基于强降雨的膨胀土边坡稳定性分析

采用Midas-GTS软件，基于非饱和土强度理论Fredlund强度公式和饱和土有效应力原理，分析安康地区某膨胀土边坡在强降雨工况下坡体内各土层的孔隙水压力变化，并利用渗流-应力耦合研究边坡的稳定性。研究结果表明：随着降雨持时增加，膨胀土边坡体内孔隙水压力逐渐增大，表层膨胀土逐渐饱和，膨胀土的抗剪强度逐渐降低；同时降雨引起边坡体内地下水水位变化产生变化的空隙水压力。通过渗流-应力耦合分析，得出暴雨工况下不同降雨持时的边坡安全系数，其随降雨持时增加而逐渐减小，在降雨持时24h时安全系数降至0．89。

Analysis for Stability of Expansive Soil Slopes Based on Heavy Rainfall

This paper analyzes water pressure changes in voids on all soil layers of some expansive soil slope soil s in Ankang region under heavy rainfall by means of Midas-GTS software and based on unsaturated trength theory Fredlund strength formula and effective stress principle of saturated soil, and studies stability of slope by means of seepage-stress coupling. The results of research show that with increase of rainfall duration, water pressure in voids of expansive soil slopes increases gradually, surface expansive soil satnrates gradually, and the shear strength of expansive soil decreases gradually; and meanwhile changes of underground water level inside the slopes caused by rainfall produce variable water pressures in voids. Through seepage-stress coupling analysis, the paper obtains slope safety factor in different durations under the condition of rainstorm, which decrease gradually with increase of rainfall duration and down to 0. 89 when rainfall lasts for 24h.