大型堆积体滑坡持续降雨条件下破坏机制研究

Failure mechanism of large accumulation landslide under continuous rainfall condition

堆积体滑坡是一种典型的、多发的滑坡类型,大多数土质滑坡均属此类,其中80%以上的土质滑坡都是由持续性降雨或者暴雨引发。介于上述原因,采用Geo-studio软件中的SEEP/W模块和SIGMA/W模块,以贵州省沿河县院子岩滑坡为例,对持续降雨条件下,滑坡体内二维渗流场及应力场进行数值模拟耦合分析,分析在持续降雨条件下大型堆积体滑坡变形破坏机制。模拟结果显示,持续降雨条件下雨水渗入滑坡中后沿岩土接触面流动,对滑带土进行浸润、软化、冲刷;滑坡体内的孔隙水压力以及动水压力不断增大,在坡脚处有效应力减小,在此过程中坡体应力不断调整,局部出现应力集中和位移增大,进而造成坡体失稳破坏。

Accumulation landslide is a typical and frequently occurring landslide type,and most soil landslides belong to this type.More than 80%of landslides are caused by persistent rainfall or heavy rain.For these reasons,we used the SEEP/W module and the SIGMA/W module of Geo-studio software to simulate the two-dimensional seepage field and stress field of Yuanziyan Landslide in Yanhe County,Guizhou Province,and analyzed the deformation and failure mechanism of large-scale accumulation landslide under continuous rainfall.The simulation results show that,under the condition of continuous rainfall,rainwater infiltrates into the landslide and flows along the rock-soil contact surface,wetting,softening and scouring the sliding zone soil;the pore water pressure and hydrodynamic pressure in the landslide body increase continuously,and the effective stress at the foot of the slope decreases.In the process,the stress of the slope body adjusts continuously,and the stress concentration and displacement increase locally,resulting in the instability and failure of the slope body.