公安长江公铁两用特大桥4号墩钢围堰施工技术  

Construction Techniques of Steel Cofferdam for Pier No.4 of Gong′an Changjiang River Rail-cum-Road Bridge

作　　者：杨齐海[1] 何加江[1] 

机构地区：[1]中铁大桥局集团有限公司,湖北武汉430050

出　　处：《桥梁建设》2015年第5期99-104,共6页Bridge Construction

摘　　要：公安长江公铁两用特大桥主桥为(98+182+518+182+98)m的双塔双索面钢桁梁斜拉桥,4号桥塔墩采用变直径钻孔摩擦桩基础。4号墩基础施工采用双壁钢套箱围堰方案,钢围堰为圆端形结构,长68.2m、宽40.0m、高23.7m(分为2节,底节高16.0m),双壁厚2.0m。钢围堰底节在岸上制造,采用气囊断缆法下水,下水坡度从1∶10调整为1∶7,设置地锚、钢凳、底托板与底托架,并设置了48个规格为1.2m×8.5m的气囊;钢围堰下水自浮,待钢围堰稳定后,利用3艘拖轮联结编队进行长距离整体浮运,将钢围堰浮运至墩位处;在墩位处采用无导向船重锚锚碇系统进行快速精确定位。该桥钢围堰顺利下沉到位,经检测钢围堰最大平面偏差小于5cm,最大垂直度偏差小于1%。The main bridge of Gong＇an Changjiang River Rail-cure-Road Bridge is a steel truss girder cable-stayed bridge with double pylons, double cable planes and with span arrangement （98 ＋182＋518＋182＋98） m. The foundation for the pylon pier No. 4 of the bridge is the one of fric- tional bored piles of variable diameters and was constructed by the scheme of double-wall steel boxed cofferdam. The cofferdam is a round-end structure that is 68.2 m long, 40.0 m wide and 23.7 m high （divided into two lifts with the first lift being 16.0 m high） and the thickness of the double walls of the cofferdam is 2.0 m. The first lift of the cofferdam was manufactured on bank, launched to the river by the air bags and by cutting the connecting cables. The slope for launching of the cofferdam was adjusted from 1 ; 10 to 1 ～ 7, the ground anchors, steel stands, base support plates and base support framework were arranged and 48 air bags, each in dimensions of ～1.2 m× 8.5 m, were arranged as well. The cofferdam floated in the river by itself after it was launched there. At the time the cofferdam became stable, 3 tug boats were connected into a fleet to integral- ly float the cofferdam to the pier site in long distance. At the pier site, the cofferdam was rap!dly and accurately positioned by the heavy anchor system without utilizing the guiding barges. The cofferdam was finally smoothly sunk down in place and the inspection showed that the maximum plan tolerance of the cofferdam was less than 5 cm while the maximum verticality tolerance was less than 1%.

关 键 词：公路铁路两用桥 斜拉桥 桩基础 钢围堰 气囊法下水 浮运 定位 桥梁施工 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U445.55[交通运输工程—道路与铁道工程]