降雨条件下土坡饱和-非饱和渗流及稳定性分析

基于非饱和土力学理论，利用有限元法对降雨条件下边坡的饱和-非饱和渗流及稳定性进行了探讨。数值分析表明，雨水入渗使边坡非饱和区土体的基质吸力减小，是导致边坡稳定性降低的主要因素。进而考察了基质吸力的不同取值及裂隙的不同位置对边坡稳定性的影响，结果表明：在降雨初期基质吸力取值越大，得到的边坡安全系数越高，但经过长时间降雨即边坡土体基本达到饱和后，基质吸力的取值不同对边坡安全系数基本上没有影响；裂隙的存在为雨水入渗提供了良好的通道，因而导致边坡稳定性相对于无裂隙状态来说有所降低。降雨初期下游裂隙使边坡稳定性降低较快，但随着降雨历时的增加，即下游土体逐渐变为饱和状态后，边坡的稳定性变化则主要由上游裂隙控制。

Seepage and stability analysis of saturated-unsaturated soil slope under rainfall infiltration

Based on the theory of unsaturated soil, seepage and stability of slope under rainfall infiltration are studied with finite element method. It is shown that the matric suction reduced by rainfall infiltration is the key factor which causes the slope stability decreased. Furthermore, the influence of different values of matric suction and different locations of cracks on slope stability is analyzed. Results show that the greater values of matric suction, the greater factor of safety (FOS) of slope at primary state of rainfall, while this effect will decreased with rainfall went on. It is convenient for rainfall infiltration with cracks, so the FOS decreased by cracks in general. The FOS controlled by downstream cracks of slope at primary state of rainfall, while the upstream cracks will become more important to FOS with continuous rainfall.