新型组合结构围堰钢-混连接段关键技术

Key Construction Technology for Steel⁃Concrete Connective Section of New Type Combined Structure Cofferdam

组合结构围堰由于其环境适应能力强,施工成本可控,便于合理优化工期,近年来逐步成为桥梁基础施工建设中新兴的一种施工方法。常见的组合围堰有土石+双壁钢围堰、钢筋混凝土-钢套箱围堰、混凝土-钢板桩围堰等结构形式,而咬合桩-双壁钢围堰组合结构围堰尚属国内施工中首次运用,缺乏合理性验证。以建设中的临港长江公铁两用大桥基础施工为例,介绍组合咬合桩+双壁钢围堰。对钢-混连接段构造建立ABAQUS有限元分析模型,验算不同工况下其变形、力学特性。现场监测结果验证了有限元计算的可靠性,同时表明钢-混连接段构造结构设计的合理性。

Combined structure cofferdam is a new type of cofferdam that has gradually become a new construction method in bridge foundation construction in recent years because of its advantages in environmental adaptability,controllable costs and optimization in construction period.The most common combined structure cofferdam includes soil and rock-double wall steel cofferdam,reinforced concrete and steel box cofferdam,concrete-steel sheet pile cofferdam etc.It is the first time to use the combined structure cofferdam of secant pile-double wall steel cofferdam in domestic construction,which is lack of rationality verification.Taking the foundation construction of the Lingang Yangtze River rail-cum-road bridge as an example,the combined structure cofferdam of secant pile-double wall steel cofferdam was introduced.The ABAQUS finite element analysis model was established for steel-concrete connected section to check the deformation and mechanical properties under different working conditions.The field monitoring results verify the reliability of the finite element calculation and the rationality of the structural design of the steel-concrete connected section.