第一类越流含水层系统中非完整井附近非达西渗流近似解析解

摘要

The non-Darcian flow to a partially penetrating well in a first type leaky aquifer has been inves-tigated in this paper. Approximate analytical solutions of the drawdowns in the main aquifer were obtained, and an approximate analytical solution for the drawdowns at quasi steady state was also obtained. The flow in the horizontally radial direction is assumed to be non-Darcian and described by the Izbash equation;while the flow in the vertical direction is assumed to be Darcian. A linearization procedure associated with the Laplace transform and the finite Fourier cosine transform are used to solve this model. The results indi-cate that the drawdowns along the vertical direction are symmetric around the well axis if the well screen is located in the center of the aquifer,where the largest drawdown is appeared. At the late stage of pump-ing, the drawdowns decrease with the increase of the aquitard hydraulic conductivity, and the leakage de-creases with the increase of the value of index n in the Izbash equation.%研究了第一类越流含水层系统中非完整井附近非达西渗流问题，得到主含水层抽水井附近水位降深拉氏空间近似解析解及抽水后期近似解析解。抽水井附近主含水层中渗流概化径向渗流和垂向渗流，径向渗流由于流速较大由非达西渗流公式Izbash公式来刻画，垂向渗流由于流速较小用达西定律表示，通过线性化方法简化非达西非线性项，然后结合Laplace变换和有限余弦Fourier变换对水流模型进行求解。结果表明：主含水层中水位降深对称于滤水管中轴线，且在中轴线处最大；在抽水后期，主含水层水位降深随着弱透水层渗透系数的增大而减小，且随着Izbash公式中非达西经验指数n值增大，主含水层得到越流补给的水量减小。