西堠门公铁两用大桥主桥5号墩∅6.3 m超大直径钻孔桩施工技术  

Construction Techniques of 6.3 m-Diameter Bored Piles of Main Bridge Pier No.5 of Xihoumen Rail-cum-Road Bridge

作　　者：彭颇[1] 吕晓平 PENG Po;LYU Xiaoping(The Fifth Engineering Co.,Ltd.,China Railway Major Bridge Engineering Group,Jiujiang 332001,China;Huhang Railway Passenger Dedicated Lines Co.,Ltd.,Shanghai 200070,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 [2]沪杭铁路客运专线股份有限公司,上海200070

出　　处：《桥梁建设》2025年第2期18-24,共7页Bridge Construction

基　　金：中国中铁股份有限公司科技研究开发计划课题(2021-专项-02)。

摘　　要：甬舟铁路西堠门公铁两用大桥主桥为主跨1488 m的斜拉-悬索协作体系桥,5号墩采用18根∅6.3 m超大直径钻孔桩基础,桩长84 m,采用C45水下混凝土,单桩混凝土方量约3000 m 3。5号墩墩位处水深流急,地质条件复杂,结合桥位处复杂海洋环境和主体结构特点,5号墩基础平台施工后,采用引孔跟进法埋设钢护筒,在钢护筒内扩孔,采用液压冲击锤插打钢护筒,跟进至设计标高,解决了深水裸岩地质条件下钢护筒埋设难题;钻孔桩采用旋挖钻机分级成孔或全回转钻机全断面一次成孔,解决了超大直径钻孔桩成孔难题;钢筋笼采用长线法制作,利用400 t龙门吊翻身、对接、下放,采用悬挂环进行支撑及悬挂定位,解决了带中心钢管的超大直径钢筋笼施工难题;桩基水下混凝土采用双导管法灌注工艺,解决了超大直径钻孔桩混凝土灌注难题。采用超声波自动循测仪RSM-SY7(F)进行桩身完整性检测,结果表明18根∅6.3 m超大直径钻孔桩均为Ⅰ类桩。The main bridge of Xihoumen Rail-cum-Road Bridge of Ningbo-Zhoushan Railway is a hybrid cable-stayed suspension bridge with a main span of 1488 m.Pier No.5 is supported by 18,∅6.3 m bored piles of 84 m in length.The bored piles are cast by C45 tremie concrete,and a single pile consumes about 3000 m 3 concrete.Pier No.5 is located at an offshore zone with swift currents,where the geological conditions are complex.To accommodate the complicated marine environments and the attributes of main bridge structure,a hole-guiding follow-up method was applied to bury the steel casings after the installation of platform for foundation construction.The borehole was expanded inside the steel casing,and the steel casing was driven by a hydraulic hammer to the design elevation,resolving the burying of steel casings in the offshore bare rock zone.The borehole took shape in phases using the rotary drilling rig and/or in a one-off full-cross-section formation manner using the casing rotator,greatly facilitating the borehole formation for the large-diameter bored piles.The reinforcing cage was fabricated by a long-line method,and turned,butt-jointed and lowered by a 400 t-capacity gantry crane.Each of the steel casing featuring a center steel tube was supported/positioned and hung via suspension rings.The pile concrete was cast by a double-tremie-pipe approach.The intactness of the piles was tested by the ultrasonic automatic tracking device RSM-SY7(F).The test results demonstrate that all the 18,∅6.3 m bored piles reach the GradeⅠ-listed pile.

关 键 词：公路铁路两用桥 斜拉-悬索协作体系桥 超大直径钻孔桩 钢护筒 钢筋笼 分级成孔 双导管灌注 施工技术 

分 类 号：U448.121[建筑科学—桥梁与隧道工程] U443.154[交通运输工程—道路与铁道工程] U445.4