地下水监测网优化布井方法研究

发布时间：2018-03-31 01:10

本文选题：顺义区　切入点：地下水监测网　出处：《河南大学》2015年硕士论文

【摘要】：地下水监测网优化模型是一项经济实用、科学可靠的地下水管理技术。结合数值模拟的地下水监测网多目标模拟优化模型能够最大限度提高监测系统可靠性,得到监测井数量最小的监测系统,并确定监测井的位置,从而使得监测费用最小化。本论文以北京市顺义区一养猪场氨氮污染地下水区域为例,首先利用GMS软件包搭建了地下水水流模型和地下水氨氮溶质运移模型;再利用Monte Carlo分析法分析了水流模型和溶质运移模型的不确定性参数,再又利用Monte Carlo分析结果的基础上构建了监测井影响半径的概率密度分布函数并代入地下水监测网优化模型,从而构建了研究区域地下水监测网多目标模拟优化模型;再用NSGA-II算法建立模拟优化模型多目标函数之间的权衡关系、最大化监测系统的可靠性,确定监测井的数量和位置;最后对模拟优化模型的优化结果进行分析,完成监测井优化。论文得到以下结论:1、地下水数值模型得到的氨氮污染羽边界与本文所列水文地质参数正相关,较大的降雨入渗系数和池塘入渗补给系数会加强氨氮污染物对地下水的垂向补给,渗透系数则会加大氨氮在地下水中的扩散,这使得模拟得到的污染羽边界扩大,反之亦然。不同的氨氮环境控制标准,也会影响污染羽的边界。污染羽边界也是监测井数量决定性因素之一。2、基于数值模型的地下水监测网多目标模拟优化模型构建的监测系统能够更加真实地反映复杂地下水环境,充分结合场地资料,避免了模型与实际水文地质信息脱节。NSGA-II算法对模拟优化模型的求解能够保证多个目标函数的全局收敛,防止多个不确定性参数造成的局部收敛,本论文的两个目标函数分别在运行10代和20代之后全局收敛。3、NSGA-II算法结果表明,为使得监测系统的可靠性目标最大化,NSGA-II优化的监测井数量为3口,监测井位置分别为19号、23号和39号监测井,最佳监测井的位置应分别位于氨氮污染羽的上中下游,并呈三角形分布,3口监测井的监测系统最大可靠性目标为76.8%。降低环境控制标准,污染羽的边界会扩散到农田用地以外的区域,此时应建立4口监测井,监测井位置分别为19号、20号、23号和39号。
[Abstract]:The optimization model of groundwater monitoring network is an economical, practical, scientific and reliable groundwater management technology. The multi-objective simulation optimization model of groundwater monitoring network combined with numerical simulation can maximize the reliability of the monitoring system. A monitoring system with the smallest number of monitoring wells is obtained and the location of the monitoring wells is determined to minimize the monitoring costs. This paper takes the ammonia nitrogen pollution area of a pig farm in Shunyi District of Beijing as an example. Firstly, the groundwater flow model and ammonia nitrogen solute transport model are built by using GMS software package, and the uncertain parameters of flow model and solute transport model are analyzed by Monte Carlo method. On the basis of the results of Monte Carlo analysis, the probability density distribution function of the influence radius of monitoring wells is constructed and the optimization model of groundwater monitoring network is put forward, thus the multi-objective simulation optimization model of groundwater monitoring network in the study area is constructed. Then the NSGA-II algorithm is used to establish the tradeoff between the multi-objective functions of the simulation optimization model, to maximize the reliability of the monitoring system, to determine the number and location of the monitoring wells, and finally to analyze the optimization results of the simulation optimization model. In this paper, the following conclusion is drawn: 1. The boundary of ammonia nitrogen pollution plume obtained by numerical model of groundwater is positively related to the hydrogeological parameters listed in this paper. The larger rainfall infiltration coefficient and pond infiltration recharge coefficient will strengthen the vertical recharge of ammonia nitrogen pollutants to groundwater, while the permeability coefficient will increase the diffusion of ammonia nitrogen in groundwater, which makes the simulated pollution plume boundary expand. Different Ammonia-nitrogen Environmental Control Standards, The pollution plume boundary is also one of the decisive factors in the number of monitoring wells. The monitoring system based on numerical model and multi-objective simulation optimization model of groundwater monitoring network can reflect the complex groundwater environment more truthfully. Based on the site data, the solution of the simulation optimization model by using the NSGA-II algorithm can ensure the global convergence of multiple objective functions, and prevent the local convergence caused by many uncertain parameters, so as to avoid the disconnection between the model and the actual hydrogeological information. The results of the two objective functions in this paper show that the number of monitoring wells optimized by NSGA-II in order to maximize the reliability goal of the monitoring system is 3, which is the result of the global convergence of NSGA-II algorithm after 10 and 20 generations of operation, respectively. The location of the monitoring wells is 19, 23 and 39, respectively. The best monitoring wells shall be located in the upper, middle and lower reaches of the ammonia pollution plume, The maximum reliability target of the monitoring system for 3 monitoring wells distributed in a triangle is 76.80.The boundary of pollution plume will spread to the area outside farmland land when the environmental control standard is lowered, and 4 monitoring wells should be established at this time. The location of the monitoring well is 19, 20, 23 and 39, respectively.
【学位授予单位】：河南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641.7

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