Hu Li-Tang, Chen Chong-Xi
College of Water Sciences, Beijing Normal University, Beijing 100875, People's Republic of China.
Ground Water. 2008 Jul-Aug;46(4):642-6. doi: 10.1111/j.1745-6584.2008.00436.x.
Concurrent existence of confined and unconfined zones of an aquifer can arise owing to ground water withdrawal by pumping. Using Girinskii's potential function, Chen (1974, 1983) developed an approximate analytical solution to analyze transient ground water flow to a pumping well in an aquifer that changes from an initially confined system to a system with both unconfined and confined regimes. This article presents the details of the Chen model and then compares it with the analytical model developed by Moench and Prickett (1972) for the same problem. Hypothetical pumping test examples in which the aquifer undergoes conversion from confined to water table conditions are solved by the two analytical models and also a numerical model based on MODFLOW. Comparison of the results suggests that the solutions of the Chen model give better results than the Moench and Prickett model except when the radial distance is very large or aquifer thickness is large compared with drawdown.
由于抽水导致地下水抽取，含水层可能会同时存在承压区和非承压区。Chen（1974年、1983年）利用吉林斯基势函数，开发了一种近似解析解，用于分析含水层中向抽水井的瞬态地下水流，该含水层从最初的承压系统转变为既有非承压又有承压状态的系统。本文介绍了Chen模型的详细内容，然后将其与Moench和Prickett（1972年）针对同一问题开发的解析模型进行比较。通过两个解析模型以及基于MODFLOW的数值模型，求解了含水层从承压状态转变为潜水位条件的假设抽水试验示例。结果比较表明，除了径向距离非常大或含水层厚度与水位下降相比很大时，Chen模型的解比Moench和Prickett模型的结果更好。
