合流制管道沉积物冲刷模型试验研究

发布时间：2018-04-02 07:33

本文选题：合流制管道　切入点：沉积物　出处：《武汉理工大学》2013年硕士论文

【摘要】：随着我国现代化建设步伐的加快,城市排水系统造成的环境问题逐渐显现。目前我国许多老城区仍然沿用截留式合流制排水系统,晴天合流制管道中流量和流速较小,大量的可沉污染物沉入管道底部,当雨天管道中流量增大时,管底沉积物被冲刷释放出来,致使合流制排水系统雨天溢流污染严重。为了探究雨天管底沉积物冲刷释放对溢流水质的影响,本文进行了管底沉积物冲刷模型的试验研究,主要结论如下： (1)通过实地采样分析合流制管底沉积物的物理化学特性,表明沉积物中N、P的含量分别为2229.4mg/kg沉积物、885.1mg/kg沉积物,且主要以悬浮物的形式存在。 (2)冲刷试验结果表明,沉积物的释放规律大致可以分为四类：指数衰减冲刷、单峰冲刷、多峰冲刷、复杂冲刷。影响沉积物冲刷效果的主要因素有流量、沉积物量、沉积物涂抹湿周长度、沉积物粒径及含水率。 (3)采用SWMM中管道沉积物排放模型对管道冲刷出水结果的模拟表明,该模型进行管道出水模拟具有可行性,拟合度高于70%,但是模型中参数幻差别较大,其直接受初期出水浓度大小的影响,幻受冲刷过程的影响,冲刷现象越接近于指数衰减,模型拟合度就越高,参数k2绝对值就越大。 (4)利用模型公式W=C3BGC4对管道冲刷出水中沉积物量进行拟合,得到污染物指标COD、TN、TP的参数C3值分别为0.013、0.011、0.012,C4为1。并且模型计算结果与实际冲刷具有较高的拟合度。
[Abstract]:With the acceleration of the pace of modernization in China, the environmental problems caused by the urban drainage system are gradually emerging. At present, many old urban areas in China still use the interception combined flow drainage system, and the flow rate and velocity of the pipeline are relatively small in sunny days. A large number of precipitable pollutants sink into the bottom of the pipe, and when the flow in the pipe increases on rainy days, the sediment from the bottom of the pipe is washed out and released. In order to investigate the effect of sediment scour and release on the overflow water quality, the model of pipe bottom sediment scour is studied in this paper. The main conclusions are as follows:. 1) the physical and chemical characteristics of the sediment in the bottom of the confluence pipe are analyzed by field sampling. The results show that the content of NNP in the sediment is 885.1 mg / kg of 2229.4mg/kg sediment, and it mainly exists in the form of suspended solids. 2) the results of scour test show that the sediment release law can be divided into four categories: exponential attenuation scour, single peak scour, multi-peak scour, complex scour. Length of wet cycle, grain size and moisture content of sediment smear. 3) the simulation results of pipe erosion effluent with SWMM model show that the model is feasible, and the fitting degree is higher than 70, but the parameters of the model differ greatly. It is directly affected by the initial effluent concentration, and the illusion is affected by the scour process. The closer the scour is to the exponential attenuation, the higher the model fitting degree is and the absolute value of the parameter K2 is larger. (4) the model formula W=C3BGC4 is used to fit the sediment quantity in the scour water of pipeline, and the parameter C _ 3 of pollutant index CODN _ N _ (TP) is 0.013 ~ 0.011 ~ (0.011) ~ 0.012 ~ (4) C ~ (4), respectively. The result of the model has a high fitting with the actual scour.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU992

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