降雨入渗非饱和花岗岩残积土边坡稳定性分析

Stability Analysis on Unsaturated Granite Residual Soil Slope Under the Rainfall Action

针对福建地区典型边坡,基于非饱和渗流理论以及非饱和土力学理论,分析降雨入渗条件下边坡形态(高度、坡率)、物理力学参数(密度、有效黏聚力、有效内摩擦角)等对边坡渗流场与稳定性的影响机理。结果表明:降雨对矮边坡稳定性的影响明显更强。降雨过程中,天然含水量越大,边坡安全系数下降越快。边坡稳定性随土体有效粘聚力和有效内摩擦角的增大而增大,变化率分别为0.0426/k Pa、0.0319/°。粗粒土边坡滑裂面基本为直线,易形成边坡浅部失稳。增大有效粘聚力降低有效内摩擦角,边坡滑裂面逐渐向边坡深部发展,同时滑裂面的形状逐渐由直线转变为曲线型。

This paper indicates that the influence mechanism of some factors including slope shape(e.g.height,slope),physical and mechanical parameters(e.g.density,effective cohesion and effective internal friction angle)on slope seepage field and stability for typical slope in Fujian Province based on the unsaturated seepage theory and unsaturated soil theory.The results show that rainfall has greater influence on low slope.The slope with high water content is easy to be instable during the rainfall process.The safety factor of slope increases with the increase of the effective cohesion and effective internal friction angle of the soil,and the change rates are0.0426/kPa and0.0319/°,respectively.The slippery surface of the coarse-grained soil slope is straight and shallow slope will tend to be instable.With the increase of the effective cohesion or the decrease of the effective internal friction angle,the slope slip surface will locate in the deep of slope and the shape of the sliding surface will tend to curve gradually.