不稳定承压-无压完整井流滞后给水机理及计算模型研究

The research is aimed at investigating the transient confined-unconfined flow towards a fully penetrating well in a confined aquifer. Studies of the analytical and the numerical solutions for the transient confined-unconfined flow have been carried out based on the Theis assumptions and the Dupuit assumptions since 1970s. However, these former solutions are identified to theoretically ignore the vertical flow component and delay response during the transient confined-unconfined conversion. To improve the diagnostic and quantitative analysis of the transient confined-unconfined flow in a confined aquifer, a new solution by considering the effects of the vertical flow and the effect of delay response is proposed, which can be further used to (1) reveal the effects of aquifer anisotropy on the drawdown behaviors of the transient confined-unconfined flow; (2) investigate the mechanisms of delay response. The research provides hydrogeologists with advancing understanding of the transient confined-unconfined flow processes in response to pumping from a confined aquifer. The results will be useful for the sustainable management of the groundwater resources in mining areas.

在无限各向异性的孔隙承压含水层中，抽水形成的不稳定承压-无压井流是煤矿区矿井疏干过程中的经典地下水动力学问题。许多学者基于泰斯井流假设和裘布依假设，提出了多种不稳定承压-无压完整井流计算模型。然而，这些传统模型对于无压区垂直流和无压区滞后给水作用对不稳定承压-无压完整井流渗流场的影响考虑不足，也限制其在实际工程中的应用。针对上述不足，本研究拟提出考虑无压区垂直流和无压区滞后给水作用的不稳定承压-无压完整井流模型，并进一步（1）揭示含水层各向异性对不稳定承压-无压井流降深-时间特征曲线的影响规律；（2）明确无压区饱和带重力给水作用和无压区非饱和带滞后给水作用机理，合理解释滞后疏干现象。本研究旨在揭示不稳定承压-无压完整井流的渗流场特征，提供具有科学意义的理论基础和应用模型，为矿区疏干工程的合理设计和矿区地下水资源保护提供科技支撑。

本项目针对煤矿开采中出现的不稳定承压-无压完整井流问题以及相应的水力学响应特性进行了理论上得探讨和数学模型的建立，取得了较为重要的进展。本项目（1）考虑含水层各向异性，基于Moench滞后给水理论引入饱和带承压-无压转换界面定水头和定流量边界条件和非饱和带无压流转换界面定水头边界条件，提出不稳定承压-无压完整井流精算模型；（2）考虑非完整井的影响，基于Neuman和Tartakovsky滞后给水理论，建立不稳定承压-无压非完整井流计算模型；（3）考虑高速抽水引起的非线性渗流现象，基于Izabash理论，建立二维非达西承压-无压完整井流计算模型。基于上述模型进一步探讨滞后给水效应、非完整井和非线性渗流作用对承压-无压井流的影响机理。研究成果可为矿区疏干工程的合理设计和矿区地下水资源保护提供了具有科学意义的理论基础和应用模型。