新洋港闸下港道适宜断面与平衡流量

Study on appropriate section and balanced flow of channel downstream the Xinyanggang Sluice

在总结前人关于新洋港闸冲淤平衡流量研究成果的基础上,分析了自建闸至2012年新洋港闸下港道的冲淤情势和一般规律。基于2008—2012年港道冲淤和水情资料,采用相关性分析方法,重点分析了下泄径流对闸下港道的冲淤效果。结果表明：为了维持港道冲淤平衡,闸门不宜长期关闭,非汛期不排水天数占总天数的比例不宜高于42%；径流和潮流对水流输沙能力共同产生作用,径流条件可以改善港道内的涨落潮不平衡输沙现象；较弱的落潮流只能携带泥沙下泄7～9 km,长时间大流量开闸有利于港道稳定；当港道达到冲淤平衡时,日均下泄径流量Q与港道平均断面积A之间符合Q=0.13 A的定量关系；在目前港道形态下,港道健康运行的适宜断面积约为664 m^2,其冲淤平衡日均下泄径流量约为86 m^3/s。

This paper summarizes the research achievements on erosion-siltation balanced flow of Xinyanggang Sluice,and analyzes the erosion-siltation conditions and general laws of channel downstream sluice for 2012. Based on the data related to the erosion-siltation and water regime during the period from 2008 to 2012, the effects of discharging runoff on the erosion-siltation of the channel downstream the Xinyanggang Sluice are mainly analyzed with correlation analysis method. The results show that to keep the channel stable, the floodgate is not suitable to be closed for a long time and the ratio of undrained days accounting for total days should be less than 42% in non-flood season. Runoff and tides interact on sediment transport capacity of flow, and the unbalanced sediment transportation at flood and ebb tides in channel can be improved by runoff conditions. Sediment can only be carried 7 to 9 km seaward by weaker ebb currents, so large discharges for long time will be useful for stability of the channel. When the channel reaches the equilibrium state of erosion-siltation, there is a relationship between daily average discharge （ Q ） and the average cross-section area （ A ） of the channel （i. e. ,Q=0.13A）. In the present channel regime, for proper functioning of the channel, the area is approximately 664 m2 and the daily average discharge is approximately 86 m3/s.