降雨过程中边坡临界滑动场

Critical slip field of slope in process of rainfall infiltration

降雨入渗过程中孔隙水压力的升高与基质吸力的降低引起边坡稳定性的下降,是导致边坡滑塌的主要诱导因素。利用饱和-非饱和渗流有限元计算得到的孔隙水压力场,基于Fredlund提出的非饱和土抗剪强度理论,对边坡临界滑动场进行改进,提出可以考虑降雨过程的边坡临界滑动场数值模拟方法,能够方便、快速地计算出边坡局部、整体安全系数和相对应的临界滑动面在降雨过程中的变化历程。将该法用于一个典型均质边坡和一个非均质边坡在降雨过程中的稳定性计算,分析降雨持续时间、降雨强度和非饱和强度参数取值等因素对边坡稳定性的影响,并将计算结果与其他方法进行比较,结果表明临界滑动场方法能搜索任意形状最危险滑面,计算的安全系数合理。

The rising of pore water pressure and decreasing of matric suction in the process of rainfall infiltration into slope is the main factor of slope failures.Numerical simulation method of critical slip field of slope considering rainfall process is proposed based on proposed unsaturated soil shear strength theory and water pressure field obtained by finite element analysis of saturated-unsaturated seepage.Thus,slope local safety factor and slope whole safety factor as well as the corresponding critical slip surfaces during infiltration are calculated conveniently and rapidly.This method has been applied to the stability analysis of two example slopes and the effect study of rainfall intensity,duration and strength parameter on slope stability.The results show that the critical slip field method could search for any shape of the most dangerous slip surface;and the safety factor is reasonable.