鳊鱼洲长江大桥5号桥塔墩钢围堰施工关键技术  

Key Construction Techniques for Steel Cofferdam of Pylon Pier No.5 of Bianyuzhou Changjiang River Bridge

作　　者：连居[1] LIAN Ju(The Fifth Engineering Co.,Ltd.,China Railway Major Bridge Engineering Group,Jiujiang 332001,China)

机构地区：[1]中铁大桥局集团第五工程有限公司,江西九江332001

出　　处：《世界桥梁》2021年第3期34-39,共6页World Bridges

摘　　要：新建安九铁路鳊鱼洲长江大桥主桥为主跨672 m的钢箱混合梁斜拉桥,5号桥塔墩采用整体式承台、群桩基础,承台施工采用矩形双壁钢套箱围堰,围堰尺寸为59.4 m×40.6 m×26.5 m。围堰在加工厂分节分块加工,水运至墩位,利用浮吊进行拼装,首先在钢平台上拼装围堰底节,焊接成整体后采用连续千斤顶吊挂下放,浇筑刃脚混凝土;然后接高第2节围堰,吸泥下沉至设计标高,再安装顶节围堰(视水位情况);最后进行围堰内清理及封底水下混凝土施工。通过采取大堤结构防护、坡脚挖除与河床抛填、围堰内壁板增设剪力键、围堰下放导向预偏、抛填反压、斜坡面围堰封底等施工关键技术,围堰平面位置、标高、倾斜度均在规范及设计要求范围内,围堰施工过程中大堤和围堰结构安全。The main bridge of Bianyuzhou Changjiang River Bridge on the newly-built Anqing-Jiujiang Raiwlay is a steel box hybrid girder cable-stayed bridge with a main span of 672 m.The pylon pier No.5 rests on an integral pile cap that is supported by group pile foundation.A rectangular double-wall steel cofferdam,which measures 59.4 m by 40.6 m by 26.5 m,was employed in the construction of the pile cap.The cofferdam was manufactured from sections to lifts in the fabrication yard,shipped to pier site and assembled by floating crane.The base lift was first assembled and welded to take shape on a steel platform,and then lowered into place using continuous jacks.Afterwards,the cutting edges were filled with concrete,the second lift of the cofferdam was lowered and sunk to design elevation via mud dredging,and then the top lift was lowered(depending on the water level).Once the three lifts of the cofferdam were all adjusted to the design position,the inside of the cofferdam was cleaned up and the base of the cofferdam was sealed by tremie concrete.To ensure that the plan position,elevation,inclination of the cofferdam could meet the code and design requirements,a series of techniques were employed,including adding protection structure to the embankment,digging up slope toe,riprapping the riverbed,adding shear keys to the inner plates of the cofferdam,setting pre-offset and guiding devices during cofferdam lowering,riprapping and applying backwards pressure,and sealing the slope of cofferdam.In the construction stage,the embankment and the cofferdam structure were safe.

关 键 词：斜拉桥 承台 双壁钢套箱围堰 大堤防护 河床抛填 剪力键 预偏 施工技术 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U443.162[交通运输工程—道路与铁道工程]