感潮河段横向泄洪冲刷和淤积特性试验研究

Experimental Study on Scouring and Silting Characteristics of Lateral Flood Discharge in Tidal Reach

为研究横向直排泄洪对感潮河段局部冲刷和淤积问题,以闽江魁岐泄洪枢纽工程为例,通过大比尺水力模型试验,分别设计了不同河道径流、泄洪历时及涨落潮等试验工况,观测了不同试验工况下的河床冲淤特性。结果表明,短历时泄洪落潮工况冲坑深度较涨潮工况增加约35%,长历时泄洪涨落潮工况冲坑深度相差约4%;受涨潮顶托作用,涨潮工况下河床冲刷面积更为集中。不同涨落潮泄洪工况条件下,河床冲刷深度对冲刷历时尤为敏感;河床淤积超过一定高度时,对河道流量、冲刷历时和涨落潮工况敏感度不高。受涨落潮影响,河床冲淤方向往复摆动,河床防冲刷措施应向泄洪出口上下游位置合理延伸。

In order to study the local scour and siltation of tidal reach caused by transverse direct discharge flood discharge,taking the Kuiqi flood discharge project of Minjiang River as an example,different river runoff,flood discharge duration,fluctuation tide and other test conditions were designed through large-scale hydraulic model test.And then the scour and siltation characteristics of river bed were observed under different test conditions.The results show that the scour depth of short duration flood discharge and ebb tide condition is about 35%higher than that of flood tide condition,and the scour depth difference of long duration flood discharge and ebb tide condition is about 4%;The scour area of riverbed is more concentrated under flood tide condition due to the support of flood tide.Under different flood discharge conditions,the riverbed scouring depth is particularly sensitive to scouring duration.When the riverbed siltation exceeds a certain height,the sensitivity to river flow,scouring duration and flood tide and ebb tide conditions is not high.Under the impact of rising tide and falling tide,the scouring and silting direction of the river bed swings back and forth,and the anti-scouring measures of the river bed should be extended to the upstream and downstream of the flood discharge outlet.