桥区河段的洲滩演变,可能会改变桥区的航道条件,影响船舶通航。武汉长江大桥所在的武桥水道河段汉阳边滩年内呈现汛冲枯淤的规律,如果枯水期汉阳边滩淤积展宽,武汉长江大桥上水通航孔水深不足,不能通航,或者即使水深足够,但因桥位上游的航槽过于弯曲,上水船舶通航困难,常需要调标改孔,严重时必须采取疏浚措施。将二维水流数学模型与船舶运动漂移量模型相结合,计算分析了汉阳边滩不同淤积形态条件下上行船舶通过大桥上游弯道的所需航宽,从船舶运动学角度分析了汉阳边滩淤积展宽影响桥区通航的机理。结果表明,即使4 m等深线没有直接淤积通航桥孔,当汉阳边滩突咀较大且靠近大桥时,桥位上游弯道宽度不满足上水船舶安全通航所需航宽的要求,必须采取相应措施。
Due to the river channel process in the bridge reaches, there are great changes in the navigation channelconditions and impacts upon ship navigation. The Hanyang alternative bar in the Wuqiao waterway sustains the lawof “ erosion in flood, and siltation during dry season”. If the upward navigation span of the Wuhan Yangtze RiverBridge is clogged by the 4 m isobath curve of the Hanyang alternative bar during a dry period, navigationobstruction takes place. Even if the water depth in the navigation openings meets the navigation requirements, thenavigation channel in the upstream of the bridge bends seriously as a result of the siltation of the Hanyangalternative b ar, which makes a difficult situation for upward vessels, thus an adjustment of the navigation openingsor even dredge maintenance is needed. In this paper, a two-dimensional flow mathematical model and a ship motiondrift model are firstly integrated to calculate the necessary widths for the upward vessels passing through the bendchannel with different siltation morphologies of the alternative bar. Then the authors analyze the navigationobstruction mechanisms of the Hanyang alternative bar from the point of view of ship kinematics. The analysisresults show that the actual bend fairway’s width in the upstream of the bridge does not meet the requirements for thesafe pass of the typical ship when there is a heavy deposition along the Hanyang alternative b ar, which is close tothe bridge, and that it is necessary to take proper measures for the safe navigation of the upward vessels.