As a research focus for ice-involved open channel projects,the roughness of ice cover is a fundamental parameter for determining the relationship between water level and discharge in open channels during freezing peri-od.Given the current lack of data on ice sheet roughness in large-scale concrete channels,we investigated the channel section between Tanghe sluice gate and Fangshui sluice gate of the Middle Route of the South-to-North Wa-ter Diversion Project in the north of Shijiazhuang as a case study.Utilizing daily measured data of water level and flow rate from January to February 2016,we employed the Bernoulli energy equation and the Xie Cai-Manning for-mula to estimate channel roughness and analyze the changes in roughness before and after freezing,both qualitative-ly and quantitatively.The results are as follows:1)The roughness coefficient nb of the studied channel during free-flow period is 0.016 7.The average comprehensive roughness nc of the ice sheet during freezing period is 0.014 6,and the average surface roughness ni beneath the ice sheet is 0.011 8.2)Due to hydraulic abrasion,the roughness of ice sheet decreases over time during freezing.3)Once ice sheet is formed in the channel,the water delivery ca-pacity significantly diminishes,achieving only 66.7％of the designed flow rate.These findings provide a scientific basis for optimizing water transportation scheduling and designing similar engineering projects during freezing period.
关键词
南水北调中线工程/冰盖糙率/渠道糙率/输水能力/水头损失
Key words
South-to-North Water Diversion Middle Route Project/ice cover roughness/channel roughness/water transfer capacity/head loss
维普
万方数据