新疆伊犁—巩乃斯河河床沉积物渗透系数空间变异性及河水与地下水转化关系

发布时间：2018-11-27 10:15

【摘要】：新疆伊犁河谷地处我国西北干旱绿洲区,欧亚大陆腹地,气候温和湿润,水土资源丰富。然而随着区域社会经济的发展,对水资源的需求不断增大,水资源的不合理开发利用引发的生态环境问题也逐渐显现。伊犁河河水是地下水的主要补给项与排泄项,河水与地下水的关系密切且转化频繁。而不同区域河床沉积物渗透系数的大小又决定了河水与地下水水力联系的强弱及转化强度的大小。因此,开展区域河床沉积物渗透系数空间变异性以及河水与地下水转化关系的研究具有重要的理论与实践意义。本文选取新疆伊犁—巩乃斯河为研究对象,调查分析了伊犁—巩乃斯河谷水文地质条件,采用降水头竖管试验法、多孔介质垂向渗透仪法、颗粒分析法以及双环试验法四种方法测定河床沉积物垂向渗透系数Kv,通过对比分析及统计学方法研究了Kv空间变异性;用温度示踪法研究河水与地下水转化关系。研究表明:(1)四种不同试验方法所测渗透系数结果相差不大,基本小于5 m/d,较符合实际结果。按所测试的Kv值从大到小排列测试方法依次为双环试验法、垂向渗透仪试验法、降水头竖管试验法,其中颗粒分析法试验结果误差最大。(2)在伊犁—巩乃斯河谷,无论是垂直河道方向的河南、北两岸,还是沿河道方向由上游到下游,其渗透系数均服从正态分布。且沿河道方向利用降水头竖管试验法测试的垂向渗透系数的正态检验结果比垂直河道方向的Kv更符合正态分布。(3)通过传统统计学方法对伊犁—巩乃斯河谷河床沉积物渗透系数的空间变异性分析,无论是垂直河道方向的河南、北两岸,还是沿河道方向由上游到下游,其渗透系数变异性为中等-强。且沿河道方向的渗透系数空间变异性强于垂直河道方向,上游沉积物渗透系数的空间变异性强于下游。(4)由温度示踪试验测试的浅层地下水温度随时间及深度的变化曲线可以发现,河水接受地下水补给时,浅层地下水温度受热量交换影响较大,波动较显著;河水补给地下水时,浅层地下水温度受地下水温度的缓冲作用,其波动较平缓。(5)通过温度示踪法及水动力学方法求解河水与地下水垂向交换渗流速度,介于0—8 cm/d间,并对其结果进行对比,可以发现二者结果基本吻合。温度示踪法作为一种新兴的水文地质方法,在河床交互带地表水与地下水转化关系及水动力交换量的计算中有较高的准确性。
[Abstract]:Xinjiang Yili River Valley is located in arid oasis region of northwest China, Eurasia hinterland with mild and humid climate and abundant soil and water resources. However, with the development of regional society and economy, the demand for water resources is increasing, and the ecological environmental problems caused by unreasonable exploitation and utilization of water resources are also gradually appearing. Yili River is the main recharge and discharge of groundwater. The permeability coefficient of river bed sediment in different regions determines the hydraulic relation between river water and groundwater and the intensity of transformation. Therefore, it is of great theoretical and practical significance to study the spatial variability of regional river bed sediment permeability coefficient and the relationship between river water and groundwater conversion. In this paper, the hydrogeological conditions of Yili Gongnisi River valley in Xinjiang are investigated and analyzed. The vertical percolation method of porous media and the vertical penetrameter of porous media are used to test the hydrogeological conditions of the river. The vertical permeability coefficient (Kv,) of riverbed sediment was measured by particle analysis and double loop test. The spatial variability of Kv was studied by comparative analysis and statistical method. The relationship between river water and groundwater was studied by temperature tracer method. The results show that: (1) the osmotic coefficient measured by the four different test methods has little difference and is less than 5 m / d, which is in good agreement with the actual results. According to the Kv values measured from large to small, the order of test methods are double loop test, vertical osmometer test and vertical precipitation head test, among which the particle analysis method has the largest error. (2) in the Yili-Gongnays valley, No matter the perpendicular channel direction of Henan, the north banks or the direction of the river channel from upstream to downstream, the permeability coefficient is from normal distribution. The vertical permeability coefficient measured by vertical pipe test along river channel direction is more consistent with normal distribution than Kv in vertical channel direction. (3) the traditional statistical method is applied to the Yili-Gunas valley. Spatial variability analysis of permeability coefficient of river bed sediment, The variation of permeability coefficient is medium-strong both in the north bank and in the river channel direction from upstream to downstream. The spatial variability of the permeability coefficient along the channel direction is stronger than that along the vertical channel direction. The spatial variability of the permeability coefficient of the upstream sediment is stronger than that of the downstream. (4) the variation curve of the temperature of shallow groundwater with time and depth measured by temperature tracer test can be found that, when the river water receives groundwater recharge, The temperature of shallow groundwater is greatly affected by heat exchange and fluctuates significantly. When a river recharges groundwater, the temperature of shallow groundwater is cushioned by the temperature of groundwater, and its fluctuation is relatively smooth. (5) the vertical exchange seepage velocity between river water and groundwater is calculated by temperature tracer method and hydrodynamic method. The results between 0-8 cm/d and 0-8 cm/d were in good agreement with each other. As a new hydrogeological method, the temperature tracer method has high accuracy in the calculation of the relationship between surface water and groundwater and the calculation of hydrodynamic exchange volume in the river bed interaction zone.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P641.2

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