ABSTRACT

Seepage through an aquifer, the hydraulic conductivity of which varies vertically, is studied using the Dupuit-Forchheimer approximation (Girinskii’s potential) and numerically by FDM-MODFLOW and FEM-HYDRUS-2D. In urban water hydrology, the effect of compaction of the top stratum of an aquifer on the flow rate and the position of the water table (characterized by an integral quantity of the saturated/dry area) is analysed. The area of the saturated zone is evaluated as a function of the conductivity ratio of the two strata, and their thicknesses. Conductivity varying linearly and exponentially is also analytically studied. Boundary-value problems are solved for a linear (nonlinear) ordinary differential equation if the evaporation rate is constant (decreasing exponentially with depth). The MODFLOW and HYDRUS-2D simulations give consistent fields of the piezometric head, pressure head, and Darcian velocity, as well as the water table position, which may have a global minimum (watershed).

摘要

使用Dupuit-Forchheimer逼近法（吉林斯基势），通过FDM-MODFLOW和FEM-HYDRUS-2D数值研究了渗流率在垂直方向变化的含水层的渗流。在城市水文水文中，分析了含水层顶面压实对流量和地下水位（以饱和/干燥区域的整数表示）的影响。根据两个层的电导率及其厚度来评估饱和区的面积。还对电导率线性和指数变化进行了分析研究。如果蒸发速率是恒定的（随深度呈指数下降），则可以解决线性（非线性）常微分方程的边值问题。