基于MODFLOW2005的Ghost-node方法的二级局部网格加密技术的研究与应用
发布时间：2018-07-25 06:34
【摘要】：华北平原地区70%以上用水靠地下水,补给不足和长期严重超采,导致地下水资源量锐减、地面沉降等环境地质灾害频发,已成为制约可持续发展的瓶颈。2014年,南水北调中线工程通水,将逐步改善华北平原的用水结构,为地下水回灌和涵养提供了条件。地下水数值模型是地下水资源评价和管理的重要工具,在区域地下水流模型中对水源地、降落漏斗区域或者回灌区域进行加密,可提高局部重点区域的模拟精度。本文是在对基于MODFLOW的Share-node法和Ghost-node法局部加密技术原理的学习和对比的基础上,以滹沱河冲洪积扇区域地下水流模型为实例模型应用LGR-GN方法加密方法建立区域和勘查区耦合的地下水模型,对LGR-SN和LGR-GN实例应用效果进行对比。确定了以单程耦合和LGR-GN双向耦合结合的方式,以回灌影响范围建立其过渡承接作用的中模型,用中模型分别作为子模型和母模型与区域模型和场地模型耦合,建立区域和场地二级加密耦合模型。在地下水流模拟中,两种加密方法加密效果差别很小,LGR-SN在差值精度上有优势,LGR-GN在源汇项处理尤其是面状补排项处理上占优势;网格加密区开采井处理到每个网格对模拟结果和运行时间影响不大,只是占用空间明显较大。本文确定的二级加密方法中以回灌影响范围确定过渡模型的范围和以给定水位的方式进行过渡模型边界的处理,经验证,过渡中模型边界不受场地加密影响,能够控制回灌对过渡模型边界的影响;区域模型耦合的场地模型模拟得到的流场变幅更贴近实际,水丘更明显,在实际操作中因场地模型面积小,条件简单,增加的工作内容不多,这种通过二级加密实现大比例加密的方法可以为以后多区域局部加密使用;区域和场地耦合模型模拟场地回灌7年最多高出无回灌条件的水位1.04m,至场地边界处,影响不到0.5m,至中模型边界,影响不到0.1m;局部的井灌对区域流场影响很小,需在区域内大量布置回灌设施进行长期地下水回灌工作,以实现区域地下水位的恢复和地下水超采趋势的缓解。
[Abstract]:More than 70% of the water used in North China Plain depends on groundwater, which is insufficient in recharge and seriously overexploited for a long time, resulting in a sharp decrease in the quantity of groundwater resources and frequent environmental geological disasters such as land subsidence, which has become a bottleneck restricting sustainable development in 2014. The diversion of water in the middle route of South-to-North Water transfer Project will gradually improve the water use structure of North China Plain and provide conditions for groundwater recharge and conservation. Groundwater numerical model is an important tool for groundwater resources evaluation and management. In the regional groundwater flow model, the simulation accuracy of the local key area can be improved by infilling the water source, the landing funnel area or the recharge area. This paper is based on the study and comparison of the principle of Share-node method and Ghost-node method based on MODFLOW. Taking the groundwater flow model of Hutuo River alluvial fan area as an example, the LGR-GN method is used to establish the coupled groundwater model between the area and the exploration area. The results of the application of LGR-SN and LGR-GN are compared. In this paper, the middle model of transition and undertaking is established by combining one-way coupling and LGR-GN bidirectional coupling, and the middle model is used as sub-model and parent model to couple with regional model and site model respectively. The coupling model of area and site two-level encryption is established. In groundwater flow simulation, there is a small difference in encryption effect between the two encryption methods. LGR-SN has advantages in difference accuracy. LGR-GN has advantages in source and sink item processing, especially in surface filling and drainage treatment. The processing of well in the grid infill area has little effect on the simulation result and running time, but the space is obviously larger. In the two-stage encryption method determined in this paper, the range of transition model is determined by the influence range of recharge and the boundary of transition model is treated by the way of given water level. It is verified that the model boundary is not affected by site encryption in transition. It can control the influence of recharge on the boundary of the transition model, the flow field amplitude obtained by the field model coupled with the regional model is more close to the reality, the water dome is more obvious, and the condition is simple because of the small area of the site model in practical operation. The increase of work content is not much, this method can be used for multi-area local encryption through two-level encryption to achieve a large proportion of encryption; The coupling model of region and site simulates that the water level of recharge is 1.04m higher than the water level without recharge condition for 7 years, but it affects less than 0.5m to the boundary of the site, and less than 0.1m to the boundary of the middle model, and the local well irrigation has little effect on the regional flow field. It is necessary to arrange a large number of recharge facilities in the area for long-term groundwater recharge in order to restore the regional groundwater level and alleviate the trend of groundwater overexploitation.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641
本文编号：2142946
[Abstract]:More than 70% of the water used in North China Plain depends on groundwater, which is insufficient in recharge and seriously overexploited for a long time, resulting in a sharp decrease in the quantity of groundwater resources and frequent environmental geological disasters such as land subsidence, which has become a bottleneck restricting sustainable development in 2014. The diversion of water in the middle route of South-to-North Water transfer Project will gradually improve the water use structure of North China Plain and provide conditions for groundwater recharge and conservation. Groundwater numerical model is an important tool for groundwater resources evaluation and management. In the regional groundwater flow model, the simulation accuracy of the local key area can be improved by infilling the water source, the landing funnel area or the recharge area. This paper is based on the study and comparison of the principle of Share-node method and Ghost-node method based on MODFLOW. Taking the groundwater flow model of Hutuo River alluvial fan area as an example, the LGR-GN method is used to establish the coupled groundwater model between the area and the exploration area. The results of the application of LGR-SN and LGR-GN are compared. In this paper, the middle model of transition and undertaking is established by combining one-way coupling and LGR-GN bidirectional coupling, and the middle model is used as sub-model and parent model to couple with regional model and site model respectively. The coupling model of area and site two-level encryption is established. In groundwater flow simulation, there is a small difference in encryption effect between the two encryption methods. LGR-SN has advantages in difference accuracy. LGR-GN has advantages in source and sink item processing, especially in surface filling and drainage treatment. The processing of well in the grid infill area has little effect on the simulation result and running time, but the space is obviously larger. In the two-stage encryption method determined in this paper, the range of transition model is determined by the influence range of recharge and the boundary of transition model is treated by the way of given water level. It is verified that the model boundary is not affected by site encryption in transition. It can control the influence of recharge on the boundary of the transition model, the flow field amplitude obtained by the field model coupled with the regional model is more close to the reality, the water dome is more obvious, and the condition is simple because of the small area of the site model in practical operation. The increase of work content is not much, this method can be used for multi-area local encryption through two-level encryption to achieve a large proportion of encryption; The coupling model of region and site simulates that the water level of recharge is 1.04m higher than the water level without recharge condition for 7 years, but it affects less than 0.5m to the boundary of the site, and less than 0.1m to the boundary of the middle model, and the local well irrigation has little effect on the regional flow field. It is necessary to arrange a large number of recharge facilities in the area for long-term groundwater recharge in order to restore the regional groundwater level and alleviate the trend of groundwater overexploitation.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641
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