张靖皋长江大桥南航道桥北锚碇地下连续墙施工工艺试验研究  

Experimental Study on Diaphragm Wall Construction Techniques for North Anchorage of South Navigation Channel Bridge of Zhangjiagang-Jingjiang-Rugao Changjiang River Bridge

作　　者：戴俊平 李奔琦 王瑞 DAI Jun-ping;LI Ben-qi;WANG Rui(Jiangsu Traffic Engineering and Construction Bureau,Nanjing 210004,China;The Second Engineering Co.,Ltd.,China Railway Major Bridge Engineering Group,Nanjing 210015,China)

机构地区：[1]江苏省交通工程建设局,江苏南京210004 [2]中铁大桥局集团第二工程有限公司,江苏南京210015

出　　处：《桥梁建设》2023年第3期1-7,共7页Bridge Construction

基　　金：国家重点研发计划项目(2022YFB3706700)。

摘　　要：张靖皋长江大桥南航道桥为主跨2300 m的双塔双跨吊钢箱梁悬索桥,南、北锚碇基础均采用支护转结构复合地下连续墙结构。北锚碇地下连续墙(长118.05 m、宽75.05 m、深67 m)分为一期槽段(封闭钢箱混凝土结构)、二期槽段(钢筋混凝土结构),一期钢箱外伸的4道钢筋网片与二期钢筋笼外伸的2道钢筋网片采用无接触搭接,形成新型排插钢筋刚性接头。北锚碇地下连续墙采用先一期槽段后二期槽段的工艺施工。为解决排插钢筋刚性接头质量要求高、一期钢箱变形风险大、相邻槽段混凝土灌注过程中防绕流难度大等难题,采用BC40铣槽机“纯铣法”成槽,一期钢箱和二期钢筋笼采用长线法分节段匹配制作,采用特制刷壁器刷洗接头处钢筋上的泥渣,在一期钢箱两侧设置隔离箱并回填碎石,在一期钢箱侧壁与槽壁间设置注浆水袋并在注浆水袋之间回填碎石。为验证工艺的可行性和适应性,在与北锚碇地层相近处开展3个槽段(2个一期槽段和1个二期槽段)的足尺模型工艺试验。结果表明:地下连续墙成槽垂直度不大于1/800,排插钢筋搭接长度偏差不超过3 cm,接头处刷壁效果良好,施工质量满足要求;一期钢箱变形不超过4.5 mm,应力不超过18 MPa,应力和变形可控;混凝土灌注防绕流措施有效。该桥北锚碇施工工艺方案总体可行,能够指导实际施工。The south navigation channel bridge of Zhangjiagang-Jingjiang-Rugao Changjiang River Bridge is a two-tower steel box girder suspension bridge with a main span of 2300 m.Hanger cables are arranged in the main span(2300 m)and the 717 m-long section of the 1220 m-long side span.Both the south and north anchorages are supported by the composite diaphragm wall foundation which first serves as a supporting structure during the anchorage construction and is transformed into a permanent structure of the bridge after completion of the anchorage construction.The diaphragm wall foundation of the north anchorage measures 118.05 m by 75.05 m,67 m in height,consisting of the first-phase trenches(closed steel box-concrete composite structures)and the second-phase trenches(reinforced concrete structures),and the first-phase trenches and the second-phase trenches are connected via a new-type spliced reinforcement rigid joint,featuring the non-contact splicing of the four reinforcement meshes stretching out from the first-phase steel boxes and the two reinforcement meshes protruding from the second-phase reinforcement cages.For the diaphragm walls of the north anchorage,the first-phase trenches were constructed ahead of the second-phase trenches.To fulfill the critical quality requirements of the spliced reinforcement rigid joint,address the high-likelihood deformation risk of steel boxes and overcome the circumferential flows during concrete casting in the adjacent trench,the Hydromill BC40 is employed for trench excavation,the steel boxes for the first-phase trenches and the reinforcement cages for the second-phase trenches are manufactured by the long-line match method.A tailored trench wall brush is used to clean the muds on the reinforcement at the joint,isolation boxes are installed on the two sides of the steel box of the first-phase trench and backfilled with gravels,and between the steel box wall and trench wall,water bags are laid out and the gaps of the water bags are backfilled with gravels.To verify the applicability

关 键 词：悬索桥 锚碇 地下连续墙 排插钢筋刚性接头 一期钢箱 二期钢筋笼 防绕流 足尺模型试验 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U443.24[交通运输工程—道路与铁道工程]