北京西山岩溶水系统的循环特征和可更新能力研究

发布时间：2018-06-19 20:53

本文选题：岩溶水循环 + 地下水年龄　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：西山岩溶水系统对北京平原区地表水和第四系孔隙水具有重要的调控功能。岩溶水具有水质优良、开发潜力大的特点,在当前地下水资源过度开采情况下,西山岩溶水系统功能存在减弱趋势。目前,关于西山岩溶水的循环特征有不同认识,但其可更新能力的研究相对较少。本文在野外调查的基础上,采用同位素法、水化学法和传统水文地质法,对西山岩溶水系统循环特征和可更新能力进行评价,为西山岩溶水的合理开发利用和科学管理提供依据。通过分析,得到以下认识:研究区第四系地下水在永丰屯地区具有TDS、pH及各离子浓度低,水化学类型简单的特征,石景山则与之相反。岩溶水Sr2+浓度沿着流向呈逐渐增大的变化趋势,水化学类型则由复杂变得单一;潭柘寺、军庄补给区岩溶水化学类型相对复杂,沿着岩溶水流向,在四季青、玉泉山地区水化学类型变为单一的HCO_3-Ca·Mg型水。研究区地表水、第四系地下水、岩溶地下水主要接受大气降水补给,且地表水、第四地下水受到蒸发作用影响强烈。潭柘寺地区岩溶水补给来源为大气降水,军庄岩溶水除了接受大气降水补给外,还受到大量河水渗漏补给,渗漏河水所占比例大于50%的岩溶水占统计岩溶水的68%,导致岩溶水中严重富集18O。利用同位素、水化学和水位地质资料揭示了西山岩溶水系统的的循环特征。岩溶地下水在潭柘寺、军庄地区接受补给后,分别沿着八宝山断裂、永定河断裂和白家疃断裂径流,最终在海淀背斜、四季青排泄。此外,不同补给区岩溶水的径流速度不同,由快至慢为:潭柘寺补给区径流速度永定河渗漏水径流速度军庄补给区(降水补给)径流速度。~3H、CFCs、~(14)C年龄表明,西山地区岩溶水是新水与老水的混合,年龄在3~2945年之间,但是整体上以小于30年为主,反映了西山岩溶水系统可更新能力强。山区岩溶水的可更新能力强于平原,从补给区到排泄区,地下水年龄增大,可更新能力逐渐减弱。潭柘寺补给区岩溶水的平均年龄小于军庄,地下水循环条件最好,可更新能力最强。
[Abstract]:Xishan karst water system plays an important role in regulating surface water and Quaternary pore water in Beijing plain. Karst water has the characteristics of excellent water quality and great potential for exploitation. Under the condition of over-exploitation of groundwater resources, the function of karst water system in Xishan is weakening. At present, there are different understandings about the circulation characteristics of karst water in Xishan, but there are few researches on its renewable ability. On the basis of field investigation, the circulation characteristics and renewable ability of karst water system in Xishan are evaluated by isotope method, hydrochemical method and traditional hydrogeological method. It provides the basis for rational development and utilization and scientific management of karst water in Xishan. The results show that the Quaternary groundwater in Yongfengtun area is characterized by low TDS pH, low ion concentration and simple hydrochemical types, whereas Shijingshan is the opposite. The concentration of Sr _ 2 in karst water increases gradually along the flow direction, and the hydrochemical type changes from complexity to singularity, while the chemical types of karst water in Tanzhe Temple, Junzhuang recharge area are relatively complex, flowing along the direction of karst water in Sijiqing, China. The hydrochemical type of Yuquanshan area is changed into a single HCO 3-Ca mg type water. Surface water, Quaternary groundwater, karst groundwater are mainly recharged by atmospheric precipitation, and surface water, the fourth groundwater is strongly affected by evaporation. The source of karst water recharge in Tanzhe Temple area is atmospheric precipitation. In addition to receiving precipitation recharge, Junzhuang karst water is also recharged by a large amount of river water leakage. More than 50% of karst water accounts for 68% of statistical karst water, which leads to serious enrichment of 18 O in karst water. The circulation characteristics of karst water system in Xishan are revealed by using isotopic, hydrochemical and water level geological data. After being recharged in Tanzhe Temple, Junzhuang area, karst groundwater flows along the Babaoshan fault, Yongding River fault and Baijiatuan fault respectively, and eventually drained in Haidian anticline and Sijiqing. In addition, the runoff velocity of karst water in different recharge areas is different, from fast to slow is: Yongding River leakage runoff speed, Junzhuang recharge area (precipitation recharge) runoff velocity. Karst water in Xishan area is a mixture of new water and old water, aged from 3 to 2945 years, but the whole karst water system is mainly less than 30 years, which reflects the strong renewable ability of karst water system in Xishan area. The renewable ability of karst water in mountainous area is stronger than that in plain, from recharge area to discharge area, groundwater age increases and the renewable ability weakens gradually. The average age of karst water in Tanzhe Temple recharge area is smaller than that in Junzhuang.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P641.134

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