重庆官栈河大桥主桥主墩基础锁口钢管桩围堰加固  

Strengthening of Interlocking Steel Pipe Pile Cofferdam Used in Main Pier Foundation Construction of Guanzhanhe River Bridge in Chongqing

作　　者：钱骥[1,2] 荚瑞馨 宋世杰 杨纪鹏 QIAN Ji;JIA Ruixin;SONG Shijie;YANG Jipeng(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;State Key Laboratory of Bridge and Tunnel Project in Mountainous Area Jointly Built by Province and Ministry,Chongqing 400074,China)

机构地区：[1]重庆交通大学土木工程学院,重庆400074 [2]重庆交通大学山区桥梁与隧道工程国家重点实验室,重庆400074

出　　处：《桥梁建设》2024年第1期148-154,共7页Bridge Construction

基　　金：中国博士后科学基金项目(2021M702782);重庆市自然科学基金项目(CSTB2023NSCQ-MSX0633)。

摘　　要：重庆官栈河大桥主桥为(62+110+62)m三跨连续刚构桥,主墩基础采用锁口钢管桩围堰施工。围堰施工正常水位+325.300 m,施工期控制水位+330.500 m。在该桥主墩围堰完成四周锁口钢管桩插打及前4道内支撑安装后,因极端天气原因,长寿湖水位上涨到+332.200 m,危及围堰安全。为解决钢管桩围堰的安全问题,提出采用水下施工内支撑的加固方案。待围堰内部水头与外部保持一致后,将已经插打的锁口钢管桩加高至标高+334.000 m,拆除已安装好的4道内支撑,重新安装6道内支撑。采用MIDAS Civil软件分别建立加固前、后钢管桩围堰结构有限元模型,分析钢管桩及内支撑的受力安全与稳定性。结果表明:施工控制水位+330.500 m下,围堰结构最大正应力由加固前的162.6 MPa下降到加固后的82.3 MPa,下降了49.3%;承载水位可从施工控制水位+330.500 m增加到目标控制水位+333.500 m,且强度和刚度等均留有一定储备。水下施工内支撑的加固方案可提升围堰的承载能力。该桥围堰加固后整体受力效果良好,已顺利完成承台浇筑施工。The main bridge of Guanzhanhe River Bridge in Chongqing is a three-span continuous rigid-frame bridge with a main span of 110 m and two side spans of 62 m.The interlocking steel pipe pile cofferdam was used to facilitate the construction of the main pier foundation.During the construction of the cofferdam,the normal water level was+325.300 m and the control water level was+330.500 m.When the interlocking steel pipe piles circling the cofferdam were driven into position and the first four layers of inner supports were installed,the extreme weather induced the water level to rise and reach+332.200 m,posing a threat to the safety of the cofferdam.In order to solve the safety problem of steel pipe pile cofferdam,the reinforcement scheme of installing internal support under underwater condition is proposed.After the internal water head of the cofferdam is consistent with that of the outside,the locked steel pipe pile is raised to the elevation of+334.000 m,the previously-installed 4 internal supports are removed,and another 6 internal supports are installed.The finite element models of the steel pipe pile cofferdam before and after the strengthening were built up in MIDAS Civil to analyze the load bearing safety and stability of the steel pipe piles and inner supports.It is shown that at a control water level of+330.500 m,the maximum normal stress of the cofferdam fell from+330.500 m before strengthening to 82.3 MPa after strengthening,decreased by 49.3%.The load bearing water level rose from the control level of+330.500 m to the target control level of+333.500 m,leaving the cofferdam with a strength and rigidity margin.To install the inner supports in water can improve the load bearing capacity of the cofferdam.For the Guanzhanhe River Bridge,the cofferdam of the main pier exhibited good load bearing capacity after strengthening,and the subsequent pile cap pour was carried out smoothly.

关 键 词：刚构桥 锁口钢管桩围堰 加固 有限元法 桥梁施工 

分 类 号：U445.556[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]