论文部分内容阅读
降雨是引起坡积土边坡失稳的最常见外部因素之一。雨水的入渗在引起土体抗剪强度参数降低的同时,还将导致土体重度的增加、基质吸力的降低,最终造成边坡的失稳。开展雨水在边坡内部的渗流过程研究已成为分析边坡在降雨条件下稳定性的前提。基于有限元数值模拟方法,进行了雨水在土体中渗流过程的模拟,着眼于降雨条件下边坡暂态饱和区的形成、分布及消散特征,描述了该过程中边坡内部含水率、基质吸力、水力梯度的变化规律。结果表明:暂态饱和区形成的主要原因是土体中向湿润锋下方渗出的雨水量小于降雨入渗补给量,从而使得土体中的含水率累积升高;暂态饱和区的形成与降雨强度、降雨时间具有十分密切的关系,暂态饱和区形成时间、雨水入渗深度、土体表面体积含水率大小分别与降雨强度存在函数关系;清晰描述了暂态饱和区形成发展消散地下水位升高的全过程,从该过程看,边坡排水措施的设计值得思考。
Rainfall is one of the most common external factors that cause slope landslide instability. The infiltration of rain water will cause the decrease of shear strength parameters of soil, meanwhile it will lead to the increase of soil mass, the decrease of matric suction and eventually the instability of slope. The research on the seepage process of rainwater inside the slope has become a prerequisite for analyzing the stability of the slope under rainfall conditions. Based on the finite element numerical simulation method, the seepage process of rainwater in soil was simulated. The formation, distribution and dissipation characteristics of transient saturated zone under rainfall were described. The internal moisture content, , Hydraulic gradient changes. The results show that the main reason for the formation of transient saturated zone is that the amount of rainwater infiltrating below the wetting front in the soil is less than that of the rainfall infiltration, so that the water content in the soil increases cumulatively. The formation of the transient saturated zone Rainfall intensity and rainfall time. The formation time of transient saturated zone, the depth of rainfall infiltration and the volumetric water content of soil surface have a function relationship with rainfall intensity respectively. The formation and development of transient saturated zone is clearly described as the dissipation of groundwater table The whole process of raising, from the process, the design of slope drainage measures worth considering.