钢套箱围堰设计及在深水高桩承台中的应用

Design for Cofferdam with Steel Jacket and Its Application for Immersed High Pile Cap

沪昆铁路园泄泾特大桥位于上海市松江区境内的园泄泾河段,大桥长2 813 m,主跨采用2-64 m钢桁梁,主墩位于航道中心,采用高桩承台,基础采用钢管桩。园泄泾河为Ⅲ级航道通航,水深11 m且过往船只多,如何解决好深水基础施工是本桥的重点和难点。文章通过方案比选,确定采用钢套箱围堰,对钢套箱围堰及其吊挂系统进行设计、检算,对施工方案进行优化,指导施工。简要介绍半封闭式有底钢套箱围堰的设计方案、施工工艺流程、操作要点及所需材料设备等。该围堰拼装及安装简便,定位控制精确,无需大量水上施工设备及钢板桩,作业时不影响通航,加快了深水高桩承台水中基础的施工速度。

The Yuanxiejing super major bridge on Shanghai-Kunming railway is located at the Yuanxiejing river reach in Songjiang district of Shanghai. The bridge is 2 813 m long. Its main span is composed of 2 - 64 m steel truss girders, its main piers located in the middle of the navigable channel with high rise pile cap and its foundation is composed of the steel pipe piles. The Yuanxiejing river, 11 m in depth, is a grade 111 busy watercourse. How to solve the deep foundation construction is the key and difficult point for this bridge. Through scheme comparison, employment of steel boxed coffer- dam has been determined. The design and calculation have been done for the steel boxed cofferdam and its hanging sys- tern and the construction plan has been optimized to guide the construction. This paper briefly introduces the semi-en- closed bottoms of steel box cofferdam, the design scheme, construction technological process, key points of operation and the necessary materials and equipment, etc. The cofferdam assembling and installation is simple, accurate for posi- tioning control, without a large number of water construction equipment and steel sheet pile, without shipping influence during construction, simultaneously speeding up the construction of foundation with high rise pile cap in deepwater.