降雨诱发震后松散堆积滑坡的启动试验研究  

An experimental study of the failure mechanism of shallow landslides after earthquake triggered by rainfall

作　　者：汤明高[1] 许强[1] 李九乾 罗剑[1] 匡野[1] 

机构地区：[1]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),四川成都610059 [2]四川省交通运输厅交通勘察设计研究院,四川成都610017

出　　处：《水文地质工程地质》2016年第4期128-134,140,共8页Hydrogeology & Engineering Geology

基　　金：国家重点基础研究发展计划(2013CB733202);国家重点实验室自主课题(SKLGP2015Z008);国电猴子岩水电科研专题(CGC-HZY201310)

摘　　要：通过不同降雨入渗形式和潜在滑动面倾角的滑坡模型试验,分析了强震后松散堆积体的降雨入渗过程及变形启动机理,研究认为:当降雨渗流至前缘孔隙水压力突增时滑坡启动,松散堆积体抗滑段土体的有效应力快速下降甚至局部液化是导致滑坡失稳的主要原因。滑坡启动时的临界孔隙水压力及临界位移量与主滑段滑面倾角呈负相关关系。滑坡中后部的变形具有渐变特征而前部的变形则具有明显的突发特征。最后在试验基础上分析建立了强震后松散堆积滑坡临界启动的地质-水文-力学机制模型,提出了识别预警指标。A massive loose detritus and soil accumulate along the trench after the earthquake,and rainfalls easily induce landslide and debris flow. In this paper,by means of the model experiments of different rainfall infiltration and sliding surface dip angle of the landslide,the deformation process,failure mechanism and the characteristics of groundwater and pore water pressure were analyzed. The research results show that infiltration of groundwater is the key factor to induce the deformation of shallow soil landslide. The fast decrease of the effective stress and the partial liquefaction of soil in the anti sliding section of landslide are the main trigger cause for the initiation of the shallow soil landslide. The deformation time,the instability initiation time and the critical pore water pressure of the landslide are obviously negatively and nonlinearly related to the dip angle of the sliding surface. The deformation characteristics of different parts of the landslide are different,and the deformation of the middle part has three stages,and the deformation of the front part has a mutation.When the pore water pressure increases to a certain threshold with the seepage development,the deformation of the landslide is accelerated. When the pore water pressure suddenly starts to decrease,the landslide occurs. On the basis of the experiment, the geology-hydrology-mechanics model of the shallow loose accumulative landslide is established. Combining the geological conditions,the recommended index of the early warning is put forward. The research results have important significance for guiding the monitoring and early warning of shallow soil landslides and the initiation identification of loose accumulation of debris flow after earthquake.

关 键 词：强震 松散堆积滑坡 降雨 孔隙水压力 识别与预警 

分 类 号：P642.22[天文地球—工程地质学]