摘要
研究了承压含水层中大口径井附近的非达西流,采用线性化方法和Laplace变换得到了无量纲水位降深在拉氏空间下的解析解,采用Stehfest数值逆变换得到了实空间下的水位降深,同时得到了抽水后期和抽水稳定阶段水位降深的解析解。定义了反映非达西流动特征的水力传导度ξ,采用相应的数值解对线性化近似解进行了验证。研究结果表明,在抽水初期,不同ξ值所对应的井筒中的水位降深基本相同,并在双对数坐标下表现为一直线;在抽水后期,无论是在井筒还是含水层中,ξ越大,水位降深越小;在抽水稳定时期,水位降深随距离增大并呈幂函数递增,线性化方法在抽水初期会带来一定误差,而在抽水后期结果比较精确。
The non-Dacian flow towards large-diameter well in confined aquifers was investigated using the method based on the combination of the linearization method and Laplace transform. Both the dimensionless drawdowns inside the well and in the aquifer were obtained with the Stehfest numerical Laplace inversion method and corresponding numerical solution. A dimensionless non-Darcian hydraulic conductivity ξ was introduced to describe the characteristics of flow. The results indicate that the drawdowns inside the well for difrerent ξ approach the same asymptotic value at early stage of drawing, which reflects the effect of well bore storage. In the later stage, the dimensionless drawdowns both inside the well and in the aquifer decreases with the increase of ξ. In the steady drawing period the dimensionless drawdown increases with the increase of dimension less distance and varies following the power function relationship. The comparison with the numerical solution indicates that the approximate analytical solution obtained by linearization method has some errors at early stage, but it becomes smaller in later stage.
出处
《水利学报》
EI
CSCD
北大核心
2009年第7期863-869,共7页
Journal of Hydraulic Engineering
基金
国家自然科学基金项目(50428907,50779067)
教育部新世纪优秀人才支持计划(NCET-05-0125)
教育部创新队计划
北京市重点学科水文学与水资源建设项目
