多层土质边坡入渗的水流方向演变机理

为研究多层土边坡内入渗雨水方向演变规律，建立均质和多层土质边坡模型，依据VG模型的多土层边坡含水率与基质吸力的控制方程，结合饱和区成形，研究了入渗雨水方向的时空演变特征及影响因素，以及水流方向与有效应力的联系.分析表明:水平方向的基质吸力差决定了水流方向，基质吸力沿水平方向的变化率决定了水流水平方向增速；饱和区成形是垂直流产生的必要条件；降雨停止坡面浅层0~1.3m内迅速产生下坡向水流，深层下坡向水流产生滞后；渗透性差异大的土层交界面上极易产生剧烈的水平渗流；上坡向水流的产生伴随着有效应力降低.

Mechanism of Water Flow Migration Evolution in Multi-layer Soil Slope During Rainfall Infiltration

In order to study the law of water flow migration in multi-layer soil slope， the homogeneous soil slope model and the multi-layer soil slope model were established. The temporal and spatial characteristics and influencing factors of water flow migration were explored， with the development of saturated-zone taken into account， based on the governing equation of moisture content and matrix suction in multi-layer soil slope derived from the VG model. The relationship between water flow migration and effective stress was also studied. It is found that the difference in the matrix suction in the horizontal direction decides the change of water flow migration mode and the rate of change of matrix suction along the horizontal direction determines the rate increment of water flow horizontal direction. The formation of the saturated-zone is a necessary condition for forming the vertical water flow. After the rainfall stops， the down-slope water flow is rapidly generated only in the shallow layer of 0~1.3m， with the forming of down-slope water flow in deep area lagging behind. The horizontal water flow at the interface of two layers of soil with large differences in permeability changes sharply， and the forming of up-slope water flow is always accompanied with the decrease of effective stress.