大跨度桥梁基础围堰施工安全对桥梁基础的顺利实施具有重要意义。湖北李埠长江大桥是世界上最大跨度的钢桁梁斜拉悬索协作体系桥,其主塔基础工程位于倾斜岸坡位置。针对其平面尺寸超百米的锁扣钢管桩围堰施工过程进行了力学分析,获得了施工全过程围堰的变形和受力响应,并通过现场监测数据对计算结果进行了对比验证。结果表明:施工过程中锁扣钢管桩围堰的变形与受力状态均满足设计要求;围堰水平变形、受力和内支撑轴力均出现了先增后减的趋势,在封底与承台浇筑阶段达到最大值,最大变形出现在江侧中心位置的钢管桩顶部;各工况钢管桩水平位移、钢管桩弯矩以及内支撑轴力的计算值与实测值整体趋势基本吻合;计算方法适用于桥梁深水桩基围堰分析。研究成果可为类似岸坡位置围堰设计与施工提供参考。

The construction safety of large-span bridge foundation cofferdams is crucial to ensuring the smooth implementation of foundation works. The Libu Yangtze River Bridge in Hubei Province is the world's longest span steel-truss-girder cable-stayed suspension cooperative system bridge. Its main tower foundation is located in the inclined bank slope position. The mechanical behavior during the construction process of the locking steel pipe pile cofferdam, with a planar dimension exceeding 100 meters was examined. Through detailed calculations and analysis, the deformation and stress responses of the cofferdam throughout the construction process were determined. The validity of these calculations was corroborated by actual monitoring data. The findings indicate that the deformation and stress states of the locking steel pipe pile cofferdam during construction conform to the design specifications. Observations revealed that the horizontal deformation, stress, and internal support axial force of the cofferdam initially increased, reaching peak values during the bottom sealing and pier pouring stages, before subsequently decreasing. The maximum deformation was observed at the top of the steel pipe pile located at the river's center. The calculated horizontal displacement and bending moment values of the steel pipe pile and the internal support axial force under various conditions closely align with the overall trends of the measured data. This calculation method proves to be effective for analyzing deep-water pile foundation cofferdams for bridges and can serve as a reference for the design and construction of cofferdams in similar inclined bank slope locations.