主河道岸坡角和支流汇入量对泥沙冲淤的影响

The Influence of the Bank Slope Angle and Tributary Inflow on Sediment Erosion and Deposition

为了分析常州城市河道淤积的机制,采用了量纲分析和水槽实验的方法,研究支流河道汇入主流河道过程中,主河道岸坡角、支流与主流的流量比、密度弗劳德数对汇流区冲刷的影响。研究将支流水槽与主流水槽的汇流角定为90°,采用不同的流量比和密度弗劳德数对四种不同岸坡角(45°、60°、75°、90°)进行对比实验。结果表明:支流河道中的流量与主流河道的流量比值越小时,岸坡角对冲刷深度的影响越大;对于任何给定的密度弗劳德数,越小的岸坡角可导致越小冲刷深度。依据拟合得到的两个经验关系式,岸坡角对泥沙淤积高度的影响大于对冲刷深度的影响;密度弗劳德数对无量纲冲刷深度影响最大,岸坡角对无量纲淤积高度的影响最大。

In order to analyze the mechanism of the siltation of urban river in Changzhou,this paper uses the method of dimensional analysis and water channel experiment to study the influence of bank slope angle,flow ratio and density Froude number on the scour of the confluence area during the process of tributary river flowing into the mainstream river. In this study,the confluence angle of tributary flume and mainstream flume is set at 90°,and four different bank slope angles(45°,60°,75°,90°)are compared with different flow ratios and density Froude numbers. The results show that the smaller the ratio of flow in tributary to the flow of the main stream,the greater the influence of the bank slope angle on scour depth is. For any given density Froude number,the smaller bank slope angle can lead to the smaller scour depth.According to the two empirical relations obtained by fitting,the influence of the bank slope angle on the height of sediment deposition is more than that on the scour depth,and the density Froude number has the greatest influence on dimensionless scour depth,and the bank slope angle has the greatest influence on the dimensionless sedimentation height.