武桥水道水动力特性与汉阳边滩演变

Flow characteristics of Wuqiao reach and evolution rules of Hanyang side bar

武桥水道枯水期碍航与汉阳边滩的发育程度直接相关,而汉阳边滩的冲淤变化又与该河段水动力特性有关.结合定床模型试验和原观资料分析,分析了武桥水道河段水流运动特性、汉阳边滩形成的必然性、年内年际的演变规律、汉阳边滩冲淤变化与水动力条件之间的关系.结果表明:武汉河段平面形态特征、汉江入汇以及武昌深槽是汉阳边滩形成的根本原因;该河段汛期水流动力轴线顺直,潜洲至大桥间水流动力轴线居中靠左;而枯水期水流动力轴线弯曲,水流动力轴线在潜洲尾部以下由左侧过渡到右侧的特点决定了汉阳边滩汛期冲刷,汛后以及枯水期淤积外展的规律;枯水期不同的水流条件决定了汉阳边滩淤积外展的程度及其碍航程度.

The main problem in Wuqiao reach is the navigation-obstruction of Hanyang side bar. In order to make clear the navigation obstruction mechanism of Hanyang side bar, flow characteristics and chan nel evolution characteristics has been analyzed based on approaches of model experiment and analysis of prototype observation data. The analysis indicates that the water block produced by channel constriction and bridge pier hinder, the backwater produced by Hanjiang River afflux, the sucking effect of Wuchang deep pool and the decline of right branch induces the formation of Hanyang side bar and the mainstream oblique flow from Qianzhou tail to Wuchang deep pool. In flood season, the flow dynamic axis between Wuhan Yangtze Bridge and Qianzhou is straight and near the left, while in the dry season, the axis is bend and transit from left to the right at the Qianzhou tail. The change of the flow dynamic axis brings to the intro-year variation of Hanyang side bar which presents as scours in flood period and deposits in falling stage and dry period. And the navigation obstruction degree of Hanyang side bar depends on the different flow conditions during dry period.