【作者】 韩冬梅；

【导师】 靳孟贵； 梁杏；

【作者基本信息】 中国地质大学 ， 水文学及水资源， 2007， 博士

【摘要】 地下水系统的复杂性、隐蔽性给全面认识地下水系统特征带来困难。长期以来，人们试图用多种手段来认识地下水系统，也只能够获取地下水系统的部分信息。地下水是环境变化的受体和信息载体。基于地下水系统理论，提取、融合孤立零散的信息，可以降低不确定性，帮助我们正确认识地下水系统的本来面目。本文以忻州盆地第四系孔隙地下水系统为例，用多种技术手段和常规水文地质分析相结合，定量提取和融合零散信息，以综合的、系统的观点研究地下水流动系统。忻州盆地为山西省境内汾河地堑的最北部的新生代断陷盆地，地处干旱半干旱地区，地下水是其最重要的供水水源。上世纪80年代以来，随着社会经济的快速发展，人口的增长，水资源需求剧增，强烈的工农业活动和采矿改变着地下水天然赋存环境和区域水循环条件。盆地第四系地下水水位不断下降，地下水水质不断恶化，可利用地下水资源日趋减少，引发了一系列相关的水资源—环境问题，严重影响了城市工农业的发展。由于水资源管理方法不当，缺乏环境保护意识，水资源的开发利用与生产实践之间的矛盾日益突出。因此，有必要对人为活动和天然条件相互作用的地下水环境演化进行系统研究。以往忻州盆地的调查研究多停留在对盆地地下水系统定性的描述，主要使用传统水文地质分析方法进行地下水系统描述分析，对系统的级次划分还有着不同认识。从系统分析的角度重新认识忻州盆地地下水流动系统，有助于正确认识三维空间的水化学场和正确解释区域水化学特征所呈现的复杂现象，对于深入揭示相关地下水环境问题的根源、推动地下水流动理论的发展有着积极意义。此外，对明确地下水资源的时空演变和水循环演化规律，水资源开发利用规划方案论证、决策以及水资源的可持续利用具有现实意义。本次研究以系统理论为指导，将整个忻州盆地第四系孔隙地下水作为研究对象进行系统分析；利用多种技术手段提取忻州盆地第四系孔隙含水系统的介质组成及其结构、边界条件、补给径流排泄与动态均衡等信息，构建地下水流模型；系统分析了盆地地下水渗流场、水化学场（包括水化学组分和同位素组成）的定性或半定量的特征；揭示了水化学特征对盆地地下水流动系统的指示作用及地下水渗流场的空间演变规律；利用水位动态、同位素和水文地球化学模拟等多信息结合地下水渗流数值模拟模型进行识别和验证，定量或半定量地分析了地下水补给来源、补给方式、径流速度、径流途径、排泄方式及水化学演化的主要地球化学作用等。研究取得以下认识和结论：（1）忻州盆地第四系地下水系统外部相对独立，内部结构相对复杂。根据盆地构造底界势差可划分为繁峙断陷、代县凹陷、原平凹陷、奇村断阶、金银山隆起，忻定凹陷六个次级构造单元。区域上将其划分为三级地下水系统。（2）忻州盆地第四系孔隙水系统含水介质主要为冲洪积物，包括砂砾石、中粗砂、粉细砂、黄土、亚砂土、亚粘土、粘土。采用GMS5.0软件中的TINs模块和Solid模块构建了忻州盆地第四系地层和岩性三维可视化结构模型。（3）盆地内孔隙含水系统接受周边岩溶水系统、裂隙含水系统的侧向补给。忻州盆地地下水总体表现为由盆地周边山前倾斜平原区向中部冲积平原区汇集，并沿滹沱河现代河谷区由上游向下游径流。地下水的补给来源包括大气降水渗入补给、盆地周边地下水侧向径流补给、河渠渗漏补给、灌溉渗入补给和水库渗漏补给。地下水排泄途径主要有蒸发排泄、地表水、以泉的形式排泄和人工开采。（4）盆地系统地下水水位埋深由滹沱河谷两侧山前向盆地中心，变化范围由山前丘陵地区＞20m到河谷地带＜5m。浅层地下水位动态类型在山前倾斜平原上部属于入渗—径流型，在山前倾斜平原及冲湖积平原的大部分地区属于入渗—径流—开采型，在滹沱河现代河床两侧冲积平原区及冲洪积交接地带局部地段属于综合型；而中层地下水位动态类型在盆地周边山前倾斜平原上部属于入渗—径流—开采型，盆地的大部分地区属于径流型。（5）对忻州盆地进行了地下水均衡分析计算。2004年整个研究区内的水均衡分析计算结果表明，区内地下水总补给量为44104.35×10⁴m³／a，主要以降雨入渗和侧向流入为主，二者分别占总补给量的52.06％和26.52％，河道水库渗漏量、渠道渗漏和灌溉回渗分别占12.36％、3.92％和5.15％。总排泄量为44918.37×10⁴m³／a，其中地下水开采占总排泄量的56.01％，其次是地表基流量和潜水蒸发，分别占总排泄量的25.12％和18.85％。总体均衡误差为-1.78％，多年平均排泄量略大于多年平均补给量。（6）根据研究区的地下水流数值模拟模型，得到了典型地下水流动系统剖面渗流场特征。按照输出不同模拟层的地下水流速矢量，将流速范围＞0.7m／d、0.5～0.7m／d、0.2～0.5m／d、0.05～0.2m／d和＜0.05m／d分别划分为极强径流带、强径流带、一般径流带、弱径流带和极弱径流带。中层地下水平均水流速度较浅层地下水平均水流速度小。对浅层地下水而言，地下水在单元格（1×1km²）内穿过其中心节点地下水流径上的平均滞留时间变化范围是1.87～1361.95a；而中层地下水中地下水平均滞留时间变化范围是3.44～1440.94a。总体上，中层地下水比浅层地下水的平均滞留时间要长1.57～78.99a。（7）结合渗流场和水化学场特征，对忻州盆地典型地下水流动系统进行了系统划分。典型剖面流动系统研究表明，孔隙地下水流动系统在空间上存在着明显的级次性，即在阳武河洪积扇一带存在局部流动系统和中间流动系统，在原平大营断陷、奇村宽谷地带存在着局部流动系统、中间流动系统和区域流动系统。（8）对忻州盆地不同水体的主要水化学指标进行统计，分析了盆地内不同地下水流动系统的水化学分布特征，即地下水型、矿化度、宏量水化学组分Ca²⁺、Mg²⁺、Na²⁺、SO₄^2-、HCO₃^-、Cl^-、NO₃^-等离子含量的空间分布。探讨了地下水渗流场与水化学组分的关系。利用地下水中特殊离子成分（如Cl^-）和各类离子比值（如rCa／rNa、rMg／rNa、rCa／rCl、rNa／rCl、rSO₄／rCl、rHCO₃／rCl等）的标志作用，判断了盆地不同地下水流动系统中的水化学成分，总体上不仅受水动力条件、地下水位埋深以及地下水在径流途径上的沿程累积作用影响，存在有规律的变化，还受含水层介质矿物组成影响发生着不同程度的水文地球化学作用。在地下水流速缓慢的下游，地下水化学特征往往表现为局部流动系统或中间流动系统的排泄带特征，甚至可以代表区域流动系统的排泄带特征。（9）忻州盆地常温地下水、地下热水和地表水的稳定同位素δD和δ¹⁸O基本落在太原大气降水线上，标志着忻州盆地地下水以大气降水补给为主。本次研究建立了研究区降水高程方程，并计算所有水样的补给高程域。在补给高度为1300m以上时，补给高度与水中Na⁺和Cl^-离子成正比，与HCO₃^-离子成反比，表现为由地下热水的渗流途径要比冷水长的变化规律；而地下水中Ca²⁺、SO₄^2-、TDS含量随补给高程变化呈不同斜率增长，表现为由地下冷水到热水的所代表的地下水流动系统不同。大营断陷地下水系统与奇村宽谷地下水系统中，热水的水化学特征可以指示区域地下水流动系统的存在。（10）忻州盆地地表水样⁸⁷Sr／⁸⁶Sr比值比较低，为0.7125～0.7165；浅层水变化较小，⁸⁷Sr／⁸⁶Sr也低，为0.7171～0.7219；中层地下水含量变化较大，为0.7097～0.7307。热水的⁸⁷Sr／⁸⁶Sr比值可达0.7495，指示其参与区域地下水循环并在深大断裂裂隙热储中滞留时间长。通过⁸⁷Sr／⁸⁶Sr比值与Cl^-离子含量的相关分析表明，盆地（中间）地下水中SO₄^2-与⁸⁷Sr／⁸⁶Sr值都表现出良好的地下水流程信息，即与Cl^-呈正相关。此外，对不同水体与不同岩性的⁸⁷Sr／⁸⁶Sr比值变化范围对比研究，表明地表水和地下水中的溶质主要来源于硅酸盐岩和铝硅酸盐岩的风化或溶解，而碳酸盐矿物溶解对地下水化学组成的影响很小。（11）基于大营剖面地下水流动系统和阳武河洪积扇剖面流动系统，结合代表性水样点的水化学分析资料和地下水流数值模拟结果，如用流程→流速→滞留时间等确定反应路径，确定研究区的“可能矿物相”，利用PHREEQC2.11进行一维恒定流的情况下正向水文地球化学模拟。模拟结果表明，阳武河洪积扇地下水的流动速度比大营倾斜平原流动系统要快；揭示了不同系统不同层位的水化学作用机理；浅层地下水受到蒸发浓缩作用影响，可以采用土壤盐类综合体的溶解来表征；水化学模拟结果和实测分析结果基本一致，说明控制水流路径上水化学演化的主要地球化学作用有，CO₂的逸出，石膏、方解石、白云石、钠长石、斜长石、岩盐、萤石等的溶解，高岭石的沉淀、阳离子交换等。本文的主要特色体现在，（1）对整个忻州盆地地下水进行系统分析，确定第四系地下水系统的边界，然后将第四系孔隙地下水作为一个相对完整的地下水流动系统进行系统划分；（2）基于地下水系统理论框架，提取和分析含水介质结构、水动力场、水化学场（同位素）和温度场等信息，构建盆地地下水流模型；（3）综合运用多种方法校核地下水流数值模拟模型，包括平面上等水位线对比、点上动态曲线拟合、¹⁴C年龄推求地下水平均实际流速、Cl^-、⁸⁷Sr／⁸⁶Sr流程指示剂等；（4）通过典型剖面地下水系统渗流场和水化学物质反应—迁移模拟，探讨渗流场与化学场的耦合演变规律。更多还原

【Abstract】 The complexity and concealment of groundwater system make it difficult to fully understandgroundwater system. For a lone time, people have tried to use various methods to understandgroundwater system. But the only part information of the groundwater system can be obtained.Groundwater is the receptor and information carder in the environmental change. Based on thetheory of groundwater system, distilling and assimilating the isolated and scattered informationcan reduce the uncertainty, and can help us to accurately understand groundwater system in theoriginal. This study takes the porous groundwater in the whole Quartemary of Xinzhou basin as anexample to realize and research groundwater system in the integrated and systemic view,combining multitechniques with the traditional hydrogeological analysis to quantitatively distilland assimilate the scattered data.Xinzhou basin is a representative Cenozoic rift basin, located in the northernmost of FenheRiver rift valley in Shanxi Province, and belongs to the arid-semiarid region. Groundwater is theforemost source for water supply. With the double-quick development of the social economy andthe population augment since 1980s, the industrial and agricultural activity and mining made thewater resources requirement increased dramatically. Those have been profoundly changing thenatural environment of groundwater and regional water cycle condition. Groundwater resourcequantity, which can be utilized by human, have reduced by the incessant decline of thegroundwater level and the increasing deterioration of the groundwater quality in the basinQuaternary System. The industrial and agricultural developments in this region have seriouslyinfluenced by those phenomena, and some water resources and environmental problems occur. Theexploitation and utilization of water resources have been increasingly in conflict with theproduction practice due to the unreasonable water resource management and lack of environmentalprotection consciousness. So, it is necessary to research groundwater environmental evolutionunder the interaction between human activities and natural conditions. Most of the formerinvestigation and research in Xinzhou basin have been in the state of qualitative delineation togroundwater system using traditionally analytical hydrogeology methods, and formed differentcomprehensions about the rank demarcation of groundwater system. This research has reknowngroundwater flow system of Xinzhou basin in the view of systematic analysis.The study resultscan help us to correctly understand the three-dimensional hydrochemical field and explain thecomplex phenomena of regional hydrochemical characteristics. These will have certain theoreticalsignificance for revealing the source of groundwater environmental problems, and promoting the development of groundwater flow system theory. It will bring about the practical significance forrealizing the spatial-temporal evolution of groundwater resource and water cycle, and also for thedemonstration and decision-making of water resources development and utilization, and thesustainable use of water resources.Under the guidance of system theory, the porous groundwater in the whole QuarternarySystem of Xinzhou basin can be regarded as the research object to carry through the systemanalysis in this study. Groundwater flow model has been set up by distilling and analyzingmulti-information about the constitutes and structure of the water-bearing medium, boundaryconditions, and groundwater recharge, discharge, hydrodynamics and water balance. Somequalitative or semi-quantitative characteristics have been obtained by systematically analyzing thegroundwater flow field and hydrochemical field, including hydrogeochemical components andisotopes constitutes. The study shows that some hydrogeochemical characteristics can indicategroundwater flow system in the basin and spatial evolutionary rule of the groundwater flow field.Based on multi-information and multi-technique, such as groundwater level trends analysis, thestable isotopes analysis, radioactive isotopic age determination and hydrogeochemistry modeling,we distinguished and validated the groundwater numerical modeling and obtained somequantitative or semi-quantitative results, such as the recharge source of groundwater, rechargepattern, flow velocity, transit way, discharge modes and main hydrogeochemical action.Some major opinions and conclusions obtained in this research are as follows:（1） Groundwater system in Xinzhou basin is the nearly closed one with the relativelycomplex inner structure. According to the tectonic bottom boundary and potential difference, thebasin can be divided into six secondary tectonic units, namely Fanshi depression, Daixiandepression, Yuanping depression, Qicun rupture terrace, Jinyin upheaval and Xinding depression.In the regional scale, the groundwater system of Xinzhou basin was marked off for three ranks.（2） The main water-bearing medium of Quaternary porous-water system in Xinzhou basinare alluvium and proluvium, including coarse sand, middle and coarse sand, middle and fine sand,mealy sand, sabulous sand, mild clay, and clay. The models of stratum structure and lithologystructure of the Quaternary stratum in Xinzhou basin were set up by using TINs code and SOLIDcode in GMS5.0 software to realize three-dimension visualization.（3） According to the analysis of bedrock lithology in the mountain area around the basin, thehydrodynamic permeability of the strata combination of both planes of mountain front fault, wedeemed that porous water-bearing system of the basin gain the lateral recharge from the ambientKarst-water system and fracture water-bearing system. As a whole, groundwater in Xinzhou basingathers from the slant plain in the mountain front zone to the central alluvial plain, and flows alongthe modern valley from the upper to lower reaches of Hutuo River. The recharge source ofgroundwater includes atmospheric precipitation, lateral subsurface runoff from ambient mountainarea around the basin, leakage of rivers and reservoirs, irrigation percolation and channels leakage.The discharge way mainly includes evapotranspiration, surface base flow, springs and groundwaterexploitation.（4） The variation range of the depth of groundwater level in the basin is from more than 20meters in the hilly ground to less than 5 meters in the river valley zone. The dynamic type of the shallow groundwater belongs to the infiltration-runoff type in the upper piedmont plain, theinfiltration-runoff-exploitation type in the lower piedmont plain and most alluvial-lake plain, andthe comprehensive type in the both sides of the modern riverbed of Hutuo river and the localsection of the alluvial transition zone. But for the middle groundwater, the dynamic type is theinfiltration-runoff-exploitation type in the lower piedmont plain, and the subsurface runoff type inthe most area of the basin.（5） The results of the calculation of the water balance during 2004 in Xinzhou basin showthat the total recharge of groundwater is 441.04x10⁶m³/a, mainly including the rainfall infiltrationand lateral influx, about 52.06% and 26.52% respectively of the total recharge. Among the otherrecharges, leakage of rivers and reserviors, channels leakage and seepage irrigation return accountfor 12.36%, 3.92% and 5.15%, respectively. And the total discharge of groundwater is449.18x10⁶m³/a, of which about 56.01% is artificial exploitation. Other discharge items, such assurface base flow and evaporation of phreatic water account for 25.12% and 18.85% respectively.As a whole, balance error is-1.78%, and the mean annual discharge is more than the meanrecharge in Xinzhou basin.（6） Through groundwater flow numerical modeling, we can attain some characteristics on thetypical groundwater flow cross-sections. According to the output of the actual velocity ofgroundwater, the velocity range of＞0.7m/d, 0.5～0.7m/d, 0.2～0.5m/d, 0.05～0.2m/d and＜0.05m/dare defined as supper-strong runoff zone, strong runoff zone, general runoff zone, weak runoffzone and supper-weak runoff zone respectively. The average flow velocity in the middlegroundwater is lower than that in the shallow groundwater. For the shallow groundwater, thevariation range of the average residence time, namely the time that groundwater flow needs alongthe pathline through central node of one cell （1×1km²） , is 1.87～1361.95a. But for the middlegroundwater, the variation range of the average residence time is 3.44～1440.94a. Generally, theaverage residence time in the middle of groundwater is longer than that in the shallow groundwater,and its range is from 1.57 to 78.99a.（7） Integrating groundwater flow field with the characteristics and hydrochemical field todemarcate the groundwater flow system of Xinzhou basin, we found that there exists the obviousranks in the space of the loose porous groundwater flow system. The study result of typicalprofiles of groundwater flow system show that there are local flow system and middle flow systemin the proluvial fan of Yangwu river, and there are local flow system, middle flow system andregional flow system in Daying depression and Qicun rupture terrace.（8） The hydrochemical distribution characteristics, in the different groundwater flow systemsof the basin, can be obtained from the statistical analysis to the hydrochemical index of the watersamples from the different water body in Xinzhou basin. These characteristics include that thespatial distribution of the water type, total dissolved solid （TDS）, and the concentration of majorhydrochemical components (such as Ca²⁺, Mg²⁺, Na⁺, SO₄^2-, HCO₃^- Cl^- and NO₃^-), alsoinclude the relationship between groundwater flow field and hydrochemical components. Inaddition, the indicative action of special ion （such as Cl^-） and the different ion concentration ratio,such as rCa/rNa, rMg/rNa, rCa/rCl, rNa/rCl, rSO₄/rCl and rHCO₃/rCl, can be used to judge thespatial hydrogeochemical evolution action of groundwater system, and indicative significance to groundwater flow field. In the lower reaches of the basin, the flow velocity of groundwater isususally slow, and the hydrochemical characteristics can represent the features of the dischargearea in the local flow system or the middle flow system, even the regional flow system.（9） TheδD andδ¹⁸O values for the normal groundwater, thermal groundwater and surfacewater in Xinzhou basin plot in close proximity along Taiyuan meteoric water line. This indicatedthat the recharge of groundwater in this basin is mainly controlled by the atmospheric precipitation.In this study, we obtained the precipitation elevation equation of the study area and calculated therange of recharge elevation of water samples. The concentration of Na⁺ is in direct proportion tothat of Cl^- and in inverse proportion to that of HCO₃^- when the recharge elevation is more than1300m. This also shows that the transit distance of the thermal water is longer than the coldgroundwater. In addition, the content of Ca²⁺, SO₄^2- and TDS increase by the different rate of slopeas the change of the recharge elevation. And it reveals that the cold groundwater and the thermalwater are from the different groundwater flow systems. This point can be identified fromgroundwater system of Daying depression and Qicun rupture terrace, and shows that there are theregional groundwater flow systems indicated by the hydrogeochemical characteristics of thermalwater.（10） The ⁸⁷Sr/⁸⁶Sr ratio of surface water in Xinzhou basin is relatively low, and its range is0.7125～0.7165. There is little change in the ⁸⁷Sr/⁸⁶Sr ratio of the shallow groundwater with therange from 0.7171 to 0.7219. The ⁸⁷Sr/⁸⁶Sr ratio of the middle groundwater is changed from0.7097 to 0.7307. The ⁸⁷Sr/⁸⁶Sr ratio of the thermal water is up to 0.7495 and shows that thethermal waters participate in the regional groundwater circulation with the long residence time inthe thermal storage of deep fault fissures. The correlation analysis to the ⁸⁷Sr/⁸⁶Sr ratio, the contentof Cl^- and SO₄^2- ion shows that SO₄²- and the ⁸⁷Sr/⁸⁶Sr ratiodisplay good information ofgroundwater flow, namely with the positive correlation to Cl^-. By contrasting the range of the⁸⁷Sr/⁸⁶Sr ratio in the different water samples with that in the different lithology, the researchindicates that the solute in the surface water and groundwater mainly from the weathering ordissolving of silicate rocks, and aluminum silicate rock, while there is little impact on thehydrochemical composition of groundwater caused by the dissolved carbonate minerals.（11） Based on the typical groundwater flow system profiles of the Daying and the proluvialfan of Yangwu river, combining the hydrochemical analysis of the representative water sampleswith the result of groundwater flow modeling, the reaction path can be confirmed by flow path,flow velocity and residence time. The "possible mineral phase" can also be confirmed according tothe composition of lithology minerals in the aquifers and its geochemical features. Forwardhydrogeochemistry modeling can be implemented by using PHREEQC2.11 software underone-dimensional invariable velocity. The modeling results show that the flow velocity in theproluvial fan of Yangwu river is faster than that in Daying piedmont plain, and reveal themechanism of hydrochemistry in the different levels in the different groundwater flow system.Shallow groundwater is influenced by the evaporation and concentrated role, and the dissolution ofsoil salts can be used to characterize this impact. The calculated quantitative results fromhydrogeochemistry modeling accord with the measured results. This shows that the majorgeochemical actions, which control hydrogeochemical evolution along groundwater flow path, include CO₂ gaseous escape, the dissolution of gypsum, calcite, dolomite, albite, plagioclase, haliteand fluorite, precipitation of kaolinite and illite, and cation exchange reaction.The major advances achieved in this thesis are as follows: （1） The porous groundwater in thewhole Quarternary System can be regarded as an integrated groundwater flow system and bedemarcated by analyzing groundwater in the whole Xinzhou basin. （2） Based on the frame ofgroundwater system theory, groundwater flow model has been built up by distilling and analyzingscattered and single multi-information about bearing water medium, flow field, hydrogeochemistry（include isotope） and temperature field. （3） A suit of integrated methods for calibratinggroundwater flow numerical modeling have been applied in this thesis, such as contrasting waterlevel contour maps in different depth, fitting water head trends-curves on typical observation well,estimating the average practical velocity of groundwater flow by ¹⁴C age, judging groundwatertransit distance by Cl^- and ⁸⁷Sr/⁸⁶Sr. （4） Coupled evolutionary characteristics have been discussedby groundwater flow modeling and hydrogeochemical reaction-transport modeling on the typicalgroundwater system profiles.更多还原