论文部分内容阅读
抽水井附近由于流速过快往往发生非达西流,而远离抽水井随着流速下降又变为达西流.为了描述这些特征,建立了承压含水层中非完整井附近“非达西-达西”两区渗流模型,即距离抽水井较近的区域由于流速较快假设发生非达西渗流,并利用Izbash公式刻画,而距离抽水井较远由于流速较慢假设仍然满足达西定律,含水层中垂向流速较小也利用达西定律描述.通过线性化近似方法结合Laplace变换和有限Fourier余弦变换对模型进行了求解,分析探讨了该两区模型下水位降深曲线特征.结果表明:抽水初期,非达西渗流区域水位降深与全非达西渗流模型结果吻合,而抽水后期两区模型非达西渗流区域的水位降深与全达西模型水位降深基本一致,但大于全非达西渗流模型的水位降深;抽水初期,两区模型中达西渗流区域的水位降深比全达西渗流模型结果大,但比全非达西渗流模型结果小;对不同时间的水位降深随井距变化曲线分析发现非达西渗流区域水位降深随Izbash公式中的幂指数n增大而减小,而在达西渗流区域水位降深基本不受n值的影响.研究成果对非完整井抽水试验参数反演具有重要理论意义.
In order to describe these characteristics, a non-Darcy flow near confined aquifers near non-intact wells was established near the pumping wells because of the non-Darcy flow which occurs too fast due to the rapid flow rate, Darcy "two-zone seepage model, that is, in a region close to the pumping well, non-Darcy seepage flow is assumed because of the fast flow rate and is characterized by Izbash formula and far away from the pumping well due to Darcy’s law , And the vertical flow rate in aquifer is also described by Darcy’s law.The linear approximation method combined with Laplace transform and finite Fourier cosine transform is used to solve the model.The characteristics of the water level drop curve under the two models are analyzed and discussed.Results The results show that in the early stage of pumping, the water level drop in the non-Darcy seepage zone agrees well with that of the non-Darcy flow model. However, the deepening of the water level in the non- In the early stage of pumping, the water level drop in the Darcy flow area in the two-zone model was larger than that in the whole Darcy flow model. However, compared with the non-Darcy flow model junction It is found that the drop of water level in the non-Darcy seepage area decreases with the increase of the power index n in the Izbash formula, while the water level drop in the Darcy seepage area is basically unaffected the value of n.The research results have important theoretical significance for the inversion of test parameters of pumping in incomplete wells.