双层结构土质边坡降雨入渗过程及稳定性分析  

Rainfall infiltration process and stability analysis of two-layered slope

作　　者：韩同春[1] 黄福明[1] 

机构地区：[1]浙江大学岩土工程研究所,浙江杭州310058

出　　处：《浙江大学学报（工学版）》2012年第1期39-45,共7页Journal of Zhejiang University：Engineering Science

摘　　要：针对天然土质边坡由于地质和人为因素的作用,通常呈现一定层状结构这一问题,基于Moore水质量分数模型,结合降雨强度,将双层土边坡的降雨入渗过程划分为不同阶段.以一基岩型土质边坡为例,利用渗流有限元程序SEEP/W分析双层土边坡降雨入渗全过程.分析结果验证了双层土边坡降雨入渗过程的不同阶段:当降雨强度<表层土体的渗透系数时,初始降雨入渗率=降雨强度;当表面发生积水后降雨入渗率急剧下降,最终等于基岩的渗透率;降雨强度越大,表面发生积水的时间越短;当考虑平行边坡的渗流时,边坡的稳定安全系数在湿润锋到达基岩接触面时发生突变,湿润锋到达接触面时引起接触面的孔隙水压力上升是滑坡破坏的主要原因.得到降雨强度、降雨持续时间与湿润锋深度的相关曲线.研究成果揭示了降雨入渗对双层土边坡的破坏机制.Natural soil slopes often consist in two or more soil layers due to the geological and human factors.The rainfall infiltration process of two-layered slope was divided into several stages in order to solve the problem based on Moore infiltration model.Taking a soil slope underlain by bedrock for example,the infiltration process was analyzed using SEEP/W program.Results show that rainfall infiltration process of the slope can be divided into different stages.When rainfall intensity is smaller than hydraulic conductivity of surface soil,initial infiltration rate is equal to rainfall intensity.Infiltration rate dramatically drops when surface ponding takes place,which is equal to permeability of bedrock at last.The larger the intensity of rainfall is,the shorter the time of surface ponding is.The stability factor sharply changes when wetting font reaches subsurface.An increase of pore-water pressure at subsurface when wetting font reaches is the main reason of slope failure.The relation between rainfall intensity,duration and depth of wetting font was calculated.Results revealed the mechanism of rainfall induced failure of two-layered slope.

关 键 词：边坡 降雨 入渗率 Moore模型 安全系数 

分 类 号：TU443[建筑科学—岩土工程]