柴达木盆地德令哈断陷区地下水流动系统研究

发布时间：2018-07-04 20:12

本文选题：德令哈断陷 + 地下水流动系统　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：地下水存在于地下的多孔介质中,其流动特点具有隐蔽性以及复杂性,易受地层的发育分布特征、埋藏深度分布性质以及地形地貌特征等因素的影响。柴达木盆地德令哈断陷地区地层构造复杂,多处发育断层。在地层垂向上岩性性质变化大,埋藏深度情况很大时,二维地下水流模型就能比较好的反映该类研究区的地下水流动系统特征。本次选取德令哈断陷区内一条典型剖面,利用GMS软件在剖面上建立二维稳定水流模型,较详细地研究了德令哈断陷地区地下水流动系统,并结合剖面水化学对剖面地下水补给排泄特征和地下水流动系统做出合理分析,这更加真实的还原了德令哈断陷地区的地下水循环规律。从剖面上水流模拟结果看出:(1)宗务隆山前通过大气降水和冰雪融水补给成为剖面上主要的地下水补给区,山前倾斜平原有部分地下水溢出,剖面上最低处的托素湖和克鲁克湖成为地下水主要排泄区,排泄强度比较集中。(2)地下水在含水介质通道流动过程中,发育着局部、中间和区域三级循环系统,在各级循环系统中,区域循环系统的地下水流动流量占整个剖面总流量的5%左右,其他两级循环系统的地下水流量占95%左右,说明地下水流动以局部和中部循环为主。(3)剖面水化学分析结果与模型揭示的剖面水循环特征互相对应。地下水水化学类型从山前到盆地平原中部流动过程中,具有明显的变化规律。宗务隆山山前,地下水垂向交替强烈,水质好,多为TDS在550mg/L以下HCO_3型水,水流速度快,更新速率快,循环强度明显高于深层水。在克鲁克湖溢出带以北,山前倾斜平原中部,浅层含水层主要水化学类型为TDS大于3000mg/L的SO_(4-)HCO_3型水,有地下水排出地表发生蒸发作用。在托素湖排泄区,地下水以垂向流动为主,浅层地下水水化学类型为TDS大于2000mg/L的Cl-Na型水。(4)从石炭系含水层中地下水的运移时间和渗透流速分布图中知,区域单元格B处地下水平均运移时间最长,平均渗透速度非常慢,从而地下水循环更新能力在该处最慢,封闭性相对比较好。
[Abstract]:Groundwater exists in the porous media in the underground, its flow characteristics are concealed and complex, easily affected by the characteristics of the development and distribution of the strata, the characteristics of the buried depth distribution and the topography and geomorphology. The formation of the Delingha faulted area in the Qaidam Basin is complex and many faults are developed, and the lithologic property of the strata is changed vertically. The two-dimensional groundwater flow model can better reflect the characteristics of the groundwater flow system in this kind of research area. A two-dimensional stable flow model is established by GMS software in the section of the Delingha fault subsidence area, and the groundwater flow system in the Delingha fault subsidence area is studied in detail. Based on the cross section hydrochemistry, it makes a reasonable analysis of the characteristics of groundwater recharge and excretion and the groundwater flow system, which is more true to restore the law of groundwater circulation in the Delingha fault subsidence area. The results of the flow simulation on the profile show that: (1) the major gas precipitation and ice snow melt water supply before the Longshan mountain is the main section on the section. In the groundwater recharge area, there are some groundwater spillovers in the sloping plain in the front of the mountain, and the main drain area of the groundwater in the lowest section of the section of the section is the main discharge area of the groundwater. (2) in the course of the flow of the aquifer channel, the groundwater is developed in a local, intermediate and regional three cycle system, and the regional circulation is circulated in the circulation system at all levels. The groundwater flow of the system accounts for about 5% of the total flow of the whole section, and the groundwater flow of the other two cycle systems accounts for about 95%, indicating that the groundwater flow is mainly in the local and central circulation. (3) the results of the hydrochemical analysis of the section and the characteristics of the water cycle revealed by the model correspond to each other. The hydrochemical types of groundwater from the front to the basin In the process of central plain flow, there is obvious change law. In the Longshan mountain of Zong Wu, the vertical alternation of groundwater is strong, the water quality is good, and the TDS water is below 550mg/L. The water flow speed is fast, the rate of renewal is fast, and the cycle strength is obviously higher than the deep water. The study type is SO_ (4-) HCO_3 type water with TDS greater than 3000mg/L, which has the effect of evaporation from ground water. In the drainage area of Toru lake, the groundwater is dominated by vertical flow, and the hydrochemical type of shallow groundwater is Cl-Na type water with TDS greater than 2000mg/L. (4) the migration time of groundwater in the Carboniferous aquifer and the distribution map of seepage flow velocity are known. The horizontal migration time of the domain cell B is the longest and the average permeation speed is very slow, thus the groundwater circulation renewal capacity is the slowest and the sealing ability is relatively good.
【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】：P641.2

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