平原河网区河道交汊口分流特性模型试验研究

Model test study on diversion characteristics of river junction in plain river network area

以苏南运河-蠡河-望虞河交汊河道为研究对象,基于经验证的江苏省太湖地区整体一维河网数学模型及苏南运河-蠡河-望虞河交汊口局部物理模型,构建了交汊口平面二维数学模型,利用“16·7”超历史洪水资料并联合物理模型进行验证,在现状交汊角计算基础上,进一步模拟了苏南运河-蠡河变交汊角条件下蠡河分流比特性,并开展了多因素影响分析。结果表明,苏南运河-蠡河-望虞河分汊口不同于“Y”型或者斜接形交汊口,蠡河分流比主要由望虞河水位与苏南运河-望虞河水位差决定,与苏南运河下泄流量关系较小;苏南运河-蠡河交汊角度对蠡河分流比影响不大,主要是口门回流区束缩了支流有效过水宽度,导致进水口的实际过流宽度小于支流宽度。

This paper takes the South Jiangsu Canal-Li River-Wangyu River Interchange Channel as the research object,based on the verification of the overall one-dimensional river network mathematical model of Jiangsu Taihu area and the local physical model of the South Jiangsu Canal-Li River-Wangyu River intersection,a two-dimensional mathematical model of intersection is constructed.Based on the“16.7”exceeding-historical flood data,the combination of the physical model and the calculation of current intersection angle,the characteristics of the Li River diversion ratio under the conditions of the South Jiangsu Canal-Li River interchange angle are further simulated and multi-factor impact analyses are carried out.The results show that the junction of the South Jiangsu Canal-Li River-Wangyu River is different from the“Y”type or the slanting junction,and the water diversion ratio of the Li River is mainly due to the water level difference between the Wangyu River and the South Jiangsu Canal-Wangyu River,which has little relationship with the discharge flow of the South Jiangsu Canal.The influence of the intersection of the South Jiangsu Canal and the Li River on the diversion ratio of the Li River is not significant.It is mainly because the mouth recirculation zone shrinks the effective over-water width of the tributary,resulting in the actual width of the inlet smaller than the tributary width.