桥梁工程跨堤布置与防洪影响研究

Location of Bridge-span across Levees and Its Effects on Flood Control

为了解桥梁工程跨堤布置对两岸防洪堤及河道防洪的影响,基于概化的数值渠道,采用MIKE21二维水流数学模型,分别从桥墩近堤距离、桥墩轴线布置及桥墩墩型设计三方面设定不同的河道参数及墩堤布置情况,模拟分析了近堤水流流速和墩堤间局部流场变化情况,揭示了不同情形下近堤流速及流场变化的规律,研究了其对河道防洪的影响。结果表明,桥梁跨堤、桥墩近岸布置时,增大近堤距离、减小桥墩轴线与河道岸线夹角和采用单一矩形壁式墩型均可减小对河道岸坡稳定及防洪安全的不利影响。

To study the location of bridge-span across levees and its effects on nearby levees and watercourses for flood prevention,the authors simulate relation of levees and bridges based on numerical channel by MIKE21 of two-dimensional flow model.Different parameters of watercourses are set with consideration to the aspects of distances between bridge piers and bank,pier-axis location and types of piers.Furthermore,flow velocity near bank and dynamic condition of flow between piers and bank are simulated.And then flow velocity near bank under various conditions and relevant changing regulations are revealed.Finally,the impact of flood control is studied.The results show that the adverse effect on bank stability and flood prevention can be reduced by increasing distance of piers from bank,reducing included angle between pier-axis and bank,replacement with unitary rectangle piers while arranging bridge-span and its location.