漫滩流量对河床演变及防洪航运的影响研究

Influence of bank-full discharge on riverbed erosion, flood control and navigation

我国一直遭受频繁洪水等灾害的威胁,大流量过后河流泥沙冲淤相对平衡被破坏,引起河床的再造床过程,发生河床演变,且若不加以控制可能会导致严重的洪灾,造成人民生命财产损失。利用全动床水槽模型,模拟复式河道的大流量作用及大流量作用后流量恢复对于河床演变的影响,在单次流量处理及大流量处理后施加平滩流量这两种处理方式下,分析全动床条件下复式河道河床演变对于河道行洪及通航能力的影响。结果表明:来流量大于平滩流量一定范围内,航深变化基本表现为随流量增大而降低。因此,从航深角度考虑,在高于平滩流量一定范围内,流量越大越不利于河道通航;大流量通过时,河道主槽床面被淤积。大流量通过恢复平滩流量作用后,主槽中下游河道宽度被束窄近一半,河道行洪能力大幅度减低,通航能力也有很大程度降低。

China has always been threatened by frequent floods and other disasters.After the flood,the relative balance of the river is destroyed.Flood may cause the river to rebuild the bed,lead to the evolution of the riverbed,and if the control is not in time,it will lead to serious loss of life and property.An experiment was conducted by compound fluvial channel with fully mobile bed to simulate the impact of large-flow flushing and flow recovery after large-flow flushing on riverbed evolution.On the conditions of a bank-full discharge after a single-flow and a bank-full discharge after large-flow,the influence of riverbed evolution on the river flooding and navigation capacity was as follows:within a certain range above the bank-full discharge,the variation of the depth of waterway was basically reduced as the flow increases.Therefore,considering the navigational capacity of the river from the depth of waterway,the greater the flow was,the more unfavorable the navigation was.When the large flow passes,the riverbed of the main channel was deposited.When the large-flow was restored to the bank-full discharge,the midstream and downstream of main channel would be narrowed by half,which would obviously affect the flooding capacity of the river.From the perspective of the depth of waterway,the navigation capacity of the river would be greatly reduced.