考虑井周堵塞效应的定水头非完整回灌井流模型  

Model for well hydraulics of constant-head injection using a partially penetrating well considering clogging in well vicinity

作　　者：李炯 李明广[1,2] 詹红兵 陈锦剑 夏小和[1,2] LI Jiong;LI Mingguang;ZHAN Hongbing;CHEN Jinjian;XIA Xiaohe(Department of Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure,Shanghai 200240,China;Department of Hydraulic Engineering,Tsinghua University,Beijing 100084,China;Department of Geology&Geophysics,Texas A&M University,Texas 77840,USA)

机构地区：[1]上海交通大学土木工程系,上海200240 [2]上海市公共建筑和基础设施数字化运维重点实验室,上海200240 [3]清华大学水利水电工程系,北京100084 [4]德克萨斯农工大学地质与地球物理系,德克萨斯77843

出　　处：《岩土工程学报》2024年第1期207-215,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(42077166);上海市科委社发项目(21DZ1204300);国家重点研发计划项目(2021YFC3201203)。

摘　　要：针对传统定水头井流模型无法反映井周含水层堵塞对含水层渗流响应影响的问题,在假设井周含水层渗透系数在堵塞作用下随时间呈指数形式衰减的基础上,建立了考虑堵塞效应的定水头非完整回灌井流模型。通过对模型进行变量代换、Lapλace变换和有限余弦Fourier变换及其逆变换,推导了定解问题在Lapλace空间的解,并采用Stehfest数值逆变换方法得到了实时空间内的半解析解。参数分析结果表明,较小的渐近渗透系数Kr,∞会减小回灌过程中回灌流量和水头抬升,并降低含水层的拟稳态渗流响应,而较大的渗透系数衰减指数λ仅降低了渗透系数衰减过程中水头抬升和回灌流量,并不影响含水层达到拟稳态时的渗流状态;因Kr,∞和λ不同引起的水头差沿径向距离先增大后减小,在井周堵塞区与主含水层交界面达到最大值;回灌堵塞使得水头抬升分布在井周堵塞区与主含水层交界面上存在明显的折点,并造成含水层水头在抬升过程中存在显著的下降阶段,上述特征可为回灌堵塞评估与预测提供参考。To address the issue that the traditional models of well hydraulics for constant-head tests(CHTs)fail to reflect the effects of the clogging in well vicinity on groundwater flow dynamics,a semi-analytical model of the groundwater hydraulics in well vicinity is developed for CHTs using partially penetrating wells.A combination of variable substitution,Laplace transform and finite Fourier cosine transform is used to develop the solutions for the proposed model in the Laplace domain.Then,the solutions in the real-time domain are obtained using the Stehfest numerical Laplace inversion method.A parametric study of the developed solution indicates that a smaller asymptotic hydraulic conductivity Kr,∞leads to the smaller hydraulic head increment s and the less injection flux Q and reduces the quasi-steady flow dynamics of the recharged aquifer,while a larger permeability reduction exponentλdecreases s and Q only in the middle stage of the injection tests but has few effects on the quasi-steady flow dynamics.The hydraulic head difference due to various values of Kr,∞and λ first increases and then decreases with the radial distance and reaches its maximum value at the interface of the clogging region and the formation.The clogging in well vicinity results in an obvious inflection point at the outside boundary of the clogging region on the distribution curve of s and leads to an apparent decreasing stage of the history curve of s,which can offer theoretical reference for the evolution and prediction of the clogging development.

关 键 词：回灌堵塞 定水头回灌 非完整井 井流力学 半解析解 

分 类 号：TU42[建筑科学—岩土工程]