河道改造对弯曲河段的水力影响模拟研究

以浏阳河朝正垸急弯河段为例 ,采用MIKE21水动力平面二维水流 -泥沙模型先进行率定 ,综合考虑长沙枢纽运行后湘江水位抬升对浏阳河下游的顶托与浏阳河不同频率洪水的叠加作用 ,采用该模型对上游直线段、弯段、下游直线段的水文变化、流速变化及冲淤情势进行多工况模拟.结果表明 :对于弯曲河道尽管改造拓宽弯曲段 ,在凸岸水流流速增大 ,可能存在冲刷 ,凹岸局部会产生淤积 ,在近邻弯曲下游段凹岸局部还会产生水位壅高.结果可指导本河段防洪规划设计 ,对类似工程也具有借鉴意义.

Simulation of the Hydraulic Impacts of the River Channel Regulation on the To rtuous River Channel

In this paper the section of Liuyang River in Chaozheng embankment was chosen as an example ,MIKE21 model was adopted which is able to solve plane 2D flow-sand mathematical model .The parameters were calibrated first , real world situation was considered thoroughly ,such as the development of Changsha junction and the Xiang River water level raise afterwards ,which will block Liuyang River ,as well as the superposition of different frequencies of floods . Many operation situations were also considered to simulate the changes in hydrological regime ,flow velocity and erosion and deposition balance at straight section in the upstream ,tortuous section ,and straight section in the downstream ,The results showed that for tortuous river channels the regulation will increase the flow velocity at concave bank where erosion and deposition at convex bank will happen and water level rising because of block in the downstream .This research is valuable to practice and similar projects .