双层挡潮闸水力冲淤试验研究

Experimental Research on the Hydraulic Erosion and Siltation of the Double-layer Tide Gate

挡潮闸下易形成大范围淤积,其冲淤效果直接影响工程效益的发挥。双层挡潮闸作为一种新型闸门形式已在浙江多个工程中应用,但尚未系统研究其冲淤效果。结合某大型泵站出口挡潮闸工程,建立1∶25冲淤物理模型,并以冲淤效果和冲淤效率为指标,对闸门不同运行方式的水力冲淤特性进行研究。研究表明:挡潮闸下的口门淤积1~2 m范围内,可通过运行一台泵站机组(20 m^(3)/s)开启上层闸门进行水力冲淤解决,不同工况的闸下有效冲淤时间均较短,冲沟稳定时间一般在15 min以内。闸下水位越低越有利于冲淤,开启一孔闸门运行,水流较为集中,在10 min内可将闸下护坦冲开;开启二孔闸门运行,出闸单宽流量降低50%,在初期可有效冲淤,且效率较高,但不能将护坦全部冲开,冲淤效果不能完全满足。当闸下淤积较高,冲沙效率相对较高。双层挡潮闸具有较好地冲淤效率及效果,相关成果可供设计及运行管理参考。

It is easy to form large-scale sedimentation under the tide gate,which may have a serious impact on the operation of the project.As a new type of gate,the double-layer tide gate has been applied to many projects in Zhejiang Province,but its scouring and silting effect has not been systematically studied.Combined with the tidal gate project at the outlet of a large pump station,a 1∶25 physical model is established,and the hydraulic scouring and silting characteristics of different gates are studied with the scouring and silting effect and scouring and silting efficiency as indicators.The research shows that the hydraulic scouring and silting can be solved by running a pump station unit(20 m^(3)/s)and opening the upper gate within the range of 1~2 m.The effective scouring and silting time under the gate under different working conditions is short,and gully stability time is generally less than 15 min.The lower the water level under the gate,the more favorable it is for sand flushing.Open the one-hole gate for operation,and the scouring and silting flow is relatively concentrated.The apron under the gate can be flushed out within 10 min.If the two-hole gate is opened for operation,the discharge per unit width of the gate can be reduced,which can effectively scour and silt in the initial stage,with high efficiency,but the apron cannot be flushed out completely,and the scouring and silting effect cannot be fully met.When the sedimentation under the sluice is high and the sediment is abundant,the flushing efficiency is relatively high.The double-layer tide gate has good scouring and silting efficiency and effect.The relevant results can be used as a reference for design and operation management.