河床演变影响下桥区水域通航安全研究

Study on navigation safety under influence of riverbed evolution in bridge area

为了科学地设定滩槽易变河段处的桥梁跨径布置方案,针对荆州长江大桥桥区水域河床演变影响通航安全的问题,采用实例调研及历史资料分析的方法,指出滩槽易变河段选址建设的桥梁,其最大风险是滩槽移位导致船舶从通航孔位置移动到非通航孔位置,提出新建桥梁通航孔布置应覆盖深泓和可能成为航道的深槽的摆动范围;根据提出的原则研究拟建的李埠桥区水域的河床演变机制,选定最低通航水位下3.5 m深槽和深泓的摆动范围作为桥跨布置的依据;最终确定的1 120 m桥跨布置方案能够保障河床影响下拟建李埠长江大桥的通航安全。

In order to scientifically design bridge span scheme for changeable riverbed,case analysis and historical analysis methods were employed to study the problem of Jingzhou Yangtze river bridge area where navigation safety was impacted by riverbed evolution. It was pointed out that the most significant risk for bridges in changeable riverbeds was that channel displacement caused by riverbed evolution made ship navigation move from navigable bridge opening to non-navigable one,and it was suggested that navigable bridge opening should cover thalweg and swing range of deep channel which may form new navigation channel. Then,riverbed evolution mechanism of Libu bridge area which was planned to be built was studied according to proposed principles,swing range of 3. 5 m deep channel and thalweg under the lowest navigable stage was chosen for bridge span layout. Finally,1 120 m scheme was confirmed to be able to guarantee navigation safety of Libu Yangtze river bridge under influence of riverbed.