降雨和蒸发对粉质黏土边坡稳定性影响分析

以山西某露天矿粉质黏土边坡为工程背景,基于饱和-非饱和渗流理论及流固耦合原理,采用有限单元法研究了降雨和蒸发作用下边坡孔隙水压力、体积含水量、位移及应变变化特点,并对不同降雨强度和蒸发强度下的边坡孔隙水压力和安全系数进行了对比分析。研究结果表明:降雨入渗导致浅层土体含水量增大,基质吸力降低,降低边坡稳定性,降雨强度越大,边坡稳定性下降越快;蒸发会降低浅层土体的含水量,增加吸力,提高边坡稳定性,且蒸发强度越大,安全系数提高越快;边坡孔隙水压力和安全系数与天气条件之间存在滞后关系,滞后时间随土体深度增加而增加。

Effect analysis of rainfall and evaporation on silty clay slope stability

Based on saturated-unsaturated seepage theory and fluid-solid coupling mechanism, the features of pore-water pressure, volumetric water content, displacement and strain in a silty clay slope of an iron open-pit mine in Shanxi are analyzed using the finite difference method under the condition of rainfall and evaporation. At the same time, pore-water pressure and safety factor are comparatively analyzed under different intensity of rainfall and evapora- tion. The research results show that the rainfall infiltration leads to increasing water content in shallow soil, reduces suction and decreases slope stability, and that the more rainfall intensity increases, the more the slope stability decreases; evaporation will reduce the shallow soil water content, increase suction and decrease slope stability. Additionally, the greater the evaporation intensity is, the faster the safety factor increases; the changes in slope stability and pore-water pressure lag behind the changes of weather, and the lag time will increase with soil depth.