延安市新区造地工程地下水流数值模拟研究

发布时间：2018-11-26 17:52

【摘要】：为缓解延安老城的城市用地紧张局面,将进行城市造地工程建设新区。然而,城市造地工程活动会对黄土丘陵沟壑区地下水流场产生影响,进而改变当地工程地质环境：如水位过高地基土壤盐渍化,破坏建筑基础；水位忽高忽低容易引起黄土湿陷等。利用数值模拟技术研究造地工程影响下地下水流时空分布及其演化机制,对后续工程建设及水资源开发利用具有十分重要的意义,同时为黄土丘陵沟壑型城市造地工程中的地质灾害与防治提供借鉴。本文在分析研究区地质和水文地质条件的基础上,基于Feflow软件和ArcGIS技术建立了研究区造地工程地下水流数值模型,城市造地工程数值模型包括地表不硬化沟底不设盲沟(工况A)、地表硬化沟底不设盲沟(工况B)和地表硬化沟底设盲沟(工况C)。对新区造地工程地下水流数值模型校正后,分别进行了三种工况下短长期地下水流数值模拟,预测了各工况在短期和长期地下水位变化、埋深分布以及盲沟排水效果。结果表明：新地貌对地下水位变化起支配的作用,导水盲沟则发挥辅助作用。硬化措施使地表水入渗补给相对困难,导水盲沟的铺设显著地改善了沟底地层的导水性,硬化措施和导水盲沟可使地下水水位降低约20m左右；在各工况下对比分析历年水力梯度变化差值以及主沟、次沟的上游与下游水位差增大比的大小可知,次盲沟比主盲沟的疏排效率更高,但在50年模拟末期,主盲沟水力梯度大于次盲沟水力梯度,预测未来主盲沟将承担主要疏排工作。
[Abstract]:In order to alleviate the tense situation of urban land use in Yenan Old City, urban land construction project will be carried out to build a new area. However, the urban land engineering activities will affect the groundwater flow field in the loess hilly and gully region, and then change the local engineering geological environment: such as the soil salinization of the high water level and the destruction of the building foundation; The fluctuation of water level can easily lead to loess collapsing and so on. Using numerical simulation technology to study the spatial and temporal distribution of groundwater flow and its evolution mechanism under the influence of land reclamation projects is of great significance for the subsequent engineering construction and water resources development and utilization. At the same time, it provides reference for geological hazard and prevention in loess hilly and gully urban land construction. Based on the analysis of geological and hydrogeological conditions in the study area, a numerical model of groundwater flow in the study area is established based on Feflow software and ArcGIS technology. The numerical model of urban land engineering includes no blind ditch (A),) and no blind ditch (working condition C). After the correction of the numerical model of groundwater flow in the new area, the short-term and long-term groundwater flow numerical simulation was carried out under three conditions, and the variation of groundwater level, the distribution of buried depth and the drainage effect of blind ditch were predicted in the short and long term. The results show that the new geomorphology dominates the change of groundwater level, while the blind channel plays an auxiliary role. The surface water infiltration and recharge is relatively difficult by hardening measures, and the water conductivity of the bottom stratum is significantly improved by the laying of the water conduction blind ditch, and the groundwater level can be reduced about 20 m by the hardening measures and the water conduction blind ditch. The difference of hydraulic gradient and the increase ratio of water level difference between upstream and downstream of secondary ditch are analyzed in different working conditions. It can be seen that the drainage efficiency of secondary blind ditch is higher than that of main blind ditch, but at the end of 50 years, the drainage efficiency of secondary channel is higher than that of main channel, but at the end of 50 years, The hydraulic gradient of the main blind ditch is larger than that of the secondary blind ditch, and it is predicted that the main blind ditch will undertake the main drainage work in the future.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641.2

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