考虑表皮效应的径向溶质迁移模型以及半解析解  

Semi-analytical solution for radial solute transport model with skin effect

作　　者：文章 李旭 Wen Zhang;Li Xu(School of Environmental Studies,China University of Geosciences(Wuhan),Wuhan 430078,China)

机构地区：[1]中国地质大学(武汉)环境学院,武汉430078

出　　处：《地质科技通报》2020年第1期60-66,共7页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(41772259,41830862)。

摘　　要：径向示踪试验是一种非常有效的获取含水层弥散参数的试验方法,但传统径向示踪试验很少考虑抽水井附近的表皮效应(由于钻井施工工艺所导致抽水井附近一定区域水力性质发生变化).建立了考虑表皮效应的单井注入示踪试验模型,并利用Lapalce变换以及数值逆变换获得了该模型的半解析解.系统分析了表皮区域水力性质对示踪试验穿透曲线的影响规律.研究结果表明:表皮区域的弥散度越大,穿透曲线早期的浓度越高,且峰值越高;表皮孔隙度越大,穿透曲线早期浓度越低,后期浓度越高;此外,散度差异也会导致浓度分布曲线在表皮区域与含水层界面处发生突变.总之,表皮效应对径向溶质迁移产生了较大的影响,有必要将表皮效应考虑到径向示踪试验中去.Radial tracer test is one of the most effective ways to estimate aquifer transport parameters.However,traditional tracer tests usually neglect skin effect near a pumping well,due to extensive well de-velopment resulting in anomalous hydrogeological properties.A semi-analytical model for a confined aquifer was developed to analyze the effects of skin of hydrogeological properties on breakthrough curves.The La-place transform and numerical inverse Laplace methods were used to solve the model.The results indicate that a larger dispersivity in the skin zone results in higher values of breakthrough curves(BTCs)at the early injection stage,and higher peak values of BTCs;however,larger effective porosity in the skin zone re-sults in lower values of the BTCs at the early injection stage but generates higher values at the late stage;besides,an abrupt change for the spatial concentration distribution was observed at the interface of the skin and aquifer formation zones due to the change of dispersivity in the skin zone.The general conclusion is that the possible impacts of skin on radial solute transport are significant and should be taken into consideration in tracer injection tests.

关 键 词：径向溶质迁移 表皮效应 示踪试验 对流弥散方程 

分 类 号：X143[环境科学与工程—环境科学]