极端降雨对边坡土体强度的影响及其稳定性分析

Stability and Soil Strength Analysis of Alope under Extreme Rainfall

降雨是影响边坡稳定性的重要因素。在分析重庆市1951—2015年降雨特征的基础上,以重庆市某高速公路高填方路基边坡为研究对象,分析了极端降雨对边坡土体基质吸力、强度和边坡稳定性的影响。结果表明:在降雨的初期,极端降雨对边坡土体基质吸力的影响较大,随着入渗时间的持续,基质吸力呈现出降-升-降特征;当土体入渗稳定时,基质吸力趋于稳定;降雨入渗对边坡土体内聚力有小幅增大作用,对内摩擦角则具有减弱作用,其平均值可降为初始内摩擦角的0.68倍;降雨入渗降低了边坡的稳定系数,但降雨入渗稳定后,边坡的稳定系数趋于稳定。

Rainfall is an important factor affecting slope stability.Based on the analysis of the rainfall characteristics of Chongqing from 1951 to 2015,and taking the high fill subgrade slope of a highway in Chongqing as the research object,the influence of extreme rainfall on matrix suction,soil strength and stability are studied.The results indicate that the influence of extreme rainfall on soil matrix suction of slope is great at the beginning of rainfall,and with the continues of infiltration time,the matric suction of soil exhibits the characteristics of down,up and down.When the rainwater infiltration is stable,the matrix suction is gradually stable.The cohesion of soil showed a slightly increasing and the internal friction angle can be weakened because of rainfall infiltration.The average value of internal friction angle can be reduced to 0.68 times of the initial internal friction angle.Rainfall infiltration can reduce stability coefficient of slope.When the rainfall infiltration tends to be stable,the stability coefficient of slope tends to be stable.