excavation,long-term strong to moderate rainfall in the study area,combined with tension cracks caused by excavation,make it easier for surface water to enter the interior of the slope.The bedrock fracture water is replenished by atmospheric rainfall,resulting in some unsaturated soil becoming saturated soil,increasing the pressure of pressurized water and decreasing effective stress.Additionally,groundwater may reach the slip zone and drive the deformation development.Finally,the process mechanism of landslide induced by excavation and rainfall coupling is proposed as“excavation-slope multi-stage cracking-concentrated rainfall-slip zone weakening-accelerated deformation”.

关 键 词：人工开挖 降雨 大型滑坡 变形破坏特征 形成机理 

分 类 号：P642.2[天文地球—工程地质学]