定流量下潜水非完整井稳定流计算方法

Method for steady flow of partially penetrating well in phreatic aquifer under constant flow

针对现有潜水非完整井对于不同的管长和淹没状态下有着4种完全不同的理论计算公式,不能很好地解决实际工程中由于潜水位降深不断变化而引起的流量变化问题,将潜水含水层沿潜水位最大降深处分成上下两部分,采用积分变换方法,推导得到可适用于不同管长和淹没状态下的定流量潜水层非完整井的稳定流公式;然后在此基础上,采用Delphi结合Matlab自行开发一个计算程序,对潜水非完整井的井流特点进行分析;最后通过一个基坑降水算例说明了其应用于实际工程的有效性。研究结果表明:①推导得到的潜水非完整井公式可以退化为经典的潜水完整井裘布依公式,并在特殊情况下可得到近似解析解;②自行开发的计算程序可对不同条件下潜水非完整井的阻力系数和流量进行自动快速计算,为潜水非完整井的井流性状分析提供了便利的工具;③将推导出的潜水非完整井稳定流计算公式应用于有隔水围护结构且采用坑内降水方式的基坑工程是可行的。

The existing four totally different theoretical formulae for partially penetrating well in phreatic aquifer with different tube lengths under submerged conditions connot better solve the problem caused by unceasing change of phreatic level drawdown in a real project. The diving layer is divided into two parts along the maximum drawdown of water level, and by dopting the integral transformation method, the formulae for steady flow of partially penetrating well in phreatic aquifer are a obtained under constant flow condition when the tube length and submerged conditions are different. Then on this basis, a program is developed by using Delphi and Matlab to analyze the characteristics of well flow. Finally, it is proved that it can be applied to practical projects through a foundation pit example. The research results show that： （1） the formulae can be degenerated to Dupuit formula for penetrating well in phreatic aquifer under certain circumstances, and approximate analytical solution can be obtained under certain circumstances; （2） the self-developed program can be adopted to calculate resistance coefficient and flow automatically and quickly under different conditions of partially penetrating well in phreatic aquifer, which provides many conveniences for analyzing well flow; and （3） It is feasible to apply the proposed formulae in foundation pits with water-resistance enclosures and dewatering.