含弱透水夹层边坡非饱和渗流数值模拟研究

A Numerical Simulation of Unsaturated Seepage in Slopes with Low-Permeability Layers

夹层结构或互层结构是常见的坡体结构形式,软弱夹层或岩层通常具有较弱的透水性,对边坡地下水分布及渗透特性具有重要影响。基于水体质量守恒方程及V-G模型,采用PVI方法对含夹层边坡进行非饱和渗流模拟。通过实验对比,验证了该算法的可靠性。现场尺度的模拟结果表明,含低渗透性夹层的边坡易在夹层处表现出地下水分层的现象,且夹层的渗流特性和发育程度直接影响该区域地下水的分布情况:随着夹层非饱和参数α的增大(或n的减小),夹层与邻近岩土体渗透系数比的减小,夹层厚度与高度的增加,地下水分层现象更加显著。研究揭示了含夹层边坡地下水特殊分布模式,也对类似结构岩土体的非饱和水力参数确定有一定的参考价值。

The interlayer structure or multi-layer structure is a common form of slope structure. The weak interlayer or rock layer is usually of low permeability, which has a significant influence on the groundwater distribution and permeability characteristics of the slope. Based on the water mass conservation equation and the V-G model, the unsaturated seepage of the layered slope is simulated with the PVI method. The reliability of the algorithm is verified by comparing the experimental results. The site-scale simulation results show that the slope with impeding layers can easily cause the distribution of groundwater in multiple layers. And the seepage properties and development degree of the interlayer directly affect the distribution of groundwater in the region. Specifically, the increase in the parameter α(or the decrease in n), the decrease in the permeability ratio between interlayer and adjacent rock and soil and the increase in its thickness and elevation cause more significant distribution of stratified groundwater. This study reveals a special distribution pattern of groundwater in layered slopes, which serves as a reference for determining the unsaturated hydraulic parameters of similar geological structures.