降雨作用下碎石土滑坡稳定性演化过程分析

Stability Evolution of Debris Landslides under Rainfall

摘要:

不同的降雨强度和历时导致滑坡体内渗流场的动态演变，同时也影响着滑坡稳定性的变化，但目前对降雨作用下的滑坡稳定性变化规律的研究并不多。本文选取铜仁地区石灰溪滑坡进行案例研究，基于饱和—非饱和渗流理论和极限平衡理论，采用SLOPE/W模块研究在不同降雨强度及不同降雨历时组合工况作用下石灰溪滑坡在降雨中及降雨后1~7天的稳定性演化特征及规律。研究表明在不同降雨强度条件下，滑坡稳定性在第一天降雨过后急剧恶化，稳定性系数迅速减小，随着降雨强度的增大滑坡稳定性恶化明显，当降雨强度为100 mm/d时滑坡稳定性已经基本接近于整体滑动的状态；滑坡在降雨过程中稳定性系数迅速减小，随着降雨历时的增大滑坡稳定性恶化明显，当降雨历时为2天、3天时滑坡已经整体失稳。

Abstract:

Rainfall is one external，dynamic factor that may induce landslide formation.Different rainfall intensities and rainfall durations affect the dynamic development of the seepage field，which may lead to a change in landslide stability.Research is limited regarding rainfall effects on landslide stability；therefore，a reliable basis for the deformation failure mechanism and mode analysis under heavy rainfall cannot be provided.This article examines a case study of the Shihuixi landslide in the Tongren region by applying a combination of different rainfall intensities and rainfall durations.Shihuixi landslide stability is evaluated using saturated unsaturated seepage theory and limit equilibrium theory and the SLOPE/W module.The research shows that under different rainfall intensity conditions，landslide stability deteriorated sharply after the first day of rain.Increases in rainfall intensity cause the stability coefficient to decrease rapidly，hence，significantly reducing landslide stability.When the rainfall intensity was 100 mm/d，landslide stability was basically close to whole sliding state.When rainfall duration increases，the landslide stability deteriorates sharply and the stability coefficient rapidly decreases.Landslide stability deteriorated significantly，when the rainfall duration was 2 days or 3 days.