Abstract: The layout of the bridge such as bridge site，the bridge spacing and span significantly affect navigation conditions of bridge group reach of the mountain river． The navigation environment of Caiyuanba Bridge group reach of Yangtze River is complex． Based on the model test，the flow condition for navigation，ship maneuvering characteristics are analyzed by the time when the bridges are completed． It is indicated that the effect of Shibanpo Bridge on the bridge group reach of Yangtze River is relatively greater，where the navigation condition is poor caused by the narrow and curved channel，as well as the insufficient navigation clearance． The main navigable hole of Caiyuanba Bridge pasts across the navigable waterway，but it is close to Shibanpo Bridge． So the descending vessels should promptly adjust the direction and position after through Caiyuanba Bridge to prepare for passing the next bridge． To ensure the safety of navigation，the security measures of bridge group should be considered overallly．

Key words: bridge group reach, waterway regulation, security measures

摘要： 山区河流桥群河段的选址、桥梁间距及桥跨布置对桥区通航条件的影响较大。长江菜园坝桥群河段通航环境 复杂，通过模型试验，按建桥的顺序研究桥梁建设对该河段通航水流条件、船舶操纵特性的影响。分析表明: 石板坡 重庆长江大桥对桥群河段通航条件的影响相对最大，航道变得狭窄、弯曲，通航净宽尺度不足，桥群河段的通航条件较差; 菜园坝大桥主通航孔虽然一跨过通航水域，但与石板坡间距较近，下行船舶在通过菜园坝大桥后应及时调整航向和船位。为保障通航安全，应整体考虑桥群河段的通航安全措施。

关键词: 桥群河段, 航道整治, 安全保障措施