沂沭河下游沿海平原地下水化学形成演化与水文地球化学模拟

发布时间：2018-06-07 14:49

  本文选题：沂沭河下游沿海平原 + 地下水　； 参考：《吉林大学》2017年硕士论文

【摘要】：地下淡水资源是我国沿海地区重要的供水水源?随着社会经济的快速发展,水资源需求量剧增,许多沿海地区由于过量开采地下水而引发了一系列环境地质问题?沂沭河下游沿海平原地处江苏沿海地区北部,发育有基岩裂隙水?孔隙潜水、第I?II?III?IV承压水,其中承压水为主要开采对象?多年的过量开采使II?III承压水位持续下降,形成了区域性水位降落漏斗,导致水质咸化,地面沉降等问题?为了合理的开发利用地下水,控制II、III承压地下淡水的咸化,需要明确研究区各层地下水的补径排条件,咸淡水的空间分布特征,识别出控制地下水水化学组分形成的主要水文地球化学作用?本文在充分分析沂沭河下游沿海平原地质?水文地质条件的基础上,综合分析水位?水化学及同位素数据,对研究区地下水补径排条件和水化学的形成演化机理进行了研究并应用水文地球化学模拟技术识别控制水化学行程演化的主要水文地球化学作用。主要取得了如下认识:1、裂隙水的径流方向受导水裂隙控制,TDS含量为400~600mg/L,多为HCO3-Na·Ca型水。裂隙水水化学的形成主要与基岩中长石矿物的溶解作用?2、在北部孤山丘陵区,潜水和I承压水呈放射状由山区向海径流。水力坡度达1.5‰,水循环交替较为强烈。潜水TDS含量在0.5g/L~2g/L之间,I承压水TDS含量略高于潜水。两者水化学类型多为HCO3-Na·Ca、Cl·HCO3-Na·Ca型。主要水岩作用为斜长石和黑云母的溶解作用,方解石的沉淀和阳离子交换作用,生成高岭石和伊利石?潜水还受蒸发浓缩作用和人类活动影响?3、在滨海平原区潜水和I承压水径流方向总体为由陆向海,I承压水在灌河口和滨海县一带向下越流补给II承压水。潜水受降水淡化,水质优于I承压水?I承压水TDS含量自西部400mg/L左右增加到滨海20g/L以上,水化学类型由内陆的HCO3-Ca型水逐渐演变至滨海的Cl-Na型水?控制滨海平原区潜水和I承压水水化学演化的作用主要为与海水的混合作用,广泛存在斜长石的溶解作用、方解石的沉淀作用和阳离子交替吸附作用?潜水受蒸发浓缩作用和人类活动影响。4、在滨海平原区,II承压水在陈家港?燕尾港一带接受了上覆I承压水越流补给,TDS含量高达20g/L以上,其他地区水质与III承压水相似,为淡水和微咸水。II?III承压水水化学类型空间分布类似,由内陆HCO3-Ca·Na型水至滨海的Cl·HCO3-Na·Ca型水。控制水化学演化的主要作用为斜长石?黑云母的溶解作用,方解石的沉淀作用,阳离子交换作用以及脱硫酸作用,伴随沉淀形成高岭石和伊利石?5、通过定量模拟识别出控制各水化学作用对地下水化学形成的贡献比例。以Na+浓度的变化为例,在非越流区,对深层承压水水化学形成贡献较大的作用为阳离子交替吸附或斜长石矿物溶解作用;在越流区贡献较大的作用为混合作用,其次为阳离子交替吸附作用或斜长石矿物的溶解作用。
[Abstract]:Groundwater resource is an important source of water supply in coastal areas of China. With the rapid development of social economy, the demand for water resources has increased dramatically. Many coastal areas have caused a series of environmental geological problems due to excessive exploitation of groundwater. The coastal plain of the lower reaches of the Yi-Shuhe River is located in the northern part of Jiangsu coastal area, where is there a bedrock fissure water? Pore diving, I?II?III?IV confined water, in which confined water is the main mining object? After years of excessive mining, the pressure level of II?III has continued to decline, forming a regional water level drop funnel, leading to water salinization, land subsidence and other problems. In order to develop and utilize groundwater reasonably and control the salinization of IIHIII confined groundwater, it is necessary to make clear the recharge and discharge conditions of groundwater in each layer of the study area and the spatial distribution characteristics of salty fresh water. Identify the main hydrogeochemical processes that control the formation of chemical components in groundwater? This paper fully analyzes the geology of the coastal plain in the lower reaches of the Yishu River. On the basis of hydrogeological conditions, comprehensive analysis of water level? The hydrochemistry and isotopic data were used to study the recharge and discharge conditions of groundwater and the formation and evolution mechanism of hydrochemistry in the study area. The hydrogeochemical simulation technique was applied to identify the main hydrogeochemical effects controlling the evolution of hydrochemical stroke. The main results are as follows: (1) the runoff direction of fissure water is controlled by water conductivity fissures, TDs content is 400 ~ 600mg / L, mostly HCO3-Na Ca type water. The formation of fissure water chemistry is mainly related to the dissolution of feldspar minerals in the bedrock. In the northern Gushan hilly area, the phreatic and I confined water flow radially from the mountains to the sea. The hydraulic slope reaches 1.5 鈥，

本文编号：1991565