中文摘要：

弯曲河道中截流水流运动规律极为复杂,弯道边界形态和立堵截流布置方式的不同对截流难度均有很大的影响,对弯道中立堵截流龙口水力特性进行分析,有助于了解复杂的水流流态并选择合适的截流方案。本文考虑弯曲河道截流的主要影响因素,以施工水力学为基础,建立弯道截流龙口水流流态和堤头局部水力特性的计算模型,分析弯道相对河宽、弯道弯角和龙口位置对水深和流速变化的影响。分析结果表明弯道截流龙口流速变化有显著的时变差异和位变差异,并给出了龙口相对水深和堤头局部流速随弯道形态的变化关系。最后结合大渡河丹巴水电站河湾上截流的工程案例分析比较,验证了计算模型的可行性和分析结果的适用性,为河湾中截流方案及其截流施工布置型式的选择提供了理论依据。

英文摘要：

The water flow characteristics during the closure of curve river is extremely complex： both the curve shape of river and the layout of closure structures take great influences on the difficulty of river clo- sure. The study of the hydrodynamic characteristics in different layout modes will be useful in determining the appropriate plan for river closure. The main influencing factors for curve river closure were analyzed, and a calculation model for the flow regime of gap was built on the basis of construction hydraulics. The in- fluences of the width ratio of gap to river, the bend angle and the gap location on flow velocity were stud- ied. The differences of time-varying and place-varying for flow velocity in gap were put forward, and rela- tive water depth and flow velocity of gap with respect to the river bend were given by this model. Finally, the feasibility of the calculation model and the applicability of the conclusions had been verified by the curve river closure of Danba Hydropower Station construction. The study can be an important reference for the optimal design of river closure layout and scheme.