建桥对长江中下游不同特性河段的水流运动影响

Influence of bridge construction on water movement in middle and lower reaches of Yangtze River

基于边界拟合良好的曲线网格上建立的平面二维水流运动数学模型,以长江中下游不同河段为例,针对不同特性河段,系统地分析了桥梁建筑物对于河道洪水位、流速等要素的影响程度及其变化规律.研究结果表明,河道流量越大、洪水位越高、不同桥型桥墩阻水率越大,建桥后河道壅水值、壅水范围以及流速变化值、变化范围也越大;相同流量及相同桥墩阻水率情况下,河道水面纵比降越大,建桥后桥墩附近壅水及流速变化最大值越大,但壅水及流速变化影响范围却相对较小.研究成果可为工程初步选址以及设计提供技术参考.

Taking the middle and lower reaches of the Yangtze River for examples,this paper studied the influence of bridge construction on the water level and velocity of the river and their variation laws by a twodimensional flow mathematical model with boundary well-fitted orthogonal-curvilinear grid.The modelling results show that if river discharge is larger and flood level is higher,the water blocking rate of the bridge pier will be larger,the variation values of water level and velocity after the project will be greater,and the variation ranges will be larger;with the same river discharge and bridge blocking rate,if the longitudinal water surface slope is larger,the variation values of water level and velocity after the project will be greater;but the variation ranges will be smaller.The research results can provide technical reference for the engineering site preliminary option and for design.