滨海多层含水层系统中海潮引起的地下水位波动

Groundwater Head Fluctuation Induced by Tide in a Coastal Three-layered Aquifer System

通过对一个滨海多层含水层系统的考察,该含水层系统由上、下弱透水层和介于中间的承压含水层组成,海底露头处被淤泥层覆盖。建立了描述该系统中地下水水头随潮汐波动的数学模型,并得到其解析解。该解析解与六个基本参数有关,分别是承压含水层的海潮传播参数,淤泥层的无量纲透水系数,上下弱透层与承压含水层贮水率的比率(无量纲)和上下弱透层的无量纲越流。当这些参数取某些特殊值时,我们的解便化简为前人考虑的几种简单情形对应的解。分析表明,承压含水层中地下水水头波幅是上、下弱透水层贮水率和越流系数的减函数,是淤泥层相对透水系数的增函数;波动相位(时滞)是上、下弱透水层贮水率和越流系数的增函数,是淤泥层相对透水系数的减函数。

This paper investigates a coastal aquifer system consisting of a confined aquifer from up and down by two semi--permeable layers. The suboutcrop of the aquifer is covered by a silt layer. A mathematical model is used to describe this system and the analytical solution of this model is derived. The analytical solution contains six parameters ： the confined aquifer＇s tidal propagation parameter, the dimensionless leakance of the silt layer, the dimensionless storativity ratio and the dimensionless leakage of the upper and lower semi--permeable layers, When these parameters assume special values, the solution becomes several special solutions derived in other situation. The analytical solution indicates that both storage and leakage of the semi- permeable layers and the relative leakance coefficient Of the silt layer have great influences on the groundwater--head fluctuation in the Confined aquifer. The amplitude of the head fluctuation decreases with the storativity and leakage of both semi-permeable layers and increases with the leakance of the silt-layer. However, the positive phase shift （time-lag） of fluctuation increases with the storativity and leakage of both semi-perme able layers and decreases with the leakance of the silt-layer.