摘要
宁洛高速改扩建工程淮河特大桥22#墩围堰累计入水下沉34 m,嵌入河床19 m,且刃角位于泥岩地质中,在施工过程中受地质、汛期等多方面影响,围堰基坑开挖、下沉精准就位难度很大且工期紧张。设计了新型砼滚杠式限位导向,解决围堰下沉过程中的平面偏位控制难题;采用在吸泥管底部加装液压铰刀和搭设平台采取旋挖钻机钻挖取土的方法,攻克了圆砾土层和全风化泥岩层的水下开挖难题;合理调整内支撑安装顺序,优化安装工艺,极大的提高了施工效率。确保了22#墩围堰在预定工期内下沉到位并成功封底,为大挖深双壁钢围堰的基坑开挖、下沉就位施工提供了经验借鉴。
In the expansion and reconstruction project of Ningluo Expressway,the cofferdam for Pier No.22 of the Huaihe River Super Bridge was submerged to a cumulative depth of 34 meters embedded 19 meters into the riverbed,with its cutting edge located in a mudstone stratum.During construction,geological complexities and flood-season constraints posed significant challenges in both precise foundation pit excavation and accurate cofferdam positioning,under a tight schedule.A novel concrete rollerbar limit-and-guide system was designed to control horizontal displacement through the sinking process.By installing a hydraulic reamer at the bottom of the suction pipe and utilizing a rotary drilling rig on a specially erected platform to drill and remove soil,the difficulties of underwater excavation in gravel layers and completely weathered mudstone were effectively overcome.In addition,the installation sequence of the internal supports was optimized to significantly improve construction efficiency.As a result,the Pier No.22 cofferdam successfully reached its designated depth and was sealed at the bottom within the scheduled time.The lessons learned from this project offer valuable references for excavating foundation pits and conducting sinking-and-positioning operations of double-wall steel cofferdams with large excavation depths.
作者
孟金强
MENG Jinqiang(Railway Combat Readiness Pontoon Bridge Division,Qihe 251100,China)
出处
《国防交通工程与技术》
2025年第1期45-49,85,共6页
Traffic Engineering and Technology for National Defence
关键词
双壁钢围堰
深水泥岩
精准就位
砼滚杠式限位导向
内支撑安装
double-wall steel cofferdam
deep water mudstone
precise positioning
concrete roller bar limit-and-guide system
internal support installation
