考虑淤泥层弹性储水的滨海承压含水层中海潮引起的地下水头波动

Tide-induced Head Fluctuations in a Coastal Aquifer:Effects of the Elastic Storage and Leakage of the Sediment on the Seafloor

综合考虑了海底淤泥层的弹性储水系数、海潮荷载效应和渗透性,对海底露头处具有淤泥层的滨海承压含水层系统中海潮引起的水头波动进行分析,给出了相应的数学模型,并推导出其解析解,讨论了淤泥层弹性储水对于水头波动的影响。分析表明,当淤泥层的厚度或弹性储水系数较小时,或者其渗透性较好时,可以忽略其弹性储水效应,从而把整个淤泥层简化为第三类边界条件来处理。文章还考虑了承压含水层和淤泥层中可能存在的垂向流动,对垂向剖面二维地下水流动方程进行了数值模拟,将二维数值解与忽略垂向流动的一维解析解进行了比较,结果表明该含水层系统的垂向流动是可以被忽略的。

This paper considers the effects of the elastic storage, the tidal loading efficiency and leakage of the seabed silt-layer on the tide-induced head fluctuations in a coastal confined aquifer. A mathematic model and its analytical solution are presented. The influences of the elastic storage of the silt-layer on the tidal groundwater head fluctuation are analyzed and discussed. It is found that for silt-layers with small thickness or elastic storage or with large leakage, the effect of the elastic storage of the silt-layer is negligible. In this case, the silt-layer can be modeled as the third kind of boundary condition （Robin type）. Two-dimension numerical simulations are also conducted to consider both the vertical and horizontal flows in the confined aquifer and silt- layer. Comparison with the one-dimensional analytical solution which ignored the vertical flow indicates that the vertical flow is negligible .