鄂北地区水资源配置工程夹河套段倒虹吸防护研究

Physical Model Test and Numerical Simulation on the Inverted Siphon Protection in River Confluence Reaches of North Hubei Water Transfer Project

针对鄂北地区水资源配置工程的唐白河夹河套段倒虹吸工程防护问题,建立了唐河、白河一维及夹河套区域二维水动力学耦合模型,综合考虑溃堤和漫堤等多种极端不利因素,计算分析了不同设计洪水标准下唐河和白河堤防溃决、漫溢等条件下的洪水影响范围及程度。选择最不利方案进行了无防护和有防护等不同情况下的物理模型冲刷试验,研究溃漫堤洪水对工程线路的冲刷影响。数学模型计算成果表明:溃堤洪水大流速主要分布在溃口附近区域,溃口位于工程线路附近时对工程的冲刷影响较严重。综合数学模型计算和物理模型试验结果,根据格栅石笼的冲刷变形程度及范围、冲刷坑范围及抗冲流速影响范围,确定了工程沿线不同的防护等级与范围,为夹河套倒虹吸工程防护方案设计提供支撑和依据。

The protection project of inverted siphon in the confluence reach of Tangbai River of North Hubei Water Transfer Project is studied in this paper.A hydrodynamic model coupling 1D model of Tanghe River and Baihe River and 2D model of Jiahetao reach was established for this protection problem.In consideration of various extreme unfavorable factors,e.g.,dike breaches and dike flooding,the range and degree of flooding impact under different design flood standards were calculated and analyzed.Meanwhile,the impacts of dike breaching and overbank flooding on project route were examined by physical model test under the most unfavorable condition in the presence and in the absence of protection.Numerical simulation results indicated that large flooding velocity was mainly found in the adjacent of breach,where severe scour will be induced at adjoining project route.Moreover,different protection levels and ranges were determined according to the deformation of grille-cage with gravels and the range of scour pit and erosion-resistance flow rate obtained from numerical simulation and erosion experiment.The research results offer support and basis for the design of protection scheme for the inverted siphon protection project in this study.