雨洪资源人工回灌数值模拟模型研发

Rainfall flood resources artificial recharge is an important means to solve the problem of groundwater overdraft and water shortages, which is a effective model for water united dispatching. Physical blockage is a major problem faced by artificial recharge of rainwater resources, and there have a few quantitative research for clogging mechanism. So, non-homogeneous suspended particulate filter theory as a starting point, in-depth study of artificial recharge rainfall flood resources physical blockage mechanism has important practical significance and scientific value.By with the filtering theory for heterogeneity suspended particles and the modeling experience of dimensional numerical simulation model, quantitative study of artificial recharge clogged rain floods process. Combined rainfall flood artificial recharge physical model, studies to determine the method proposed under certain water conditions easy to plug particles. The project will be a breakthrough in the study of artificial recharge of rainfall flood resources physical blockage mechanism and method of determining the easy clogging particles, the results of this research will further reveal clogging process of rainfall flood resources artificial recharge, which will provide technical support for prevention, governance and repair on clogging in rainfall flood resources artificial recharge.

雨洪资源人工回灌是解决地下水超采问题，缓解水资源压力的重要手段，是多水源联合调蓄利用的有效模式。物理堵塞问题是雨洪资源人工回灌面临的主要问题，且目前堵塞机理的定量化研究还较为薄弱，因而通过建立适用于雨洪资源人工回灌堵塞过程的数值模拟模型，深入其堵塞机理具有重要的现实意义和科研价值。本项目将以前期工作建立的非均质悬浮颗粒过滤理论及二维雨洪水人工回灌理想数值模拟模型建模经验为基础，结合室内雨洪水人工回灌物理模型，研发适用于雨洪水人工回灌工作的三维非均质水源回灌模拟模型，定量化研究雨洪水人工回灌的堵塞过程；结合雨洪水人工回灌数值模拟模型，研究提出特定水源条件下易堵塞颗粒的确定方法。该项目将在雨洪资源人工回灌物理堵塞机理和易堵塞颗粒的确定方法的研究方面有所突破，其成果将进一步揭示雨洪资源人工回灌的堵塞过程，将为雨洪资源人工回灌堵塞问题的防控、治理和修复提供技术支撑。

本项目搭建了用于研究雨洪水回灌中悬浮颗粒堵塞的物理模型，并开展了多次试验研究工作。基于物理模型，分析了含水层受堵塞的特征，渗透系数分布的变化规律以及雨洪水的浓度变化等，试验结果表明堵塞总是优先发生在含水层的表层，在渗透系数为20m/d的孔隙介质中，浓度为30mg/L的雨洪水流经3m左右长度时，悬浮颗粒浓度则衰减90%以上，溶液中失去的悬浮颗粒均被含水层捕获；在物理模型的基础上，编写了二维雨洪水人工回灌数值模拟模型程序，该程序由模型相关参数输入、参数合理性自检测、目标变量数值后差分解算、同步解算结果图示等模块组成，并基于物理模型对数值模拟结果进行了验证，对比验证结果表明，研发的数值模拟模型可较好的模拟雨洪水回灌中堵塞的发生过程，均体现了表层堵塞的特征，但悬浮颗粒浓度的计算值和实测值有一定的误差，主要体现在出流浓度上，由数值模拟模型模拟计算的出流浓度为5mg/L左右，而实测结果小于该值；在此基础上，分析了并建立了雨洪水人工回灌易堵塞悬浮颗粒识别方法，考虑悬浮颗粒非均质性时，易堵塞悬浮颗粒的评估不仅受颗粒大小的影响，还受回灌原水中的颗粒分布影响。