摘要
以在建的河北省怀来县官厅水库悬索桥北锚碇沉井基础为研究对象,对沉井的首次下沉施工过程进行了实时监测。根据现场监测数据,分析了沉井下沉过程中刃脚和分区隔墙底部应力的变化规律。同时,对沉井下沉过程进行了有限元模拟分析。研究结果表明:刃脚和分区隔墙底部水平(竖向)钢筋应力、钢板水平(竖向)应变均呈现出增加和减小反复变化的规律,且总体趋势都是在减小,分区隔墙的钢筋应力和钢板水平应变均大于刃脚处的,而分区隔墙钢板竖向应变小于刃脚处的;沉井下沉的初期(入土深度2.98~3.43m)是最不利于结构安全的时期,也是下沉过程结构安全监测的重点时期;下沉过程中沉井结构处于非线弹性工作状态;下沉前地基加固的刚度不宜过大;在进行沉井设计时可取"大锅底"且将刃脚土体固结作为控制工况。
The north anchorage caisson foundation of the suspension bridge at Guanting Reservoir of Huailai in Hebei Province is considered as a study object,the first subsidence construction process of caisson is monitored in real time.According to the observed field data,the change of stress at the blade feet and the bottom of the partition wall is systematically studied.At the same time,the finite element simulation during the subsidence process is carried out.The results show that,at the blade feet and at the bottom of the partition wall,the stress of steel bars and the strain of steel plates all obey the law of increasing and decreasing alternately,and the overall trend is decreasing.the stress of steel bars and the horizontal strain of steel plate at the partition wall are larger than that at the blade feet,but the vertical strain of steel plate at the partition wall is smaller than that at the blade feet.The primary stage of sinking(buried depth of 2.98~3.43 m)is the most dangerous period for structural safety,and it is also the key period of structural safety monitoring.In the process of sinking,the caisson structure will always be in a non-linear elastic state.The stiffness of foundation reinforcement should not be too large before caisson sinking.It is advisable to use‘big pot bottom’and consolidated soil at the blade feet as controlled conditions when the caisson is designed.
作者
黄迪
朱劲松
祁海东
HUANG Di;ZHU Jin-song;QI Hai-dong(School of Civil Engineering,Tianjin University,Tianjin 300072,China;MunicipalConstruction Administration Department of Huailai,Huailai 075400,China)
出处
《交通科学与工程》
2018年第1期40-49,共10页
Journal of Transport Science and Engineering
基金
国家自然科学基金项目(51578370)
天津市科技支撑计划重点项目(16YFZCSF00460)
关键词
沉井基础
下沉过程
现场监测
有限元模拟
应力变化规律
caisson foundation
subsidence process
field monitoring
finite element simulation
variation law of stress