降雨条件下坡积土边坡暂态饱和区形成机理及分布规律

发布时间：2018-09-07 17:01

【摘要】：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。
[Abstract]:Rainfall is one of the most common external factors causing slope instability. The infiltration of Rain Water will decrease the shear strength parameters of the soil, but will also lead to the increase of the serious soil mass and the decrease of the matrix suction, which will eventually lead to the instability of the slope. The study of the seepage process of Rain Water in the slope has become the premise of analyzing the slope stability under rainfall conditions. Based on the finite element numerical simulation method, the seepage process of Rain Water in soil is simulated, focusing on the formation, distribution and dissipation characteristics of transient saturated region of slope under rainfall, and describing the internal moisture content and matrix suction of the slope during the process. The variation of hydraulic gradient. The results show that the main reason for the formation of transient saturated zone is that the amount of rain seeping under the wetting front is less than the amount of rainfall infiltration, which makes the water content in the soil increase, and the formation of transient saturated zone and the intensity of rainfall. Rainfall time is closely related to the formation time of transient saturation zone, Rain Water infiltration depth, soil surface volume water content and rainfall intensity. The whole process of formation and development of transient saturated zone to dissipate the rise of groundwater level is clearly described. From this process, the design of slope drainage measures is worth considering.
【作者单位】：长沙理工大学特殊环境道路工程湖南省重点实验室;长沙理工大学交通运输工程学院;长沙理工大学土木与建筑学院;
【基金】：国家自然科学基金(51508040、51508042、51508079、51678074) 湖南省自然科学基金(2016JJ3010) 湖南省重点研发计划(2016SK2023) 长沙理工大学特殊环境道路工程湖南省重点实验室开放基金(kfj150504)~~
【分类号】：TU43

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