马鞍山公铁两用长江大桥主航道桥Z4号墩围堰施工关键技术  

Key Construction Techniques for Cofferdam of Pier Z4 of Main Navigation Channel Bridge of Maanshan Changjiang River Rail-cum-Road Bridge

作　　者：顿琳[1,2] 王令侠 DUN Lin;WANG Ling-xia(China Railway Major Bridge Engineering Group Co.,Ltd.,Wuhan 430050,China;State Key Laboratory of Intelligent and Green Bridge Construction,Wuhan 430034,China)

机构地区：[1]中铁大桥局集团有限公司,湖北武汉430050 [2]桥梁智能与绿色建造全国重点实验室,湖北武汉430034

出　　处：《桥梁建设》2023年第2期10-16,共7页Bridge Construction

基　　金：中国铁路上海局集团有限公司科研计划课题(2021227)。

摘　　要：马鞍山公铁两用长江大桥主航道桥为(112+392+2×1120+392+112)m三塔钢桁梁斜拉桥,Z4号墩承台为矩形倒圆角结构,平面尺寸89.2 m×54.7 m,高10 m。承台采用先平台后围堰方案施工,围堰为双壁钢套箱结构,平面尺寸93.6 m×59.1 m,高35 m,高度方向上分为4层(顶节为单壁,其余为双壁)。底节围堰采用分块制造、水中浮态连接的施工技术,解决了围堰在长江航道整体制造、运输的难题,同时简化了施工工序,保证了围堰快速化施工。底节拼装后对称、分块接高第2节和第3节双壁钢套箱围堰,然后分区取土下沉,通过在围堰各分块上设置高精度空间姿态测量装置,依据数据分析结果动态调整围堰分块后拼接角度及下沉过程中的姿态,保证了围堰顺利下沉到位。底隔舱和封底混凝土采用插管法分区、交替浇筑,并在底隔舱上增加横向支撑,解决了因底隔舱跨度较大,封底混凝土灌注时底隔舱和围堰侧板连接处受力较大的问题。围堰抽水后封底混凝土止水效果良好,已顺利完成承台浇筑施工。The main navigation channel bridge of Maanshan Changjiang River Rail-cum-Road Bridge is a three-tower,steel truss girder cable-stayed bridge,with two main spans of 1120 m,two side spans of 392 m and two end spans of 112 m.The pier Z4 stands on a rectangular,round-cornered pile cap that measures 93.6 m×59.1 m,10 m in height.During the pile cap construction,a working platform was installed ahead of the lowering of the cofferdam.The cofferdam,which is a double-wall steel box structure measuring 93.6 m×59.1 m,35 m in height,consists of four lifts(the top lift has one-layer of walls,and the remaining lifts have two layers of walls).To resolve the problems of integral manufacturing and transportation of the cofferdam in the Changjiang River navigation channel,the bottom lift were first manufactured into individual blocks,which were then pushed to float over river for splicing.As a result,the construction procedure was simplified and the rapid construction of the cofferdam was guaranteed.Once the bottom lift took shape,the second and third lifts were assembled and added up in a symmetrical and block-by-block manner.Afterwards,excavation was carried out in different zones to assist the sinking of the cofferdam.High-precision spatial attitude measuring devices were installed on the blocks of cofferdam to dynamically adjust the splicing angles of the blocks and position of cofferdam during sinking,to ensure the smooth landing of the cofferdam.Tremie pipes were laid out in the bottom cells to cast the bottom sealing concrete,and the concrete in cells in different zones were alternately cast.Lateral struts were added on the bottom cells to provide support to the large-size cells and counteract the excessive loads at the connections between bottom cells and cofferdam walls.After dredging,the waterproof effect of the bottom sealing concrete was proved good,and the pile cap casting construction was performed smoothly.

关 键 词：公路铁路两用桥 斜拉桥 承台 双壁钢套箱围堰 围堰设计 浮态连接 施工技术 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]