济南岩溶水系统多级次循环模式分析及识别方法研究

发布时间：2018-05-08 08:26

本文选题：地下水流系统 + 排泄区　；参考：《中国地质大学》2016年博士论文

【摘要】：深入认识地下水循环规律,是合理开发利用地下水资源的基础。地下水流系统理论揭示了地下水的系统性和结构性,是研究地下水循环和演化的有力工具。本文以地下水流系统理论为指导,以济南岩溶水系统为研究对象,将济南北部地热水与南部岩溶冷水作为整体进行研究,基于研究区水文地质条件,综合应用多种手段,来有效识别不同级次的地下水流系统,分析地下水循环模式。将排泄区作为地下水流系统的“指纹”,通过提取和融合排泄区的一系列水文地质信息(地质条件、水位动态、水化学、同位素等),来推测地下水循环模式：第四系浅层地下水属于局部地下水流系统,以高NO3-浓度、富集氢氧重同位素为特征,受当地大气降水直接入渗补给,部分地段受岩溶水顶托补给；岩溶冷水来自中间地下水流系统,以均一的水化学类型(HCO3-Ca(Mg)型)、低NO3-浓度和相对偏负的氢氧同位素为特征,受到来自山前灰岩裸露区的侧向径流补给,通过人工开采和泉群排泄；岩溶热水由区域地下水流系统经深循环形成,以高Cl-、TDS浓度,贫氢氧重同位素和长滞留时间为特征,来源于晚更新世时期(26.68-13.44 kaBP)温度较低的大气降水入渗补给,补给区位于泰山北麓高海拔地区。从地下水流系统的时间属性出发,利用滞留时间分布的不连续特征来识别不同级次的地下水流系统。考虑地形起伏的复杂性,引入济南地区真实数字高程到三维地下水流系统模型中,以地下水滞留时间概率密度函数中的拐点作为临界滞留时间来划分盆地地下水滞留时间场,进而识别不同级次的地下水流系统。分别设置不同的影响因子(入渗补给强度、介质各向异性、热运移),根据模拟得到的盆地地下水滞留时间分布变化,以及不同级次水流系统的补给量和体积变化来定量分析不同因素对三维地下水流系统分布特征和循环模式的影响。选取典型剖面建立地下水流-年龄耦合数值模拟模型,模拟结果与概念模型分析一致：泰山北麓至齐广断裂发育多级次地下水流系统,局部、中间和区域流动系统嵌套分布,地形控制了不同级次水流系统的发育规模,含水层岩性变化是影响水流系统模式的重要因素。地下水年龄分布与水流系统密切相关,地下水年龄沿流动路径整体呈变老趋势,内部驻点附近地下水年龄存在突然增大的界面,是不同级次水流系统分界的重要标志。本文的研究成果不仅加深了对济南岩溶水系统地下水循环规律的认识,促进当地地下水资源的合理开发利用,也为地下水流系统理论的实践应用提供了参考。
[Abstract]:It is the foundation of rational exploitation and utilization of groundwater resources to deeply understand the regularity of groundwater circulation. The theory of groundwater flow system reveals the system and structure of groundwater and is a powerful tool to study the circulation and evolution of groundwater. Guided by the theory of groundwater flow system and taking the karst water system of Jinan as the research object, this paper takes the geothermal water in the north of Jinan and the karst cold water in the south of Jinan as a whole. Based on the hydrogeological conditions of the study area, a variety of methods are comprehensively applied. To identify the groundwater flow system and analyze the groundwater circulation model. The discharge area is used as the "fingerprint" of the groundwater flow system by extracting and integrating a series of hydrogeological information (geological conditions, water level dynamics, hydrochemistry) of the discharge area, Isotopes, etc., to infer the circulation model of groundwater: Quaternary shallow groundwater belongs to local groundwater flow system, characterized by high no _ 3- concentration, enrichment of hydrogen and oxygen heavy isotopes, and is recharged directly by local atmospheric precipitation. The karst cold water comes from the intermediate groundwater flow system and is characterized by the homogeneous hydrochemical type (HCO3-CaOMg) type, low NO3- concentration and relatively negative hydrogen and oxygen isotopes. By lateral runoff recharge from exposed areas of limestone in front of mountains, karst hot water is formed by deep circulation of regional groundwater flow system, characterized by high concentration of Cl-tds, heavy isotope of hydrogen and oxygen, and long residence time. The recharge of precipitation from the lower temperature during the late Pleistocene is 26.68-13.44 kaBP.The recharge area is located in the high altitude area of the northern foot of Mount Tai. Based on the time attribute of groundwater flow system, the discontinuous character of residence time distribution is used to identify the groundwater flow system of different order. Considering the complexity of terrain fluctuation, the real digital elevation of Jinan area is introduced into the three-dimensional groundwater flow system model, and the inflexion of the probability density function of groundwater retention time is taken as the critical retention time to divide the groundwater retention time field in the basin. Then the groundwater flow system of different order is identified. Different influencing factors (infiltration recharge intensity, medium anisotropy, thermal migration) were set up, and the groundwater retention time distribution in the basin was obtained by simulation. The effects of different factors on the distribution characteristics and circulation model of three dimensional groundwater flow system are quantitatively analyzed. The numerical simulation model of groundwater flow and age coupling is established by selecting typical sections. The simulation results are consistent with the conceptual model analysis: the multi-stage subgroundwater flow system is developed from the northern foot of Mount Tai to the Qi-guang fault, and the local, intermediate and regional flow systems are nested. The topography controls the development scale of different order water flow system, and the lithologic change of aquifer is an important factor influencing the flow system model. The age distribution of groundwater is closely related to the flow system, the groundwater age along the flow path shows a trend of aging, and there is a sudden increase in the groundwater age near the internal stationary point, which is an important indicator of the boundary of different order flow systems. The research results of this paper not only deepen the understanding of groundwater circulation law in Jinan karst water system, promote the rational development and utilization of local groundwater resources, but also provide a reference for the practical application of groundwater flow system theory.
【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P641.134

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