【作者】 陈添斐；

【导师】 万力； 王旭升；

【作者基本信息】 中国地质大学（北京） ， 地下水科学与工程， 2014， 博士

【摘要】 陆面蒸散包括植物蒸腾和土面蒸发，与地下水埋深具有显著的关系。同时，地下水的分布和运动方式强烈受到蒸发的影响。因此，研究地下水与陆面蒸散的相互作用对于陆面水文循环、区域水资源评价、协调社会用水和生活用水等具有重要的理论意义和实践意义。考虑入渗和线性蒸发，建立单井开采稳定流模型，获得地下水位和对流运移时间的解析解，同时，构建一个假想的例子，运用MODFLOW和MODPATH进行数值模拟，验证了解析解的准确性。将群丼开采概化为理想圆形面状开采，考虑入渗和线性蒸发的垂向通量，分别获得低、中、强抽水速率下水位和蒸发速率分布的解析解，并与数值模拟结果进行对比，两者吻合度很好。考虑抛物线型和指数型蒸发条件，运用Runge-Kutta数值算法获得地下水位和蒸发速率的分布，与线性蒸发相比，三者的水位分布几乎一致，地下水蒸发的重分布形式相似。根据鄂尔多斯高原观测孔的地下水位资料，建立解译地下水动态的概念模型，分析周期动态的参数敏感性和气候敏感性，蒸发的极限埋深Dmax和权重值主要改变水位的平均埋深，给水度则主要改变水位埋深的振幅。在此基础上，分别建立单井开采、群井开采和大口井开采的动态叠加模型，运用MODFLOW进行数值模拟，结果表明抽水井开采会同时改变地下水位的埋深、振幅和相位，开采扰动程度主要受距井的距离和开采井类型的影响。根据干旱区湖泊主要接受降雨入渗和进行蒸发排泄的特点，分别建立潜水含水层和有越流含水层的湖泊蒸发模型，在数值模拟中将湖泊等效处理为大口井，模拟结果显示含水层结构的改变对湖水位和地下水位分布的影响甚小。同时，将大口井模型和湖泊模型进行类比分析，两者具有一定的相似性，但由于水体规模存在很大的差异，导致地下水动态特征有所不同。选取巴丹吉林沙漠的典型湖泊-苏木巴润吉林，野外实测湖泊的温度和盐度，分析了水温和矿化度的空间变化特征，湖底矿化度的异常低值区可能存在深部地下水的集中排泄。建立沙漠湖泊群与地下水流场的耦合模型，集中讨论数值模型中湖泊的处理方法，分析地下水流场特征，总体上沙漠地下水由东南流向西北。更多还原

【Abstract】 Evapotranspiration, which includes plant transpiration and soil evaporation, has aclose connection to groundwater depth. At the same time, evapotranspiration stronglyinfluences the distribution and movement of groundwater. As a result, study oncoupling between groundwater and evapotranspiration gives theoretical and praticaldirection for analyzing land surface hydrological cycle, evaluating regional waterresources and coordinating the relationship between social and ecological water use.A mathematical model of unconfined flow toward a discharge well withredistribution of groundwater evapotranspiration is developed. Analytical solutions ofgroundwater level and travel time are obtained. For a typical hypothetical example,these solutions perfectly agree with the numerical simulation results based onMODFLOW and MODPATH. A mathematical model of steady radial flow toward agroup of wells considering recharge and evapotranspiration is developed. The wellfield is simplified by a circular area with uniformly distributed pumpage. Analyticalsolutions for three cases with low，medium and strong pumpage are obtained, whichsufficiently agree with a numerical model. Runge-Kutta solutions of using nonlinearevapotranspiration formulas are presented and compared with the analytical model.They predict almost the same water table distribution and similar redistributionpatterns of evapotranspiration.Based on the data of groundwater level in Ordos Plateau, a concept model whichinterprets the dynamic characters of groundwater is built. The parameter sensitivityand climate sensitivity are analyzed. Among them, Dmax and mainly change theaverage of groundwater depth while mainly changes the amplitude of groundwaterdepth. Then, dynamic superimposed models of a pumping well, large-diameter welland a group of wells are built separately. Based on MODFLOW，the numericalsimulation results show that pumping changes the average, amplitude and phase ofgroundwater level. Furthermore，the magnitudes of the changes are mainly controlledby the distance to the well and the type of the well.The concept models of lakes locating in unconfined aquifer and leaky aquifer are developed separately. In arid areas, precipitation and evapotranspiration are mainsources of lakes, so lakes are considered as large-diameter wells in the numericalsimulation. The results show that the change of aquifer settings takes little effect on thedistribution of groundwater. Then, a model of a large-diameter well capturinggroundwater evapotranspiration is developed and compared with the lakeevapotranspiration model. These two models perform similarly in general，but thesignificant differences in water volume lead to different characteristics of groundwaterdistribution.In this study, a survey of the depth-dependent temperature and electricconductivity was carried out in the typical salt lake: the Sumu Barun Jaran. Spatialdistributions of temperature and salinity are investigated. Abnormal low TDS zonesdeveloped in the water body near the lake bottom which seem to be influenced bygroundwater and indicate concentrated discharge of groundwater into the lake. Further,a coupling model between desert lakes and groundwater flow is developed. Thesimulation method of lakes is discussed and the character of groundwater flow field isanalyzed. On the whole, groundwater flows from southeast to the northwest.更多还原