大连市周水子地区海水入侵问题研究

【作者】 丁玲；

【导师】 张树深；

【作者基本信息】 大连理工大学 ， 环境工程， 2004， 硕士

【摘要】 海水入侵是指由于陆地淡水水位下降而引起的海水直接侵染地下淡水层的一种环境地质恶化现象，它是人类在沿海地区的社会活动导致的一种人为自然灾害。海水入侵是由自然和社会环境中诸多因素长期共同作用的结果，其中最直接的原因是地下水位的持续下降和降水的严重不足。近年来，我国沿海城市由于过量开采地下水，大多不同程度的出现海水入侵问题。大连市是海水入侵比较严重的城市，并且已经影响到了国计民生，海水入侵是该市地下水开发利用出现的主要问题。 本论文主要对大连市周水子区域海水入侵态势进行了模拟研究，应用美国地质调查局公开发表的SUTRA地下水质模型进行了模拟计算，以功能强大的科技绘图软件TECPLOT对其模拟结果进行后处理分析。并针对国内外控制海水入侵灾害的技术和方法，结合我国海水入侵实际情况，探讨了建立淡水帷幕、加设防渗墙等防治措施的对策。 论文第一章文献综述部分首先论述了海水入侵给国际上的许多国家特别是中国带来的灾害，其次分析了本文的选题背景和意义，然后在此基础上对海水入侵的概况、机制、海水入侵的基本理论、国内外海水入侵问题研究方法及现状进行了概括，最后提出了本研究课题的内容及方法。 第二章是本论文的基础部分，论述了本论文研究区域的水文地质条件。第三章介绍了SUTRA数值模型基本原理和TECPLOT图形后处理软件。 第四章是将模型应用于大连市周水子区域，根据水文院提供的相关地质资料，分析地质概况，建立概念模型，模拟了三年内海水入侵内陆的态势，并与观测数据进行了比较。计算结果表明，该模型方法可靠，预测合理，可以对地下水资源的利用与开发进行相应的工程规划。在此基础上分析了入侵距离随降雨量的变化趋势、过渡带宽度以及咸淡水界面的变化规律，为后续的海水入侵防治措施提供了一定的参考依据。 第五章假设了几种回灌—开采方案，定量分析比较了250mg/L、5g/L、10g/L浓度线的运移变化规律，来说明淡水帷幕的作用。在淡水帷幕的形成过程中，回灌流量是主要的影响因素，回灌流量越大，帷幕作用越显著。然后拟定算例说明回灌位置的优化选择以及咸淡水界面的变动情况。第六章针对防渗墙对海水入侵的屏障作用进行了分析论证。第七章扼要的总结了本论文所取得的研究成果，并提出今后进一步研究的方向。更多还原

【Abstract】 Seawater intruding into groundwater layer caused by the drop of freshwater level of earth is a worsening phenomenon of environmental geology named seawater intrusion. It is an artificial disaster of nature induced by human’s social activities in coastal cities. The long-term co-operation of many environmental factors of nature and society has resulted in seawater intrusion, and the most direct causes are sustained lowering of groundwater level and severe deficiency of rainfall. Recently, most of coastal cities in China have been up against seawater intrusion problem to some extend. This problem in the city of Dalian is relatively serious, and even affects the national economy and the people’s livelihood. It has become the leading question for the development and utilization of groundwater.The situation of seawater intrusion in the district of ZhouShuizi Dalian is simulated applying SUTRA in this paper. The software TECPLOT which shows a powerful function in technological drawing, is used to do post processing analysis towards the simulation results. About the technique and method to controlling seawater intrusion disasters inland and abroad, some control measures such as setting up a freshwater barrier and adding a cutoff wall are discussed, combining with the specific fact in China.In chapter 1, disasters brought by seawater intrusion to many countries, especially China, are discussed at first, the background and significance of project selection are analyzed, too. Then, on the basis of this, general conditions, mechanism, basic theory of seawater intrution, research methods and present conditions on seawater intrusion inland and abroad are summarized. Finally, the contents and approach for this research are put forward.Chapter 2 is the basis of this paper and hydrogeological conditions of the research region are revealed here. Fundamental principle of SUTRA numerical model and TECPLOT graphical post processing software are introduced in Chapter 3.The model is applied to the district between Dalian Bay and ZhouShuizi in Chapter 4. Based on relevant geological data by Bureau of Hydrology, general geological condition of the research region is analyzed, and a conceptual model is established. The situation of seawater intrusion into inland area during three years is simulated and compared with the observated data. Results show that the model is reliable, and the prediction is reasonable. So it can be used to make project planning for utilization and exploitation of groundwater resources. In addition, the variation tendency of intrusion distance along with precipitation amount and the variation law of the width of transition zone and seawater-freshwater interface are analyzed, providing some references for establishing control measures subsequently.In chapter 5, several sorts of back pour-extracting schemes are supposed and the variation law of 250mg/L,5g/L,10g/L concentration contours are analysed quantificationally to illustrate the function of freshwater barrier. During the forming process of freshwater barrier, back pour amount is the key factor. The higher the amount is, the more remarkable the function is.Then, optimum selection of the back pour plots and the variation situation of seawater-freshwater interface are explained by designing projects. Theshielding effect of cutoff wall to seawater intrution is analysed and demonstrated in Chapter 6. Finally, conclusions and research tendency are summarized briefly.更多还原