北票反向渗滤取水工程取水量的计算方法研究

发布时间：2018-11-12 17:31

【摘要】：本文以北票市白石水库反向渗滤取水工程为实例，结合室内渗流场模拟试验，并以多孔介质地下水渗流的基本原理为指导，分析室内模拟试验的渗流场形态，进而对反向渗滤取水工程的取水量影响因素进行分析研究。采用不同解析法对渗流场取水量进行计算，并将计算结果与试验实际出水量进行分析、对比。在此基础上，引入Visual Modflow对北票反向渗滤取水工程的取水过程进行数值模拟，通过分析渗流场形态，进行水量计算。根据上述研究内容和步骤，得到以下结论：（1）反向渗滤取水的渗流场具有典型的三维饱和稳定流特征；反向渗滤取水滤床中的地下水与河流的水力联系比较密切，滤床中的地下水处于承压状态。（2）反向渗滤取水的出水量的补给来源以河水的激发入渗为主，河床底部砂卵砾石层中的地下潜流补给次之。（3）抽水初期的短时间内的出水量主要由滤床砂层的静储量提供，此时渗流场发生极大的降深。随着河水的激发入渗补给，水位降深逐渐趋于稳定，并随时间的持续逐渐向滤床底部扩展。（4）取水管在取水的同时也激发河流的入渗补给，导致在取水管附近形成一个低势区。不管取水量有多大，越靠近取水滤管区域，则水头降深变化范围越大，，水力坡度越大；在远离取水滤管区域，取水的影响很小，其水力坡度很小。（5）采用承压非完整井单井抽水法、大口井、渗渠类比、垂向入渗系数法及辐射井公式替换法共五种不同数学解析法对室内模拟试验的渗流场的出水量进行计算、对比。由于不同解析式在水文地质参数取值上的差异性，不同解析法的计算值与实际出水量存在不同比例的差值：渗渠类比公式计算方法的差值最大；承压非完整井单井抽水法、大口井法、辐射井公式替换法的差值次之；垂向入渗系数法的差值最小。（6）通过引入数值模拟方法，对北票反向渗滤取水工程取水量进行数值模拟计算，采用Visual Modflow软件建立了工程区模型。通过模型空间离散、边界概化、水文地质参数选取、模型方案设计及其基本模型的校验，确定了模型在北票反向渗滤取水工程区的可靠性。在此基础上，通过对北票反向渗滤取水工程在单硐室抽水和多硐室同时抽水下的取水量进行数值模拟方法的计算，确定数值模拟方法在渗滤取水工程取水量的计算中适用范围较广，计算的结果的可靠性较高。
[Abstract]:Taking the reverse percolation project of Beipiao Baishi Reservoir as an example, combined with the indoor seepage field simulation test and guided by the basic principle of porous medium groundwater seepage, the paper analyzes the seepage field pattern of the laboratory simulation test. Furthermore, the factors affecting the water intake of reverse leachate are analyzed and studied. Different analytical methods are used to calculate the water intake of seepage field, and the calculated results are compared with the experimental results. On this basis, Visual Modflow was introduced to simulate the water intake process of Beipiao reverse percolation project, and the water quantity was calculated by analyzing the seepage field shape. According to the above research contents and steps, the following conclusions are obtained: (1) the seepage field of reverse percolation has typical three-dimensional saturated steady flow characteristics; The groundwater in the reverse percolation filter is closely related to the hydraulic relation of the river, and the groundwater in the filter bed is in a confined state. (2) the main recharge source of reverse percolation is the stimulated infiltration of the river water, followed by the subsurface flow in the sand and gravel layer at the bottom of the river bed. (3) in the early stage of pumping, the water output is mainly supplied by the static reserves of the sand bed of the filter bed, at which time the seepage field is greatly reduced. The depth of water level tends to be stable and extends to the bottom of the filter bed with the stimulation and recharge of the river water. (4) the intake pipe not only intakes water, but also stimulates the infiltration and recharge of the river, which leads to the formation of a low potential area near the intake pipe. No matter how large the amount of water is, the closer it is to the area of the water filter pipe, the larger the range of the depth of water head drop is and the larger the hydraulic gradient is, and the smaller the influence of water intake is, the smaller the hydraulic gradient is when the water is far away from the area of the water intake pipe. (5) five different mathematical analytical methods, including single well pumping method, large well, canal analogy, vertical infiltration coefficient method and radiating well formula replacement method, are used to calculate the water output of seepage field in laboratory simulation test. Due to the difference of hydrogeological parameters between different analytical formulas, there are different proportions between the calculated values of different analytical methods and the actual water output: the difference value of the analogy formula of seepage canal is the largest; The difference of single well pumping method, large well method and radiation well formula replacement method is the second, and the vertical infiltration coefficient method is the least. (6) by introducing the numerical simulation method, the water intake of Beipiao reverse percolation project is simulated and the project area model is established by using Visual Modflow software. The reliability of the model in Beipiao reverse percolation project is determined by discretization of model space, generalization of boundary, selection of hydrogeological parameters, design of model scheme and verification of basic model. On this basis, through the calculation of the water intake of Beipiao reverse percolation project under the condition of single chamber pumping and multi-chamber simultaneous pumping, the numerical simulation method is carried out. The numerical simulation method is widely used in the calculation of the water intake of leachate project, and the reliability of the calculation results is high.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV67

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