马镇渗流井现场试验研究

发布时间：2018-06-02 07:35

本文选题：渗流理论 + 渗流—管流耦合模型　；参考：《长安大学》2017年硕士论文

【摘要】：陕北地区尤其是黄土丘陵区水资源总体上比较匮乏,开发难度大,随着陕北能源化工基地建设的加快,供不应求的水资源将制约陕北能源化工基地发展。因此,加快推进陕北能源化工基地建设,必须科学地开发水资源以此保障其可持续发展,沿黄河渗流井取水方式是近期解决水资源短缺问题的有效方式之一。马镇渗流井位于神木县东部黄河沿岸,含水层以第四系冲洪积层孔隙潜水含水层以及三叠系碎屑岩类裂隙水含水层为主,透水性较好,地下水补给条件好,具有很好的供水意义。本文以渗流理论为指导,对渗流井取水条件下周边三维渗流场特征及变化规律进行现场试验研究,并采用数值模拟方法对抽水试验结果进行仿真模拟,建立可靠的基于“渗流-管流耦合模型”渗流井取水计算模型,用于探索渗流井建立在不同含水层岩性中取水的优化设计方案,为提高渗流井取水效率提供指导。通过渗流井周围设置的分层观测孔资料,分析了阶梯状稳定流抽水试验过程中地下水三维渗流场特征:在抽水过程中第四系地层中的地下水位的变化明显随着黄河水位的波动而变化,在时间上表现略有滞后,说明了河水对地下水有强烈的补给作用;渗流井抽水时,各含水层之间存在水头差,并且随着开采量的增加水头差也在增加,表明无论在未来开采或者天然状况下,黄河河水补给地下水都是以三维流的运动方式进行的;渗流井开采地下水时,对黄河对岸的地下水影响甚微。通过对研究区地质条件、气象条件以及水文地质条件等的理解认识上,采用地质雷达和钻孔揭露地层建立三维地层结构模型模型,同时以“渗流—管流耦合模型”理论为基础,建立渗流井取水工程三维水文地质数值模型。使用现场抽水试验资料进行模型识别,对三个落程渗流井出水量进行拟合,反求出水文地质参数。在此基础上,设计优化方案:不同辐射孔仰角方案、相同布设段长度不硐室间距方案、不同辐射孔个数方案。通过计算对比,在考虑施工难度和成本的前提下,在辐射孔伸入第四系长度相等的情况下,辐射孔角度在20°-30°之间取水效果较好;硐室间距在70m-100m之间渗流井取水效果较好;增加辐射孔个数可以增加渗流井出水量,但是辐射孔个数增加到一定程度,渗流井取水量增加的效果不是很理想,反而会增加施工的难度和成本。通过水文地质参数不稳定性分析以及不同河流渗透能力渗流井出水量方案的对比结果,在渗流井设计时,要加强前期的水文地质勘察,尽可能准确的获取研究区的水文地质参数,提高渗流井的出水效率。
[Abstract]:Water resources in northern Shaanxi, especially in loess hilly areas, are relatively scarce in general and difficult to develop. With the acceleration of the construction of energy and chemical industry base in northern Shaanxi, the shortage of water resources will restrict the development of energy and chemical industry base in northern Shaanxi. Therefore, in order to speed up the construction of energy and chemical industry base in Northern Shaanxi, it is necessary to develop water resources scientifically to ensure its sustainable development. The way of taking water from percolating wells along the Yellow River is one of the effective ways to solve the problem of water resources shortage in the near future. Mazhen percolation well is located along the Yellow River in the eastern part of Shenmu County. The aquifer is mainly composed of phreatic aquifer of Quaternary flood accumulation layer and fissure water aquifer of clastic rock of Triassic system, which has good permeability and good recharge condition of groundwater. Have very good water supply meaning. Under the guidance of seepage theory, the characteristics and variation of three dimensional seepage field around the percolation well are studied in this paper, and the results of pumping test are simulated by numerical simulation method. A reliable seepage well water intake calculation model based on "coupled seepage and pipe flow model" is established, which can be used to explore the optimal design scheme of water intake in different aquifer lithology, and to provide guidance for improving the water intake efficiency of percolation well. Through the stratified observation hole data around the percolation well, The characteristics of three dimensional seepage field of groundwater during the pumping test of stepped steady flow are analyzed. The variation of groundwater level in Quaternary strata obviously changes with the fluctuation of the water level of the Yellow River during the pumping process, and shows a slight lag in time. It is shown that the river has a strong recharge effect on the groundwater, and when the percolation well is pumped, there is a water head difference between the aquifers, and the water head difference also increases with the increase of the mining capacity, indicating that no matter in the future exploitation or in the natural condition, The recharge of groundwater in the Yellow River is carried out by the movement of three-dimensional flow, and the groundwater on the other side of the Yellow River has little effect when the seepage wells are used to exploit the groundwater. Based on the understanding of geological conditions, meteorological conditions and hydrogeological conditions in the study area, a three-dimensional stratigraphic structure model is established by using geological radar and borehole disclosing strata, and based on the theory of "seepage and pipe flow coupling model". A three-dimensional hydrogeological numerical model of seepage well water intake project is established. The model identification is carried out by using field pumping test data, and the hydrogeological parameters are obtained by fitting the water output of three falling percolation wells. On this basis, the optimization scheme is designed: different elevation angle scheme of radiation hole, no chamber spacing scheme of the same length of layout section, and different number of radiation holes scheme. Through calculation and comparison, under the premise of considering the difficulty and cost of construction, when the length of the radiation hole is equal to that of the Quaternary system, the water intake effect of the radiation hole angle is better between 20 掳-30 掳, and the water intake effect of the percolation well between the 70m-100m and the chamber spacing is better. Increasing the number of radiation holes can increase the water output of percolation wells, but increasing the number of radiation holes to a certain extent, the effect of increasing the water intake of percolation wells is not very ideal, on the contrary, it will increase the difficulty and cost of construction. Based on the analysis of the instability of hydrogeological parameters and the comparative results of water output schemes of seepage wells with different permeable capacity of different rivers, the preliminary hydrogeological investigation should be strengthened in the design of percolation wells. The hydrogeological parameters in the study area are obtained as accurately as possible to improve the effluents efficiency of percolation wells.
【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】：P641.8;TU991.12

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