降雨对非饱和土质边坡含水率的影响分析

Influence of Rainfall on the Moisture Content of Unsaturated Soil Slopes

降雨对边坡的稳定性具有重要影响。在降雨作用下,土体含水率增加,抗剪强度降低。基于土水特征曲线压力板仪试验系统并结合Geo Studio中的SEEP/W提供的典型土-水特征曲线建立非饱和渗流模型,分析了不同降雨历时下,土体渗透系数对非饱和土质边坡含水率分布的影响。结果表明:当土体渗透性较差时,入渗深度较浅,且在短期内入渗深度即保持稳定;但当土体渗透性较好时,入渗深度和达到入渗深度稳定的降雨历时都随之增加。坡脚部位由于受坡体上部结构坡表径流及下渗水补给,土体含水率最大,应保证该部位排水设施的通畅,防止坡脚部位下渗水导致土体含水率过大,影响边坡稳定性。

Rainfall has an important effect on the stability of soil slopes. Under rainfall infiltration,the water content of soil slope increases,while the shear strength decreases. Based on the soil-water characteristic curve pressure plate test system and the typical soil water characteristic curve provided by SEEP / W,the unsaturated seepage model was established and the moisture content of unsaturated soil slope in different permeability coefficient under rainfall was studied. The results indicate that when the permeability of the soil mass is poor,the infiltration depth is shallow,and the rainfall duration which is required for maintaining steady infiltration depth is short. But when the permeability is good,the infiltration depth and rainfall duration are both increased. Due to the runoff in the superstructure of the slope and the supply of infiltration water,the moisture content in the toes of the slope is maximal.So unobstructed drainage facilities in this section should be ensured to prevent excessive moisture content of the slope toes caused by infiltration,so as to maintain the stability of the slope.