降雨条件下某堆积体饱和-非饱和渗流及稳定性分析

Analysis on the Saturated-unsaturated Seepage and Stability of an Accumulation Slope under Rainfall Infiltration

降雨是诱发滑坡的主要因素之一。本文以西南地区某堆积体为例,基于非饱和土力学理论,考虑降雨入渗的影响,利用有限元方法,对持续强降雨条件下该堆积体的饱和-非饱和渗流场动态变化、变形破坏机理及稳定性进行了数值模拟和计算,结果表明:降雨入渗使坡体非饱和区土体的基质吸力减小,是导致堆积体稳定性降低的主要因素;随着降雨的持续,堆积体塑性区的范围及贯通距离增加,稳定系数逐渐降低,使整体失稳滑移的危险增大。

Rainfall is one of the main triggering factors for landslide. Based on the theory of unsaturated soil mechanics,the impact of rainfall in filtration on an accumulation slope is studied in detail as a typical example in Southwest China. The dynamic changes of the seepage field of the accumulation slope and its deformation mechanism and stability under continual intense rainfall are computed using the finite element method. The results show that the reduction of matric suction is one of the main factors causing a considerable reduction in the stability of the accumulation slope under rainfall infiltration. Furthermore, the plastic zone of the accumulation slope will further extend as the rain continues. As the stability gradually decreases, the risk of slope failure will increase.