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为了研究排土场层状碎石土边坡在短时强降雨条件下的入渗过程及稳定性,首先在SEEP/W中进行降雨条件下的饱和-非饱和渗流分析,得到不同时刻的瞬态孔隙水压力分布,然后将SEEP/W模拟结果分别导入SIGMA/W和SLOPE/W,进行孔压-应力耦合分析和边坡稳定分析。最后通过对雨后不同时刻边坡内部孔隙水压力值变化情况的比较分析,探讨了雨后滑坡的发生机理。研究结果表明:强降雨对排土场碎石土边坡浅层影响最大,边坡浅层基质吸力随含水量的增大迅速降低,降低范围逐步向深部扩展,雨后基质吸力缓慢增大;降雨时排土场边坡渗流流速较大的区域主要集中在透水性最强的边坡浅层,当坡底存在弱透水层时,坡脚会很快产生涌水现象,涌水速度会逐渐增大,地下水位也会随之提高,雨后涌水减弱,地下水位降低;排土场边坡位移在降雨初期增加最快,之后增加速度趋缓,雨后会继续增大;降雨时排土场边坡安全系数快速下降,雨后随着边坡浅层水分继续下渗,边坡浅层下部含水量升高,最危险滑面位置会向基质吸力减小的边坡浅层下部发生转移,因此安全系数会继续降低至最小值,然后才开始缓慢增大。排土场层状碎石土边坡在短时强降雨作用下容易在雨后的一个较短时间内发生浅层滑坡。
In order to study the infiltration process and stability of the layered gravel soil slope under the condition of short-term heavy rainfall, the saturation-unsaturated seepage analysis under the condition of rainfall in SEEP / W was firstly carried out to obtain the instantaneous State pore water pressure distribution, and then the SEEP / W simulation results were imported into SIGMA / W and SLOPE / W respectively for pore pressure-stress coupling analysis and slope stability analysis. Finally, by comparing and analyzing the changes of pore water pressure at different times after rain, the mechanism of landslide after rain is discussed. The results show that heavy rainfall has the strongest influence on shallow soil of gravelly soil in the dump site, and the suction of shallow slope decreases rapidly with the increase of water content. The range of depression gradually expands to the deep and the suction of substrate increases slowly after rain. When the rainfall is high, the seepage flow velocity in the dump slope is mainly concentrated in the shallow water layer with the highest water permeability. When the bottom of the slope has a weak aquitard, the slope foot will quickly produce gushing water and the water gushing speed will gradually increase , The groundwater level will also increase. After the rain, the gushing water will be weakened and the groundwater level will be lower. The displacement of the dump slope will increase fastest in the early stage of rainfall, then increase slowly, and will continue to increase after rain. As the slope shallow water continues to seep through the rain, the water content in the lower part of the slope increases and the position of the most dangerous slip surface shifts to the lower part of the shallow slope where the matrix suction decreases. Therefore, The safety factor will continue to decrease to a minimum before it begins to increase slowly. Dump soil layered gravelly soil slope in the short-term strong rainfall prone to shallow rainfall in a short period of time after the landslide.