五峰山长江大桥北锚碇沉井基础变形分析  

Caisson Foundation Deformation Analysis for North Anchorage of Wufengshan Changjiang River Bridge

作　　者：冯传宝 FENG Chuan-bao(Construction Headquarters of Nanjing Railway Terminal Project,China Railway Shanghai Bureau Group Co.,Ltd.,Nanjing 210042,China)

机构地区：[1]中国铁路上海局集团有限公司南京铁路枢纽工程建设指挥部,江苏南京210042

出　　处：《桥梁建设》2021年第1期74-81,共8页Bridge Construction

基　　金：中国铁路总公司科技开发计划项目重大课题(2017G006-A)。

摘　　要：连镇铁路五峰山长江大桥主桥为主跨1092m的公铁两用钢桁梁悬索桥,北锚碇采用100.7m×72.1m×56m的矩形沉井基础。为了解沉井基础在施工过程中的变形及其对后续施工的影响,采用Abaqus软件建立沉井-地基以及沉井与邻近桩基础有限元模型,结合现场监测数据,针对沉井基础底板施工至主梁架设的11个工况,分析沉井基础变形与受力状态、地基土应力路径及邻近桩基础的变形。结果表明:沉井基础以沉降变形为主,水平变位和整体转动量相对较小;不同工况下,沉井基础井壁与底板受力状态变化显著;沉井底板下地基土应力路径位于强度破坏线下方,地基土未发生破坏,其变形以压缩变形为主;邻近桥墩基础的竖向和横桥向位移受沉井基础施工的影响较小;计算结果较准确地预测了沉井基础和邻近桩基的沉降和水平变形,有效地指导了北锚碇散索鞍的定位及引桥段合龙施工。The main bridge of Wufengshan Changjiang River Bridge on Lianyungang-Zhenjiang Railway is a steel truss girder suspension bridge with a main span of 1092mand carries both highway and railway traffics.The north anchorage is supported by a rectangular caisson foundation measuring 100.7mby 72.1m,and 56min depth.To predict the deformation of the caisson foundation during construction and the ramifications,the caisson-soil model and caisson-nearby piles model were built up by Abaqus to simulate the 11construction stages that start from the caisson base plates assembly and work towards superstructure erection.The deformation and load bearing condition of the caisson foundation,stress paths of soil and the deformation of the nearby piles were analyzed,considering the monitored data on site.The results show that settlement is the main issue of caisson foundation,and the horizontal displacement and global rotation are relatively small.Loading conditions of the caisson sidewalls and base plates exhibited significant changes in different construction stages.The stress paths of soil beneath the base plates of the caisson existed under the strength failure line,indicating that the soil had not yet failed and mainly underwent compression deformation.The caisson foundation construction brings little disturbance to the vertical and transverse displacements of the nearby pier foundations.The settlement of the caisson foundation and the horizontal deformation of the nearby piles were predicted by numerical modeling with relatively high accuracy,which contributed to the success of the positioning of the splay saddle of north anchorage and the closure of approach bridges.

关 键 词：公路铁路两用桥 悬索桥 锚碇 沉井基础 基础沉降 变形 受力 有限元法 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U443.131[交通运输工程—道路与铁道工程]