持续降雨条件下土质边坡渗流特征分析

Analysis for Seepage Features of Soil Slopes Under Continuous Rainfall

选取斜坡体的简化剖面,考虑降雨入渗因素,基于多孔介质饱和-非饱和渗流理论,模拟不同时间段边坡不同土层的渗流变化,并探讨各土层孔隙水压力随时间和空间的变化规律。数值模拟表明,随着降雨时间增加,边坡各土层孔隙水压力均呈上升趋势,随着水平距离和垂直距离增加,孔隙水压力曲线呈下降趋势;降雨入渗使土体渗流条件发生改变,水分向坡角范围渗透并积聚,导致坡脚处孔隙水压力骤增;降雨条件下含水量较之无降雨条件时有较大上升,随着时间增加各土层逐渐达到其储水能力而使含水量不再变化。因此,对于降雨条件下的土质边坡,坡脚尤其需要加强排水和防护。

By selecting simplified profile of slope bodies, considering infiltration factors of rainfall and based on saturated and unsaturated porous media seepage theory, this paper simulates seepage changes of different soil layers on slopes in different periods of time and investigates change law of pore water pressures on various soil layers with time and space. The numeric simulation indicates that pore water pressures on various soil layers of slopes show a rising trend with increase of rainfall duration, while the pore water pressure curves show a downtrend with increase of horizontal and vertical distances. Rainfall infiltration enables change of seepage conditions of soil, and moisture permeates towards the scope of slope angle and accumulates, leading to abrupt increase of pore water pressure at slope angle; the water content during rainfall is rather larger than the content without rainfall, and all soil layers gradually reach their storage capacity with time to enable no change of water content any more. Therefore, for soil slopes on the condition of rainfall, drainage and protection of slope angle should be especially strengthened.