摘要
现行沉井规范主要针对中小沉井,由于沉井平面尺寸越来越大,超大型沉井终沉阶段的受力机理有待研究。本文以常泰长江大桥5#墩沉井为研究对象,运用相关理论方法对5#墩沉井终沉以及封底过程进行分析,提出两圆端支撑下沉法,同时研究了隔墙底部应力分布、沉井侧摩阻力,并对两圆端支撑下的沉井、沉井封底过程进行了有限元模拟。研究结果表明:通过及时动态调整可以保证沉井良好的姿态;沉井在终沉过程中端阻力、侧摩阻力分别占总阻力的55%、45%,动摩阻力系数与静摩阻力系数之比为0.63;两圆端支撑下沉法通过减少端阻力,实现了大型水中钢沉井没有任何助沉措施下,顺利快速下沉;沉井封底施工过程中,通过合理的浇筑顺序可以保证沉井钢壳以及混凝土均在可控的安全范围内。
At present,open caisson foundation has been widely used in large-scale bridge construction.The current open caisson specifications are mainly for small and medium-sized open caisson.With the increasing plane size of open caisson,the stress mechanism of super large open caisson in the final settlement stage needs to be studied.In this paper,the engineering background is the 5#pier of Changtai Yangtze River Bridge with the largest round end stepped steel open caisson in water.The final settlement and bottom sealing process of the 5#pier open caisson were analyzed using the relevant theoretical methods,and the two round ends support sinking method was proposed.At the same time,the stress distribution at the bottom of the partition wall,the side friction of the sink and the finite element simulation of the open caisson and the bottom sealing process of the open caisson under the two round ends support were studied.The results show that the good posture of open caisson can be ensured by timely dynamic adjustment.During the final sinking process of open caisson,the end resistance and side friction account for 55%and 45%of the total resistance respectively,and the ratio of dynamic friction coefficient to static friction coefficient is 0.63.For the first time,the two round ends support sinking method reduces the end resistance and realizes the smooth and rapid sinking of large underwater steel open caisson without any settlement assistance measures.During the construction of caisson bottom sealing,the steel shell and concrete of caisson can be ensured within the controllable safety range through reasonable pouring sequence.The research results can provide important guidance for the construction of large underwater steel open caisson.
作者
朱浩
杨切
ZHU Hao;YANG Qie(CCCC Second Harbor Engineering Co.Ltd.,Wuhan 430040,China;Key Laboratory of Transportation Sector for Long-Span Bridge Construction Technique,Wuhan 430040,China;Transportation Infrastructure Intelligent Manufacturing Technology Research and Development Center,Wuhan 430040,China;CCCC Highway Bridge National Engineering Research Centre Co.Ltd.,Beijing 100032,China)
出处
《铁道建筑》
北大核心
2022年第6期87-92,共6页
Railway Engineering
基金
中国交通建设股份有限公司科技研发项目(EHYF-2020-B-04-052)。
关键词
常泰长江大桥
沉井
施工监测
封底
侧摩阻力
端阻力
姿态控制
Changzhou-Taizhou Yang River Bridge
open caisson
construction monitoring
bottom sealing
side friction
end resistance
posture control
