【作者】 张恒；

【导师】 李晓； 许模；

【作者基本信息】 成都理工大学 ， 环境工程， 2005， 硕士

【摘要】 水电工程是人类进行的大型工程活动,对环境可能产生较大的影响。本论文以乌东德电站为例,通过建站前地下水及地表水环境特征的研究,分析建站后地下水渗流场和水质可能产生的变化,以及对环境可能产生的影响。论文运用地质-水文地质调查、水文地球化学方法、稳定同位素分析等多种方法,系统分析了研究区天然水化学特征、氢氧稳定同位素组成特征,水体循环系统特征。在此基础上运用Visual MODFLOW软件,进行了建站前后地下水三维渗流场数值模拟分析。 通过各种方法结合综合分析,得出主要成果和认识如下: （1） 研究区位于开阔的方家山向斜南西翼,地层北东向缓倾倾角5—20°。主要出露地层震旦Zbd¹白云岩为裂隙、溶隙含水的强含水层,二叠系P₁石英砾岩为相对隔水层;T₃-K砂泥岩互层为构造裂隙和风化裂隙含水的弱含水层。 （2） 同位素分析查明研究区地表水及地下水补给源为大气降水,地层富水性差异形成研究区多层相互独立的地下水系统,上层为就近降水补给,下层为高海拔降水补给,地下水流向金沙江。 （3） 研究区地表水矿化度总体低于地下水,地表水矿化度最高含量为443.40mg/L,水化学类型以HCO₃—Ca·Mg、HCO₃·SO₄—Ca·Mg型水为主。地下水矿化度含量283.9—845.5 mg/L,水化学类型有HCO₃—Ca·Mg、HCO₃·SO₄—Ca·Mg、SO₄·HCO₃—Ca·Mg,矿化度的高低主要受Ca²⁺、Mg²⁺、SO₄^2-离子含量影响。 （4） 运用Visual MODFLOW软件对研究区地下水渗流场进行三维数值模拟,分析体现出河谷两岸及沟谷间形成的分水岭,峡谷内地势落差大水力梯度递增带,建站后水位场发生变化,坝肩帷幕位置水力梯度突增,展现了大坝截流阻水的功能,使原来不含水地层由于地下水壅高而含水。 （5） 研究区局部地段水流切割含硫铁矿地层,使SO₄^2-离子含量和矿化度升高,并具有强酸性,该类水对坝基建筑混凝土有强结晶类腐蚀作用;电站建设将对研究区环境造成影响,改变原有乌东德峡谷河流形态,增大气候的湿度,使原有单一贫乏的生物链变得多态化,一定程度将带动电站地区的经济发展。更多还原

【Abstract】 Hydroelectric projects are large-scale man-made engineering activities, which may produce larger influences. The paper, taking Wudongde hydroelectric station for example, analyzes groundwater infiltration flow field, possible changes of water quality and potential influences on environment after building the station through the investigation of groundwater and surface water environment character before building the station. Many methods are used such as geology-hydrogeology survey, hydrogeochemical technique, stable isotope analysis and so on. The paper uses these methods to investigate the characters of natural Hydrochemistry, Oxygen -Hydrogen stable isotope composition and water circulating systems. On the basis of these, do three-dimensional groundwater infiltration flow field numerical model analysis before and after building the station by using the software of Visual MODFLOW.Through each method , combining with synthetic analysis, it can include some main achievements as following:(1) The study area is located on the southwest alar of Fangjiashan syncline. The low-angle dip of stratum is 5—20° . The main outcrop stratum (dolomite rock of Zbd1) is crevice and solution crevice strong aquifer. The quartz conglomerate of P1 is relative water separation stratum. The interbed of sandstone and mudstone (T3-K) is structural and weathering crevice aquitard.(2) According to isotope analysis, the recharge source of surface water and groundwater is precipitate water. The multiplayer mutually independent groundwater systems are caused by the difference of water-bearing statum. The upper aquifer recharge is precipitate water. The under aquifer is recharged by high altitude precipitate water. The groundwater flows into Jingshajiang.(3) the mineralizations of study area are generally low than surface water. The highest mineralization is 443.40mg/L. The main Hydrochemical types are HCO3—Ca . Mg、HCO3.SO4 —Ca . Mg. The groundwater mineralizations are range from 283.9 to 845.5 mg/L and the type of hydrochemistry includes HCO3—Ca . Mg 、 HCO3 . SO4—Ca . Mg、 SO4 . HCO3—Ca . Mg. The quantity of mineralization is influenced by the ion content of Ca2+、 Mg2+、 SO42-.(4) The software of Visual MODFLOW is used to carry through three-dimensional numerical model for groundwater infiltration flow field, which lays out the watershed between two sides of river valley and river valley, increasing zones of hydraulic gradient with high terrain fall and changes of water level field after building the station . The sudden increasing of hydraulic gradient in the location of dam abutment shows the cut-off function of dam, which makes water-free strata contain water caused by the raise of groundwater.(5) Water flow of local sections in the study area cuts the strata with pyrites, which increases SO42- ion content and mineralization and makes the water with strong acid. This kind of water has strongly crystal corrosion effect on building concretes of base foundation. The hydroelectric construction will influence the environment of study area, change river state of original Wudongde canyon, raise the humidity of climate and make originally single and lean biologic chain become polymorphism, which will bring the economic development of hydroelectric area to the extent.更多还原