蒙华铁路洞庭湖特大桥主墩基础施工关键技术  

Key Construction Techniques for Foundation of Main Pier of Dongting Lake Bridge on Mengxi-Huazhong Railway

作　　者：贾卫中[1] 孟超[2] JIA Wei-zhong;MENG Chao(China Railway Major Bridge Engineering Group Co.,Ltd.,Wuhan 430050,China;National Railway Administration of the People＇s Republic of China Construction Quality Supervision Center,Beijing 100891,China)

机构地区：[1]中国中铁大桥局集团有限公司,湖北武汉430050 [2]国家铁路局工程质量监督中心,北京100891

出　　处：《桥梁建设》2018年第5期1-5,共5页Bridge Construction

摘　　要：蒙华铁路洞庭湖特大桥主桥为(98+140+406+406+140+98)m三塔双索面钢箱钢桁结合梁斜拉桥,主墩均采用22根3.0m嵌岩钻孔桩基础,主墩基础采用50.5m双壁钢套箱围堰平台一体法施工。围堰采用气囊法下河,对围堰下河的3个阶段进行连续化理论推导和验证,并利用GPS监测围堰下河全过程,解决了大型圆形双壁钢套箱围堰下河易搁浅的难题;采取短锚定位技术,使围堰占用水域面积仅为前、后定位船锚碇系统的1/8,解决了狭窄水域围堰下沉定位的难题;钻孔桩施工采用"桩周注浆预加固+优质PHP泥浆护壁+加装钻头稳定器"的组合新工艺,解决了复杂地质中深水大直径嵌岩桩的施工难题。该桥主墩基础施工已完成,钻孔桩经检测均为Ⅰ类桩。The main bridge of Dongting Lake Bridge on Mengxi Huazhong Railway is a steel box steel ＂truss composite girder cable-stayed bridge with three pylons, double cable planes and with span arrangement （98＋140＋406＋406＋140＋98） m. The foundation of ＂the main pier is ＂the one consisting of 22 bored piles built in rock stratum with ＂the diameter of φ3.0 m, and ＂the founda tions are constructed using the integral method of a φ50.5 in double-wall steel box cofferdam plat form. The cofferdam was launched to the river by the air bag method, and the three stages of launching the cofferdam were derived and verified using the continuous theory. Meanwhile, the whole process of launching the cofferdam was monitored by GPS, and the problem that the large circular double-wall steel cofferdam was easy to strand during launching was solved. The short an chor location technique was used to make the water area occupied by the cofferdam was only 1/8 of the one between the front and rear location ship anchorage system, and the problem about the launching location of the cofferdam in the narrow waters was solved. The new combined technolo gy that ＂grouting pre reinforcement around piles ＋ wall protection by the high quality PHP mud＋ installing the boring bit stabilizer＂ was adopted for the construction of the bored piles, and the construction problem of the deep water large diameter bored piles built in rock stratum in complex geology was also resolved. The construction of the main pier foundations of the bridge had been compleleted, and all the bored piles were tested as class I.

关 键 词：重载铁路桥 斜拉桥 钻孔桩 钢套箱围堰 气囊法下河 短锚定位 成孔措施 桥梁施工 

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]