长江扬中河段河势演变及治理研究

为进一步稳定长江中下游扬中河段的河势,归纳分析了新水沙条件下段内江心洲的历史治理情况,发现洲头崩坍后退、沿程阻力的减小等问题仍然存在。在现有河势控制工程的基础上,提出太平洲“裹头”及两缘护岸、落成洲右缘护岸和禄安洲“裹头”及两缘护岸的合理治理方案,模拟了治理方案实施前后的流量流速,分析了各治理方案下的治理效果。首先,太平洲近岸流速减小幅度在 0.01～0.05 m/s 之间,汊道分流基本无变化;其次,落成洲近岸流速均减小 0.02～0.04 m/s,对于该部位岸线的坍塌起到有效的控制作用;最后,禄安洲近岸流速总体减小 0.01～0.04 m/s,有利于洲头以及左右侧汊道分流的稳定。结果表明,所提出的治理方案能够有效降低区域内近岸流量及流速,有利于洲滩及汊道分流的稳定,对遏制岸线崩退和坍塌有至关重要的作用,以期为长江中下游江心洲的治理提供参考。

Analysis on river channel evolution and regulation of Yangzhong reach of Yangtze River

In order to further stabilize the river regime of Yangzhong River of Yangtze River, the historical management of cen- tral bar in the section under new water and sediment conditions was summarized and analyzed, and it was found that the prob- lems of head collapse and retreat of central bar and reduction of resistance along the course still exist. On the basis of the exist- ing river potential control project, reasonable treatment schemes were proposed for the "head" and two edge banks of Taip- ingzhou, the right edge bank of Luochengzhou and the "head" and two edge banks of Lu''anzhou, and the flow rates before and after the implementation of the treatment schemes were simulated and the treatment effects of each treatment scheme were ana- lyzed. The effect of treatment under each treatment scheme was analyzed. Firstly, the near-shore flow velocity of Taipingzhou was reduced in the range of 0.01-0.05 m/s, and there was no change in the branch diversions; secondly, the near-shore flow ve- locity of Luochengzhou was reduced by 0.02-0.04 m/s, which played an effective role in controlling the collapse of the shoreline in this area; finally, the near-shore flow velocity of Lu''anzhou was reduced by 0.01-0.04 m/s, which was generally beneficial to the head of the island and the branch diversions on the left and right sides stability. The results show that the proposed treatment scheme can effectively reduce the nearshore flow and velocity in the region, which is conducive to the stability of the continental beach and branching channel diversions, and is crucial to the containment of bank recession and collapse, with a view to provid- ing a reference for the treatment of the middle bar in the middle and lower reaches of the Yangtze River.