雨水管道沉积物冲刷特性
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摘要
通过试验模拟雨水管道内沉积物的冲刷过程,探索不同水力、沉积物条件下雨水管道内的冲刷规律,结合数学模型拟合,计算特定条件下管道内沉积物的冲刷率和冲刷通量。结果表明,不同条件对管道内沉积物冲刷过程有较大影响,管道内较大的流量、坡度下,水流动能大,冲刷能力强,会带来较高的冲刷通量;而较小的粒径表层易剥离,以悬浮的形式被水流冲刷带走,因此在冲刷的前15 s表现出更高的冲刷通量;沉积厚度较大时,管道末端出水悬浮颗粒物质量浓度较高,也易形成较大的冲刷通量。经过构建数学模型,计算出了特定条件下雨水管道沉积物的冲刷率和冲刷通量。
The paper is inclined to present an analysis of the scouring features of the sedimental left-over elements in the rainwater pipe scouring process of the sediment in such pipes through a simulation research. For the above said research purpose,we have proposed the calculation method of the macroscopic parameters of the scouring process in accordance with the mathematical models and calculated the scouring rate and flux of the sediment.The results of the calculation show that different conditions can have a great effect on the scouring process in the pipe. The actual situation should be that: the higher the flow or the slope has,the greater energy of the water current may produce and in turn stronger capability and higher scouring flux the scouring may be endowed with. For example,in the first 15 s of the scouring,a larger slope can result in a larger scouring flux. However,15 seconds later,the reverse would be true. Analyzing the trend of the scouring rate can let us know that,if the flow rate or the slope degree is large enough or the scouring time is long enough,it would be possible for the scouring rate to reach 100%. On the other hand, smaller particles can be easily peeled off and scoured away by the water flow in the form of suspension. Its starting process can just demand a little shear stress,which implies a higher scouring flux in the first 15 s of the scouring.However,when the sedimentary thickness is greater,the concentration of the suspended particles in the effluent of the pipe should be higher,which also tends to result in a greater scouring flux. Under the different conditions,the difference in the concentration of the suspended particles in the effluent can mainly appear in the initial 30 s of the scouring,with the concentration being closer 120 s later. Hence,the scouring flux under different conditions can help us to deduce the following regulation: that is,it tends to decrease exponentially with the time lasting,and eventually tends to become horizontal. But,in the initial 30 s of the process,the scouring flux tends to decrease most significantly. Therefore,it would be possible for the scouring rate and the flux of the sediment to be calculated and worked out in the rainwater pipe under certain condition by using the mathematical models of the scouring process.
The paper is inclined to present an analysis of the scouring features of the sedimental left-over elements in the rainwater pipe scouring process of the sediment in such pipes through a simulation research. For the above said research purpose,we have proposed the calculation method of the macroscopic parameters of the scouring process in accordance with the mathematical models and calculated the scouring rate and flux of the sediment.The results of the calculation show that different conditions can have a great effect on the scouring process in the pipe. The actual situation should be that: the higher the flow or the slope has,the greater energy of the water current may produce and in turn stronger capability and higher scouring flux the scouring may be endowed with. For example,in the first 15 s of the scouring,a larger slope can result in a larger scouring flux. However,15 seconds later,the reverse would be true. Analyzing the trend of the scouring rate can let us know that,if the flow rate or the slope degree is large enough or the scouring time is long enough,it would be possible for the scouring rate to reach 100%. On the other hand, smaller particles can be easily peeled off and scoured away by the water flow in the form of suspension. Its starting process can just demand a little shear stress,which implies a higher scouring flux in the first 15 s of the scouring.However,when the sedimentary thickness is greater,the concentration of the suspended particles in the effluent of the pipe should be higher,which also tends to result in a greater scouring flux. Under the different conditions,the difference in the concentration of the suspended particles in the effluent can mainly appear in the initial 30 s of the scouring,with the concentration being closer 120 s later. Hence,the scouring flux under different conditions can help us to deduce the following regulation: that is,it tends to decrease exponentially with the time lasting,and eventually tends to become horizontal. But,in the initial 30 s of the process,the scouring flux tends to decrease most significantly. Therefore,it would be possible for the scouring rate and the flux of the sediment to be calculated and worked out in the rainwater pipe under certain condition by using the mathematical models of the scouring process.
引文
[1] SANG Langtao(桑浪涛),SHI Xuan(石烜),ZHANG Tong(张彤),et al. Law of pollutant erosion and deposition in urban sewage network[J]. Environmental Science(环境科学),2017,38(5):1965-1971.
[2] ZHANG Wei(张伟),YU Jian(余健),LI Wei(李葳),et al. Research and analysis on deposition status of drainage pipes in Guangzhou City[J]. Water&Wastewater Engineering(给水排水),2012,38(7):147-150.
[3] LI Haiyan(李海燕),MEI Huirui(梅慧瑞),XU Boping(徐波平). Investigation and analysis of storm sewer sediments in Beijing[J]. China Water and Wastewater(中国给水排水),2011,27(6):36-39.
[4] BUTLER D,MAY R,ACKERS J. Self-cleansing sewer design based on sediment transport principles[J]. Journal of Hydraulic Engineering,2003,129(4):276-282.
[5] CHUAI Xiaoming(揣小明),YANG Liuyan(杨柳燕),CHENG Shubo(程书波),et al. Characteristics and influencing factors of phosphorus adsorption on sediment in Lake Taihu and Lake Hulun[J]. Environmental Science(环境科学),2014,35(3):951-957.
[6] LU Shaoyong(卢少勇),YUAN Ye(远野),JIN Xiangcan(金相灿),et al. Speciation distribution of nitrogen in sediments of 7 rivers around Taihu Lake[J]. Environmental Science(环境科学),2012,33(5):1497-1502.
[7] GAO Yuan(高原),WANG Hongwu(王红武),ZHNAG Shanfa(张善发),et al. Current research progress in combined sewer sediments and their modles[J]. China Water and Wastewater(中国给水排水),2010,26(2):15-18.
[8] GHANI A A. Sediment transport in sewers[D]. Newcastle:Newcastle University,1993.
[9] GUO Q,FAN C Y,RAGHAVEN R,et al. Gate and vacuum flushing of sewer sediment:laboratory testing[J].Journal of Hydraulic Engineering, 2004, 130(5):463-466.
[10] VONGVISESSOMJAI N,TINGSANCHALI T,BABEL M S. Non-deposition design criteria for sewers with part-full flow[J]. Urban Water Journal,2010,7(1):61-77.
[11] OTA J J,PERRUSQUIA G S. Particle velocity and sediment transport at the limit of deposition in sewers[J].Water Science&Technology,2013,67(5):959-967.
[12] JIN Pengkang(金鹏康),BIAN Xiaozheng(卞晓峥),JIAO Ding(焦丁),et al. On the pollutant deposition and erosion release in the urban sewer networks[J].Journal of Safety and Environment(安全与环境学报),2016,16(5):253-257.
[13] BERSINGER T,LE H I,BAREILLE G,et al. Assessment of erosion and sedimentation dynamic in a combined sewer network using online turbidity monitoring[J]. Water Science&Technology,2015,72(8):1375-1382.
[14] SHAHSAVARI G,ARNAUD-FASSETTA G,CAMPISANO A. A field experiment to evaluate the cleaning performance of sewer flushing on non-uniform sediment deposits[J]. Water Research,2017,118:59-69.
[15] CARNACINA I,LARRARTE F,LEONARDI N. Acoustic measurement and morphological features of organic sediment deposits in combined sewer networks[J]. Water Research,2017,112:279-290.
[16] BERTRANDKRAJEWSKI J L,BARDIN J P,GIBELLO C. Long term monitoring of sewer sediment accumulation and flushing experiments in a man-entry sewer[J]. Water Science&Technology,2006,54(6/7):109-117.
[17] SCHELLART A N,BUIJS F A,TAIT S J,et al. Estimation of uncertainty in long term combined sewer sediment behaviour predictions,a UK case study[J]. Water Science&Technology,2008,57(9):1405-1411.
[18] WALSKI T,EDWARDS B,HELFER E,et al. Transport of large solids in sewer pipes[J]. Water Environment Research,2009,81(7):709-714.
[19] XU Shangling(徐尚玲). Researching on pollution load of overflow in combined drainage channels in runoff scouring(城市排水管道沉积物径流冲刷污染效应的研究)[D]. Beijing:Beijing University of Civil Engineering and Architecture,2013:50-51.
[20] EBTEHAJ I,BONAKDARI H,SHAMSHIRBAND S,et al. New approach to estimate velocity at limit of deposition in storm sewers using vector machine coupled with firefly algorithm[J]. Journal of Pipeline Systems Engineering&Practice,2017,8(2):04016018.
[21] BONG C H J,LAU T L,GHANI A A,et al. Sediment deposit thickness and its effect on critical velocity for incipient motion[J]. Water Science&Technology,2016,74(8):1876-1884.
[22] MA Meijing(马美景),WANG Junguang(王军光),GUO Zhonglu(郭忠录),et al. Research on sediment and solute transport on red soil slope under simultaneous influence of scouring flow[J]. Acta Pedologica Sinica(土壤学报),2016,53(2):365-374.
[23] GENG Lixin(耿立馨). Study on flush modle of sediment in combined sewer(合流制管道沉积物冲刷模型试验研究)[D]. Wuhan:Wuhan University of Technology,2013.
[24] JIANG Lei(蒋磊). Experimental study on scour and transport of cohesive sediment after deposition and consolidation(淤积固结后粘性泥沙冲刷运动规律试验研究)[D]. Wuhan:Wuhan University,2012.
[25] BLACK K S,TOLHURST T J,PATERSON D M,et al.Working with natural cohesive sediments[J]. Journal of Hydraulic Engineering,2002,128(1):2-8.
[26] WANG Zhiwei(王志伟),CHEN Zhicheng(陈志成),AI Zhao(艾钊),et al. Erosion and desertification with Mountain Yimeng typical surface soil caused by different rainfall intensity and slope[J]. Journal of Soil and Water Conservation(水土保持学报),2012,26(6):17-20.
[27] CHENG Q,MA W,CAI Q. The relative importance of soil crust and slope angle in runoff and soil loss:a case study in the hilly areas of the Loess Plateau,North China[J]. Geojournal,2008,71(2/3):117-125.
[28] MA Yan(马妍). Study on erosion characteristics and transport principles of sewer sediment in sewerage system(排水系统管内沉积物的冲蚀输移特性与规律研究)[D]. Hangzhou:Zhejiang University,2014.
[29] AHYERRE M,CHEBBO G,SAAD M. Sources and erosion of organic solids in a combined sewer[J]. Urban Water,2000,2(4):305-315.
[30] CHEN Jinjun(陈进军). Characteristics of sediment grain size and the influence factors in alluvial rivers-a case study from the north piedmont of the Qilian Shan(冲积河流沉积物粒径的变化特征及其影响因素分析-以祁连山北麓为例)[D]. Lanzhou:Lanzhou University,2017.
[2] ZHANG Wei(张伟),YU Jian(余健),LI Wei(李葳),et al. Research and analysis on deposition status of drainage pipes in Guangzhou City[J]. Water&Wastewater Engineering(给水排水),2012,38(7):147-150.
[3] LI Haiyan(李海燕),MEI Huirui(梅慧瑞),XU Boping(徐波平). Investigation and analysis of storm sewer sediments in Beijing[J]. China Water and Wastewater(中国给水排水),2011,27(6):36-39.
[4] BUTLER D,MAY R,ACKERS J. Self-cleansing sewer design based on sediment transport principles[J]. Journal of Hydraulic Engineering,2003,129(4):276-282.
[5] CHUAI Xiaoming(揣小明),YANG Liuyan(杨柳燕),CHENG Shubo(程书波),et al. Characteristics and influencing factors of phosphorus adsorption on sediment in Lake Taihu and Lake Hulun[J]. Environmental Science(环境科学),2014,35(3):951-957.
[6] LU Shaoyong(卢少勇),YUAN Ye(远野),JIN Xiangcan(金相灿),et al. Speciation distribution of nitrogen in sediments of 7 rivers around Taihu Lake[J]. Environmental Science(环境科学),2012,33(5):1497-1502.
[7] GAO Yuan(高原),WANG Hongwu(王红武),ZHNAG Shanfa(张善发),et al. Current research progress in combined sewer sediments and their modles[J]. China Water and Wastewater(中国给水排水),2010,26(2):15-18.
[8] GHANI A A. Sediment transport in sewers[D]. Newcastle:Newcastle University,1993.
[9] GUO Q,FAN C Y,RAGHAVEN R,et al. Gate and vacuum flushing of sewer sediment:laboratory testing[J].Journal of Hydraulic Engineering, 2004, 130(5):463-466.
[10] VONGVISESSOMJAI N,TINGSANCHALI T,BABEL M S. Non-deposition design criteria for sewers with part-full flow[J]. Urban Water Journal,2010,7(1):61-77.
[11] OTA J J,PERRUSQUIA G S. Particle velocity and sediment transport at the limit of deposition in sewers[J].Water Science&Technology,2013,67(5):959-967.
[12] JIN Pengkang(金鹏康),BIAN Xiaozheng(卞晓峥),JIAO Ding(焦丁),et al. On the pollutant deposition and erosion release in the urban sewer networks[J].Journal of Safety and Environment(安全与环境学报),2016,16(5):253-257.
[13] BERSINGER T,LE H I,BAREILLE G,et al. Assessment of erosion and sedimentation dynamic in a combined sewer network using online turbidity monitoring[J]. Water Science&Technology,2015,72(8):1375-1382.
[14] SHAHSAVARI G,ARNAUD-FASSETTA G,CAMPISANO A. A field experiment to evaluate the cleaning performance of sewer flushing on non-uniform sediment deposits[J]. Water Research,2017,118:59-69.
[15] CARNACINA I,LARRARTE F,LEONARDI N. Acoustic measurement and morphological features of organic sediment deposits in combined sewer networks[J]. Water Research,2017,112:279-290.
[16] BERTRANDKRAJEWSKI J L,BARDIN J P,GIBELLO C. Long term monitoring of sewer sediment accumulation and flushing experiments in a man-entry sewer[J]. Water Science&Technology,2006,54(6/7):109-117.
[17] SCHELLART A N,BUIJS F A,TAIT S J,et al. Estimation of uncertainty in long term combined sewer sediment behaviour predictions,a UK case study[J]. Water Science&Technology,2008,57(9):1405-1411.
[18] WALSKI T,EDWARDS B,HELFER E,et al. Transport of large solids in sewer pipes[J]. Water Environment Research,2009,81(7):709-714.
[19] XU Shangling(徐尚玲). Researching on pollution load of overflow in combined drainage channels in runoff scouring(城市排水管道沉积物径流冲刷污染效应的研究)[D]. Beijing:Beijing University of Civil Engineering and Architecture,2013:50-51.
[20] EBTEHAJ I,BONAKDARI H,SHAMSHIRBAND S,et al. New approach to estimate velocity at limit of deposition in storm sewers using vector machine coupled with firefly algorithm[J]. Journal of Pipeline Systems Engineering&Practice,2017,8(2):04016018.
[21] BONG C H J,LAU T L,GHANI A A,et al. Sediment deposit thickness and its effect on critical velocity for incipient motion[J]. Water Science&Technology,2016,74(8):1876-1884.
[22] MA Meijing(马美景),WANG Junguang(王军光),GUO Zhonglu(郭忠录),et al. Research on sediment and solute transport on red soil slope under simultaneous influence of scouring flow[J]. Acta Pedologica Sinica(土壤学报),2016,53(2):365-374.
[23] GENG Lixin(耿立馨). Study on flush modle of sediment in combined sewer(合流制管道沉积物冲刷模型试验研究)[D]. Wuhan:Wuhan University of Technology,2013.
[24] JIANG Lei(蒋磊). Experimental study on scour and transport of cohesive sediment after deposition and consolidation(淤积固结后粘性泥沙冲刷运动规律试验研究)[D]. Wuhan:Wuhan University,2012.
[25] BLACK K S,TOLHURST T J,PATERSON D M,et al.Working with natural cohesive sediments[J]. Journal of Hydraulic Engineering,2002,128(1):2-8.
[26] WANG Zhiwei(王志伟),CHEN Zhicheng(陈志成),AI Zhao(艾钊),et al. Erosion and desertification with Mountain Yimeng typical surface soil caused by different rainfall intensity and slope[J]. Journal of Soil and Water Conservation(水土保持学报),2012,26(6):17-20.
[27] CHENG Q,MA W,CAI Q. The relative importance of soil crust and slope angle in runoff and soil loss:a case study in the hilly areas of the Loess Plateau,North China[J]. Geojournal,2008,71(2/3):117-125.
[28] MA Yan(马妍). Study on erosion characteristics and transport principles of sewer sediment in sewerage system(排水系统管内沉积物的冲蚀输移特性与规律研究)[D]. Hangzhou:Zhejiang University,2014.
[29] AHYERRE M,CHEBBO G,SAAD M. Sources and erosion of organic solids in a combined sewer[J]. Urban Water,2000,2(4):305-315.
[30] CHEN Jinjun(陈进军). Characteristics of sediment grain size and the influence factors in alluvial rivers-a case study from the north piedmont of the Qilian Shan(冲积河流沉积物粒径的变化特征及其影响因素分析-以祁连山北麓为例)[D]. Lanzhou:Lanzhou University,2017.