降雨诱发浅层滑坡渐进破坏分析研究

Research on the progressive failure of rainfall-induced shallow landslide

为分析降雨诱发浅层滑坡的演变过程。本文以湖南湘西古丈滑坡为例,基于Green-Ampt入渗模型,进行了降雨诱发浅层滑坡渐进破坏分析。研究结果表明:在强降雨作用下,滑坡的失稳破坏主要是由于前缘土体以及中前部土体的局部破坏,而逐渐发展为整体破坏。并且,受滑坡地形影响,地形平缓的区域虽然湿润锋下渗较快,土体抗剪强度较低,但由于土体饱和带的渗流作用较小,而重力提供垂直于滑面的分力较大,该部分稳定性较为良好,故湿润锋对于滑坡稳定性的影响还应该根据不同地形条件加以分析。渐进式滑坡破坏分析方法对滑坡的监测和防治具有重要的指导意义。

In this paper,based on the Green-Ampt infiltration model,considering the seepage effect of the saturated zone above the wet front and the influence of the wet front on the shear strength of the soil,combined with the landslide progressive failure analysis method,a rainfall-induced shallow landslide progressive failure analysis method is proposed.Taking Guzhang landslide in Xiangxi,Hunan Province as an example,the deformation and failure development of the landslide under heavy rainfall is analyzed.The results show that the instability and damage of the Guzhang landslide is mainly due to the partial damage of the front soil and the middle and front soil,which gradually develops into an overall damage under the heavy rain.Affected by the landslide terrain,terrain flat areas while wetting front infiltration faster,the shear strength of soil is low,but due to the effect of seepage of the soil saturated with smaller,gravity to provide component perpendicular to the sliding surface is larger,the partial stability is relatively good,so the influence of wetting front for landslide stability should also be analyzed according to different terrain conditions.The method of progressive landslide damage analysis has important guiding significance for landslide monitoring and prevention.