降雨入渗和再分布对边坡土壤水分运移的数值模拟研究

Study on Simulation of Soil Water Transportation in Slope under Rainfall Infiltration and Soil Water Redistribution

根据饱和-非饱和土壤水分运移的混合型Darcy-Richards方程,建立了降雨入渗和再分布条件下非饱和边坡土壤水分运移模型,并采用有限差分方法对模型进行数值求解,选取广州西二环高速公路C10标的路堑边坡进行降雨入渗和再分布下坡面土壤水分分布的动态规律研究。模拟结果表明:随着降雨历时的增加,湿润锋面逐渐向下推进,当入渗时间达到8小时后,土壤中体积含水量达到饱和含水量。降雨5小时后停止降雨,分析边坡表层土壤再分布下含水量的递减随时间的变化关系为y=0.25262+0.1742exp(-t/8.70805)。数值模拟及分析结果可为边坡排水加固设计提供定量依据,并对边坡稳定性评价具有理论意义和现实意义。

Based on Darcy-Richards equation of mixed type in the saturated and unsaturated soil water transportation, the soil water transportation model of rainfall infiltration and soil water redistribution in the slope was established. Solutions to the mathematical model were accomplished by the finite difference method, The cutting slope in the C10 bid section of Guangzhou Xierhuan Highway was selected for dynamic studying on transport law of soil water redistribution. The simulative results show that wetting front gradually moved to deep soil in the slope with rainfall lasting-time increasing, and volumetric water contents reached to saturation water contents under 8 hour’s rainfall infiltration. According to the analysis surface layer soil after 5 hour’s rainfall, the variation relationship between decreasing of redistribution volumetric water contents and the time is y=0.25262＋0.1742exp（-t / 8.70805）.The result of numerical simulation and analysis can provide quantitative basis for draining reinforcement design, and has important theoretical and practical significance for slope stability evaluation.