基于砂槽模型的地下水流系统特征研究

发布时间：2018-06-30 03:21

  本文选题：地下水流系统 + 砂槽模型　； 参考：《成都理工大学》2017年硕士论文

【摘要】：地下水流系统发育受控于地形、入渗强度和渗透性、介质场长深比和势汇等因素,国内外的研究学者针对这些影响因素和系统水动力特征方面做了诸多针对研究。在区域地下水流长途径的流动过程中,水-岩作用使得水流的浓度逐渐发生改变,介质的渗透性发生变化;水库蓄水抬升河谷区地表水水位,系统的势汇条件发生变化,造成深部区域性地下水和浅层地下水的水动力特征发生改变。目前极少有学者从区域性水流其自身特有的浓度特征和工程中地表水水位变化角度下考虑地下水流系统的变化研究。本论文在总结国内外地下水流系统理论研究的基础上,通过对系统的影响因素、地质原型的分析,选择褶皱类型系统作为试验概化原型。通过概化地形、势汇这两个最为主要的控制因素,基于室内砂槽模型试验,对浓度和地表水水位变化过程进行物理模拟,结合图像处理技术,分析系统的变化特征,得到以下结论。(1)随着区域性水流浓度的升高,区域系统内的流线向下移动明显,浅层局部流线下移不明显,局部系统与区域系统的分界线处存在浓度梯度。区域系统内水质点的平均渗流速度降低,区域系统的循环流量减少。局部排泄点的排泄量由最初占比46.80%逐渐增加到63.80%,相应的区域排泄点的排泄量占比从53.20%下降到37.20%。(2)在试验Ⅰ-2模拟的水流系统中,共存在3个驻点,分别为在(0,0)和(100,0)位置的两个区域驻点和在(60.1,35.1)附近的局部驻点SP。(3)液体粘滞系数增加对渗流速度的影响大于密度的影响,密度流中水质点的渗流速度较淡水明显增大。单位重量液体在地表位置进入至最低位置时,水头损失?将会增大。(4)区域排泄河谷内地表水水位抬升,造成属于浅层局部和区域系统的流线向上偏移,属于深部区域系统的流线变化不明显。在排泄区附近,浅层区域系统和局部系统的流线变化特征相似。区域系统内1号流线上质点的平均渗流速度降低29.26%,局部系统L2中5号流线上质点平均渗流速度增加18.5%,局部系统L3中6号流线上质点平均渗流速度减小13.40%。区域排泄点的排泄量减少,局部排泄点的排泄量增加。(5)排泄点地表水水位抬升,对排泄点附近的地下水水位影响最为明显,其直接影响为水力梯度的减小,造成各水流系统的流量发生变化。
[Abstract]:The development of groundwater flow system is controlled by topography, infiltration intensity and permeability, the ratio of medium field length to depth and potential sink, and so on. Domestic and foreign researchers have done a lot of research on these factors and the hydrodynamic characteristics of the system. In the course of regional groundwater flow, the water-rock interaction changes the concentration of water flow gradually, the permeability of medium changes, and the water level of surface water in the valley area is raised by reservoir, and the potential sink condition of the system changes. The hydrodynamic characteristics of deep regional groundwater and shallow groundwater are changed. At present, very few scholars consider the change of groundwater flow system from the angle of regional water concentration characteristics and surface water level variation in engineering. On the basis of summarizing the theoretical research of groundwater flow system at home and abroad, this paper selects the fold type system as the experimental generalization prototype through the analysis of the influence factors and geological prototype of the system. Based on the indoor sand tank model test, the variation process of concentration and surface water level is simulated physically by means of generalized terrain and potential sink, and the variation characteristics of the system are analyzed with image processing technology. The following conclusions are obtained: (1) with the increase of regional water concentration, the flow line in the regional system moves down obviously, but the local flow line in the shallow layer does not move down obviously, and there is a concentration gradient at the boundary between the local system and the regional system. The average percolation velocity of the water quality points in the regional system is decreased, and the circulating flow rate of the regional system is decreased. The amount of local discharge point gradually increased from 46.80% to 63.80%, and the proportion of local discharge point decreased from 53.20% to 37.20%. (2) in the flow system simulated in experiment 鈪，

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