长江口为海陆双向河口,其南支受洪潮共同影响,河道演变较为复杂.在分析南支河段河道演变特征的基础上,通过建立长江口南支河段河工模型,重点开展了南支演变趋势预测研究.河演分析表明:20世纪60年代之后,徐六泾人工节点基本形成,上游河势变化对南支河床演变的影响明显减弱,南支河段江岸基本稳定,滩槽位置相对稳定.定床模型试验结果表明:模拟河段最大涨急流速为2.26 m/s,最大落急流速为2.69 m/s.动床模型试验结果表明:2016～2020年(循环4次)+100 a 一遇水沙年+300 a 一遇水沙年试验条件作用后,典型断面最深点相对冲深约7.8 m.研究成果可为类似河段演变分析提供参考.
Research on evolution characteristics and trend prediction of Yangtze River Estuary South Branch
The Yangtze River Estuary is a two-way estuary of land and sea.The South Branch is influenced by tidal floods,so the river channel evolution is relatively complicated.Based on the analysis of the river channel evolution char-acteristics in the South Branch section,through the establishment of a hydraulic model for the section,we predicted the evolutionary trends of the South Branch.The analysis of river channel evolution revealed that after the 1960s,the artificial node at Xuliujing was basically formed,the impact of upstream river regime changes on the riverbed evolution of the South Branch was significantly weakened,the riverbanks in the South Branch section were basically stable,with the posi-tions of shoals and channels exhibiting relative stability.The outcomes of the fixed-bed model test indicated that the maximum velocity at flood tide in the simulated river section was 2.26 m/s,and the maximum velocity at ebb tide was 2.69 m/s.The findings from the moving bed model test disclosed that following the test conditions of 2016 to 2020(four cycles)+once-in-a-century flow and sediment year+once-in-a-300 flow and sediment year,the relative scour depth of the deepest point of the typical section was approximately 7.8 m.The research results can provide a refer-ence for the evolution analysis of similar river reach.
river channel evolutionriver engineering modelYangtze River EstuarySouth Branch
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