第二类越流系统中抽水井附近非达西流近似解析解

An approximate analytical solution for non-Darcian flow near a well in a second kind of leaky aquifer system

该文研究了第二类越流系统中抽水井附近非达西流问题,主含水层中的水流假设为非达西流且方向为水平方向,弱透水层中的水流假设为达西流且方向为竖直方向,假设可以采用Izbash定律描述非达西流。利用线性化方法得到了非达西流情况下的近似解析解并给出了相应的计算算例,以及对计算结果进行了分析。研究结果表明:Izbash定律中的n值越大,在整个抽水时期的水位降深越小;Izbash定律中的k值越大在抽水初期水位降深越大,而在抽水后期水位降深越小;弱透水层的渗透系数在抽水初期对主含水层中的水位降深几乎没有影响,而在抽水后期弱透水层的渗透系数越大,水位降深越小。

Non-Darcian flow near a well in a second kind of leaky aquifer system was investigated analytically in the paper.The flow in the main aquifer was assumed to be non-Darcian in horizontal direction,while the flow in the upper and lower aquitards were assumed to be Darcian in vertical direction.The Izbash equation has been used to describe the non-Darcian flow in this study.An approximate analytical solution has been obtained by using a linearization procedure,and a calculation example has been provided as well as the analysis of the results.The results indicate that a larger power index n in the Izbash equation results in a smaller drawdown during the entire pumping period.A larger k,which is an empirical parameter in the Izbash equation,leads to a greater drawdown at early times while a smaller drawdown at late times.The hydraulic conductivity of the aquitards has little effect on the drawdown in the main aquifer at early times,while larger hydraulic conductivity of the aquitards result in smaller drawdown in the main aquifer at late times.