| 承压含水层中非完整井附近“非达西-达西”两区渗流模型近似解析解 |
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| 引用本文： | 文章,刘凯,陈晓恋.承压含水层中非完整井附近“非达西-达西”两区渗流模型近似解析解[J].地球科学,2015,40(5):918-924. |
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| 作者姓名： | 文章 刘凯 陈晓恋 |
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| 作者单位： | 1.中国地质大学环境学院，湖北武汉 430074 |
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| 基金项目： | 国家自然科学基金项目，国家重点基础研究发展计划项目，中央高校基本科研业务费专项基金项目 |
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| 摘 要： | 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.
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| 关 键 词： | 非达西流 两区模型 非完整井 线性化 地下水 |
| 收稿时间： | 2014-09-15 |
Approximate Analytical Solutions for Two-Region Non-Darcian Flow to a Partially Penetrating Well |
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| Wen Zhang,Liu Kai,Chen Xiaolian.Approximate Analytical Solutions for Two-Region Non-Darcian Flow to a Partially Penetrating Well[J].Earth Science-Journal of China University of Geosciences,2015,40(5):918-924. |
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| Authors: | Wen Zhang Liu Kai Chen Xiaolian |
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| Abstract: | Non-Darcian flow is likely to occur in the region near a pumping well because of high velocities, while flow becomes Darcian again in the region far away from the pumping well as the velocity decreases. To describe these characteristics, a two-region non-Darcian flow model toward a partially penetrating well is developed in this study. The flow in the region near the pumping well is assumed to be non-Darcian which can be described by the Izbash equation. The flow in the region far away from the pumping well was assumed to be Darcian as well as the vertical flow due to the low velocities. A linearization procedure associated with the Laplace transform and finite cosine transform is used to work out such two-region non-Darcian flow model. The characteristics of the drawdowns under such flow conditions are examined. It is concluded that: (1) the drawdown in the non-Darcian flow region is the same as that of the fully non-Darcian flow model at early times, and it is the same at that of the fully Darcian flow model and larger than that of the fully non-Darcian flow model at late times. (2) the drawdown in the Darcian flow region is larger than that of the fully Darcian flow model and smaller than that of the full non-Darcian flow model at early times; (3) the drawdown-distance behavior indicates that the drawdown in the non-Darcian flow region increases as the power index n in the Izbash equation increases, while the value of n has a little effect on the drawdown in the Darcian flow region. The results of this study will be of great theoretical significance for the aquifer parameters estimation with the pumping test data in a partially penetrating well. |
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| Keywords: | non-Darcian flow two-region model partially penetrating well linearization ground water |
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