深水大跨桥梁水中墩锁口钢管桩围堰施工技术研究

Research on the Construction Technology of Locking Steel Pipe Pile Cofferdam for In-Water Pier of Long Span Bridge

在建嘉陵江特大桥为主跨200 m的预应力混凝土刚构桥,桥址位于亭子口水电站下游1.45 km处,深水急流环境为大跨度桥梁水中墩安全施工带来极大挑战。在已有研究基础上,结合工程实际,提出采用整体受力性能较好的CO型锁口钢管桩围堰方案。本文对CO型锁口钢管桩围堰设计和施工方法进行深入探讨,并采用大型有限元软件MIDAS建立有限元模型,计算分析锁口钢管桩围堰在施工过程中的应力及变形状态。计算结果表明:围堰结构的应力及变形均在设计范围以内,满足规范要求,可为后期同类结构施工提供技术支持。

Jialingjiang Bridge is a prestressed concrete rigid frame bridge with main span of 200 m, which located 1.45 km downstream of Tingzikou Hydropower Station, deep-water and rapids environment brings great challenges to the safe construction of long span bridge piers. On the basis of existing research results, combined with the engineering practice, the CO type locking steel pipe pile cofferdam with excellent overall mechanical properties is proposed. In this paper, the design and construction method of CO type locking steel pipe pile cofferdam are discussed deeply, the stress and deformation of locking steel pipe pile cofferdam are calculated with the finite element software MIDAS. The results show that the stress and deformation of the cofferdam are within the scope of design, meet standard requirement, it can provide technical support for the construction of similar structure.