降雨条件下岩体边坡稳定性数值模拟与分析

A Numerical Simulation and Analysis of Stability of Rock Slope under Rainfall Condition

根据某高速公路岩体边坡的实际情况和基本资料,选定典型边坡,建立降雨入渗条件下该边坡非稳定饱和-非饱和渗流分析的有限元模型,分析在汛期暴雨和平均降雨两种工况下边坡内的地下水渗流场及其变化规律,确定地下水荷载。进一步模拟边坡分级开挖、支护过程,计算分析各阶段边坡应力变形规律和位移变化,以及在2种工况下的边坡稳定性。结果表明,降雨后的最小安全系数比降雨前有所减小,局部安全系数小于1.0,有滑坡危险;锚索支护后降雨的最小安全系数比支护前要大,较小安全系数的分布范围有一定的减小,安全系数提高幅度较大,能满足稳定性要求。该结果不仅可以为工程施工提供科学的理论依据,而且对边坡加固措施以及滑坡的预测预报也具有重要的指导作用。

According to the actual engineering conditions of an expressways slope, the finite dement model of the rock slope is set up under the rainfall conditions by unstable saturated-unsaturated seepage flow with rainfall infiltration. The law of the groundwater seepage field of the slope under two conditions of heavy rain in the flood seasons and continuous rainfall conditions are calculated and analyzed, and the underground water load is determined. The process of stage excavation and reinforcement of the slope are further simulated, and the stress and deformation law and displacement change of the slope during each stage are analyzed, and the stability of slope is evaluated under two conditions. The results that the minimum safety factor after rainfall is smaller than before rainfall, and the local safety factor is less than 1.0, so there is a risk of landslide. The minimum safety factor after rainfall with support of mooring wire rope is bigger than without support, and the distribution of smaller safety factors certainly decreases, so the safety factor is raised greatly, which can meet the stability demands. The results not only provide a scientific basis for the project construction, but also play an important guiding role in the slope reinforcement measures and landslide forecast.