降雨入渗条件下软岩边坡稳定性分析

降雨条件下软岩边坡的失稳模式是进行边坡处治的基本依据之一。为研究软岩边坡在降雨条件下的稳定性，提出了一种既能考虑渗流场对边坡稳定性的影响，又能体现岩石软化效应对边坡失稳所带来的不利作用的新方法。运用二维渗流数值计算方法，对降雨条件下的边坡孔隙水压力大小及暂态饱和区面积在空间及时间上的分布进行了模拟。并将渗流场计算结果与暂态饱和区岩石软化试验所得岩石物理力学参数随时间的取值相结合，采用强度折减法分析软岩边坡在降雨入渗条件下的稳定性。对算例边坡的研究表明：降雨入渗条件下软岩边坡的失稳在降雨初期表现为边坡表层局部分层垮塌。随着降雨历时的增长，失稳形式则表现为局部分层垮塌与整体滑移相结合。降雨停止后，边坡负孔隙水压力的消散，对软岩边坡安全系数的继续降低具有一定的延缓作用。

Stability analysis of soft rock slope under rainfall infiltration

Instability mode of soft rock slope in rainy condition is one of bases for slope disposal.In order to research the stability of soft rock slope under rainfall infiltration,this article put forward a new method which not only can consider the impact of seepage field on the slope stability but also can reflect the adverse effect on the slope instability caused by rock softening effect.Two-dimensional seepage numerical calculation method is used to simulate the slope pore water pressure size and the distribution of transient saturated zone area on space and time in rainy condition.Combined the seepage field calculation results with the value of physico-mechanical parameters of rock which are obtained from transient saturated zone area soften rocks test versus time,and strength reduction method is used to analysis the stability of soft rock slope under rainy infiltration condition.The research of example slope indicates that: in early rainfall period the representation of soft rock slope instability is the local layered collapsing of slope surface under rainy infiltration condition.With the growth of rainfall duration,the representation form of the instability is the combined local layered collapsing with whole sliding.After rainfall stopping,the recovery of slope negative pore water pressure has certain delayed effect for the continuous reduction of safety coefficient of soft rock slope.