【摘要】 汊道兴衰、洲滩的演变与其水沙输移特性密切相关。以沙市典型分汊浅滩河段为例,从河段水沙输移特性出发,结合水流泥沙、河道地形等实测资料,分析其河床演变特点,并根据三峡建库后水沙条件变化的特点利用数学模型预测了该河段的汊道和洲滩发展趋势。研究表明:所建模型能够准确地模拟该河段的水沙输移特性及洲滩的演变规律,因而具有较好的预测功能,三峡水库蓄水后河段洲滩动态变化结果与实测结果较吻合,这对三峡水库蓄水运用后其它分汊浅滩河段的研究具有借鉴意义。更多还原

【Abstract】 The rise and decline of braided reach and the fluvial process of continent and shoal are closely related to the characteristics of hydraulic and sediment transport.The paper focuses on the Shashi reach,a typical multi-branched meandering reach in the middle Yangtze River.Firstly,based on a large amount of field data,the evolution feature of this reach is analyzed in natural condition.Then,according to the effect of Three Gorge Project(TGP) on flow and sediment process,the trend of geomorphology change is predicted.Finally,based on the analysis above and the change character of flow & sediment,a depth-averaged 2-D flow and sediment numerical model is developed and applied to predict the further details of possible adjustments due to flow and sediment regulation after the TGP impoundment for 20 years.The results show that the fluvial process in the reach is closely related to the characteristics of flow and sediment transportation.The numerical model can simulate the characteristics of flow & sediment transportation and the rule of bars movement well.The prediction result is reasonable.The information provided in the paper is practical and helpful in the research on other multi-branched meandering reach in the middle Yangtze River after Three Gorges Reservoir impoundment.更多还原