呼和浩特盆地地下水年龄结构与补给流动模式研究

发布时间：2018-06-20 21:08

本文选题：地下水年龄 + 包气带　；参考：《中国地质科学院》2016年博士论文

【摘要】：呼和浩特盆地作为一个以开采地下水为主要水源的地区,在经历了近30年的高强度开采后,地下水环境受到极大的破坏,诸如地下水降落漏斗的形成,承压水自流区范围的缩小以及地下水污染等,地下水资源的可持续利用面临着严峻的挑战。而地下水补给与流动规律的研究作为识别地下水循环过程和分析地下水形成分布规律的基础,对保障一个区域地下水资源的可持续利用具有重要的理论和现实意义。本研究分别从包气带和含水层入手,提取其中所包含的水化学和同位素信息,在综合利用多种测年方法对比构建地下水年龄结构的基础上,结合不同水体中的氢氧稳定同位素及水化学特征追踪地下水的补给来源,分析地下水的补给规律,刻画地下水的流动模式,并结合传统的水文地质学方法对含水层之间的水力联系及可更新性等进行评估。研究主要侧重在三个方面:(1)地下水年龄结构的构建;(2)地下水补给流动模式的刻画;(3)含水层之间的水力联系的识别。通过研究取得的进展主要有:(1)估算了盆地地下水的年龄。在年轻地下水测年方面,引入年轻地下水85Kr测年方法,并与3H-3He法、CFCs方法、3H方法得出的年龄结果对比分析,筛选出合理的潜水年龄的结果,改变了以往仅根据水文地质条件消除年龄多解性的问题,并对不同方法造成年龄结果差异存在的原因给出了解释,减少了单一方法存在的误差;在年老地下水测年方面,联合使用传统化学校正方法和netpath方法对承压水的14C的年龄进行校正,对各种方法得出了结果进行了对比分析,获得了更为合理的承压水14C年龄,提升了校正的精度,在此基础上,构建了地下水的年龄结构。(2)识别了盆地地下水的补给来源及补给机制,主要通过氢氧稳定同位素和地下水年龄的分布特征获得。分析的结果显示该区地下水的补给来源主要有山区降水、当地降水、地表水、灌溉回归水及部分黄河水等,并且在不同的地区略有差异。在东部地区主要是当地降水、地表水和灌溉回归,在北部地区主要是山区降水和地表水,在中部地区主要是降水和灌溉回归。补给机制主要以侧向径流为主,局部地区存在垂向补给和黄河水补给。(3)估算了地下水的天然补给速率和综合补给速率。地下水的天然补给速率主要通过包气带人工氚示踪方法和氯质量平衡方法对比分析获得,地下水的综合补给速率主要通过地下水的年龄随流动路径的变化而获得。在综合分析地下水的天然补给速率和综合补给速率的基础上,区分出不同补给方式及所占的贡献份额,为地下水的合理开采提供了依据。(4)证实了在盆地局部地区地下水降落漏斗附近及淤泥层边界附近存在潜水越流补给承压水的现象,同时发现盆地地下水流系统中同时存在区域地下水流系统和局部地下水流系统。区域地下水流系统大致以湖相沉积为主的冲湖积平原的边界为界,分为东部以河流相沉积为主的冲洪积、冲湖积平原区域地下水流系统和西部以湖相沉积为主的冲湖积平原两个区域地下水流动系统。局部水流系统主要出现在地下水开采漏斗区和越流发生区。(5)评价了呼和浩特盆地地下水系统的可更新性和防污性,为地下水的合理开采提供了理论依据。结果显示在呼和浩特盆地冲洪积平原和冲湖积平原的大部分区域含水层的防污性中等。大青山和蛮汉山前的大部分区域(呼和浩特北部毫沁营镇——巴彦镇一带区域除外)和黑城乡附近的区域含水层的防污性低。
[Abstract]:The Hohhot basin, as a region with the exploitation of groundwater as the main source of water, has been greatly destroyed after nearly 30 years of high intensity mining, such as the formation of the ground water funnel, the narrowing of the scope of the self flow area of the confined water and the pollution of the groundwater, and the sustainable utilization of groundwater resources is facing severe problems. The study of groundwater recharge and flow law is the basis for identifying the process of groundwater circulation and analyzing the distribution law of groundwater. It is of great theoretical and practical significance to ensure the sustainable utilization of groundwater resources in a region. This study extracts hydrochemistry from the air and aquifers respectively. And isotopic information, on the basis of using a variety of dating methods to compare the construction of groundwater age structure, combined with the hydrogen and oxygen stable isotopes and hydrochemical characteristics in different water bodies to trace the source of groundwater recharge, analyze the regularities of groundwater recharge, depict the flow pattern of groundwater, and combine the traditional hydrogeological method to contain the groundwater. The hydraulic connections and renewability between water layers are evaluated. The study mainly focuses on three aspects: (1) construction of groundwater age structure; (2) characterization of groundwater recharge flow patterns; (3) identification of hydraulic connections between aquifers. The progress achieved through research is mainly: (1) estimating the age of groundwater in the basin. In the year of water survey, the young groundwater 85Kr dating method was introduced, and the age results obtained by 3H-3He, CFCs and 3H methods were compared and analyzed. The results of reasonable diving age were screened out, which changed the problem of eliminating age solution by only hydrogeological conditions, and gave the reasons for the difference of the age results of different methods. The error of the single method is reduced. In the year of the old groundwater survey, the traditional chemical correction method and the netpath method are used to correct the age of the 14C in the confined water, and the results are compared and analyzed. The more reasonable 14C age of the pressure water is obtained, and the accuracy of the correction is improved. On the basis of this, the age structure of groundwater is constructed. (2) the source and recharge mechanism of groundwater in the basin is identified, mainly through the distribution characteristics of the hydrogen and oxygen stable isotopes and the distribution of groundwater age. The results show that the source of groundwater recharge mainly includes mountain precipitation, local precipitation, surface water, irrigation and regression water and some the Yellow River. Water and other areas are slightly different in different regions. In the eastern region, mainly local precipitation, surface water and irrigation regression, mainly in the northern region of mountain rainfall and surface water, in the central region mainly precipitation and irrigation regression. The main supply mechanism is mainly lateral runoff, the local area has vertical recharge and the Yellow River water supply. (3) estimated (3) The natural recharge rate and the comprehensive recharge rate of groundwater are obtained. The natural recharge rate of groundwater is obtained by the comparison and analysis of the artificial tritium tracer method and the chlorine mass balance method. The groundwater recharge rate is mainly obtained by the age of groundwater with the change of the flow path. On the basis of the recharge rate and the comprehensive recharge rate, different supply modes and contribution share are distinguished, which provide the basis for rational exploitation of groundwater. (4) it is proved that there is a phenomenon of submersible overflow of water in the vicinity of the groundwater descending funnel and the boundary of the silt layer in the part of the basin, and the groundwater flow in the basin is found at the same time. The regional groundwater flow system and the local groundwater system exist at the same time. The regional groundwater flow system is roughly bounded by the lacustrine sedimentary plain of the lake deposit, which is divided into the flood alluvium mainly in the eastern part of the river facies, the groundwater flow system in the lacustrine plain area and the lacustrine sedimentary plain in the western region, mainly by the lake facies. Two A regional groundwater flow system. The local flow system mainly occurs in the funnel area and the overflowing area of the groundwater. (5) the groundwater system in Hohhot basin is evaluated for its renewability and antifouling, which provides a theoretical basis for the rational exploitation of groundwater. Medium most of the regional aquifer vulnerability. Most areas of Mount Daqing and piedmont man Han (except northern Hohhot haoqinying town - the town of Bayan area) and the pollution of black urban and rural areas near the regional aquifer is low.
【学位授予单位】：中国地质科学院
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P641.6

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