上海崇明岛南岸某剖面长江水—地下水相互作用定量化研究

发布时间：2018-06-27 21:18

本文选题：泥质潮滩 + 海底地下水排泄　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：随着海岸带经济的高速发展,滨海含水层中受到潮波影响的地下水流的研究已经成为了水文地质和生态环境领域的一个热点、重要课题。在过去的三十年里,滨海含水层水动力学的数值模拟工作得到了快速发展。本文选取了崇明岛南岸潮间带地下水含水层为研究对象,在潮滩上选取了一个竖直剖面,使用自动传感器对研究区潮滩地下水和潮汐的压力水头、温度和盐度进行自动观测。在滨海含水层中,随海潮的周期性变化的地下水位包含了重要的水文地质信息。本文通过收集、分析崇明岛水文地质、海潮、海洋水文和气象等资料,并使用二维有限单元法数值模拟软件MARUN,建立了中等尺度数值模型,从而对地下水水头进行了数值模拟。通过对研究区相关资料和地下水水位、温度、盐度等观测资料的分析可以得出:崇明岛长江南支水位受海潮波动的影响显著,表现为每天两个不同周期的不规则半日潮以及以15天为周期的大小潮。长江南支江水为淡水,且盐度低于内陆地下水盐度。崇明岛南岸潮滩含水层泥质含量多,其渗透性不好,江水水位波动在含水层中迅速衰减。本文分析了崇明岛南岸剖面的观测数据,并用MARUN进行了观测数据的数值拟合和模型参数的校正。基于野外观测数据和室内数值模拟,得出了以下结论:研究区剖面含水层的横、纵向渗透系数、储水率、孔隙度等几个主要的水文地质参数的估算值分别为8×10-7m s-1、4×10-7m s-1、10-5 m-1、0.4。在一个完整大小潮周期,研究区海岸处的SGD量为0.46 m3d-1m-1,内陆淡水纯补给量为0.08m3d-1m-1(即陆源淡水SGD)占SGD总量的17.4%。
[Abstract]:With the rapid development of coastal zone economy, the study of groundwater flow affected by tidal waves in coastal aquifer has become a hot and important topic in the field of hydrogeology and ecological environment. In the past 30 years, the numerical simulation of coastal aquifer hydrodynamics has been developed rapidly. In this paper, the groundwater aquifers in the intertidal zone along the south coast of Chongming Island are selected as the research objects, a vertical section is selected on the tidal flat, and the pressure head, temperature and salinity of the tidal flat groundwater and the tide in the study area are observed automatically by using the automatic sensor. In the coastal aquifer, the groundwater level, which changes periodically with the tide, contains important hydrogeological information. By collecting and analyzing the hydrogeological, tidal, marine hydrological and meteorological data of Chongming Island, a mesoscale numerical model has been established by using the two-dimensional finite element method software Marun to simulate the groundwater head. Based on the analysis of the relevant data and the observation data of groundwater level, temperature and salinity, it can be concluded that the water level in the south branch of the Yangtze River in Chongming Island is significantly affected by the fluctuation of the sea tide. The results show that there are two irregular semidiurnal tides with two different cycles each day and the large and small tides with a period of 15 days. The water in the south branch of the Yangtze River is fresh water, and the salinity is lower than that of inland groundwater. The muddy aquifer in the south coast of Chongming Island is rich in mud, and its permeability is not good, and the fluctuation of river water level decays rapidly in the aquifer. In this paper, the observed data of the south coast of Chongming Island are analyzed, and the numerical fitting of the observed data and the correction of the model parameters are carried out by using Marun. Based on field observation data and indoor numerical simulation, the following conclusions are drawn: the estimated values of several main hydrogeological parameters, such as horizontal, longitudinal permeability coefficient, water storage rate and porosity, are 8 脳 10 ~ (-7) m ~ (-1) ~ 4 脳 10 ~ (-7) m ~ (-1) -10 ~ (-5) m ~ (-1), respectively. In a complete tidal cycle, the amount of SGD at the coast of the study area is 0.46m3d-1m-1, and the net replenishment of inland freshwater is 17.4% of the total 0.08m3d-1m-1.
【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;P333

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