经典地下水抽水试验水文地质参数解算方法

Calculation Method for Hydrogeological Parameters of Classic Groundwater Pumping Test

摘要: 地下水分潜水及承压水，抽水试验分稳定流及非稳定流抽水试验。随着我国建设工程的迅速发展，基坑工程规模越来越大，基坑深度越来越深，基坑降水对周边环境的影响越来越大，对查明场地水文地质条件及水文地质参数提出了更高的要求，通常需要进行抽水试验以查明含水层的水文地质参数。探索利用现代计算工具，对经典地下水稳定井流及Thies非稳定井流抽水试验进行水文地质参数解算具有一定意义。稳定流解算较为简单，可用Excel线性回归方法进行求解。非稳定流解算方法较为复杂，数值求解需采用非线性及最优化方法。Theis井函数计算，利用变量代换消除了被积函数奇点，将无限积分截断为有限积分，积分截断误差 < 10⁻¹⁵。Theis非稳定井流水文地质参数的反演求解，使用Mathcad数学软件求解局部最优解，利用1stOpt最优化专业软件求解全局最优解，两者最优化解算结果非常接近。

Abstract: The underground water consists of phreatic water and confined water, and pumping tests are divided into stable flow and unsteady flow pumping tests. With the rapid development of construction projects in our country, the scale of foundation pit engineering is getting larger and the depth of foundation pits is getting deeper. The impact of foundation pit dewatering on the surrounding environment is increasing, which puts higher requirements on identifying the hydrogeological conditions and parameters of the site. Usually, pumping tests are needed to determine the hydrogeological parameters of the aquifer. Exploring the use of modern computational tools for hydrogeological parameter calculation in classic groundwater stable well flow and Thies unsteady well flow pumping tests has certain significance. Stable flow calculation is relatively simple and can be solved using Excel linear regression method. The method for solving unsteady flow is relatively complex, and numerical solutions require the use of nonlinear and optimization methods. The well function calculation utilizes variable substitution to eliminate singular points in the integrand function, truncating infinite integrals into finite integrals with an integration truncation error of < 10⁻¹⁵. The inversion solution of the hydrogeological parameters of unstable well water flow is carried out by using Mathcad mathematical software to solve the local optimal solution and 1stOpt optimization professional software to solve the global optimal solution. The results of the two optimal solutions are very close.