常泰长江大桥沉井水下抗分散混凝土施工关键技术  

Key Construction Technology of Underwater Anti⁃dispersion Concrete for the Open Caisson of Changtai Yangtze River Bridge

作　　者：韩鹏鹏 仇正中[2] 张磊 吴启和 HAN Pengpeng;QIU Zhengzhong;ZHANG Lei;WU Qihe(CCCC Second Harbor Engineering Co.,Ltd.,Wuhan,Hubei 430040,China;Key Laboratory of Large-span Bridge Construction Technology,Wuhan,Hubei 430040,China;CCCC Highway Bridges National Engineering Research Centre Co.,Ltd.,Wuhan,Hubei 430040,China;Research and Development Center of Transport Industry of Intelligent Manufacturing Technologies of Transport Infrastructure,Wuhan,Hubei 430040,China)

机构地区：[1]中交第二航务工程局有限公司,湖北武汉430040 [2]长大桥梁建设施工技术交通行业重点实验室,湖北武汉430040 [3]中交公路长大桥建设国家工程研究中心有限公司,湖北武汉430040 [4]交通运输行业交通基础设施智能制造技术研发中心,湖北武汉430040

出　　处：《施工技术（中英文）》2023年第18期84-89,共6页Construction Technology

基　　金：中交集团课题:120年寿命700m级平行钢丝斜拉索体系及建养关键技术研究(2020⁃ZJKJ⁃03)。

摘　　要：常泰长江大桥主航道桥为双层斜拉桥,其中主跨为1176m,主墩采用台阶式沉井基础。针对沉井隔舱内部复杂结构,研究砂率、水胶比、粉煤灰掺量、增黏剂等因素对混凝土性能影响,通过对混凝土流动性、抗压强度试验、收缩检测分析,得到水下抗分散自密实混凝土最优配合比。结合现场施工条件,提出抗分散混凝土水下封舱施工工艺,解决水下自密实混凝土离析问题。研究结果表明,当水胶比和胶凝材料增加时,自密实混凝土流动性得到明显改善,混凝土抗压强度有所降低。当水泥掺量为312kg/m^(3),粉煤灰为138kg/m^(3),增黏剂为10kg/m^(3),砂为860kg/m^(3),碎石为860kg/m^(3),水为175kg/m^(3),减水剂为4.4kg/m^(3)时,水下自密实抗分散混凝土具有良好工作性能,在沉井隔舱内进行抗分散混凝土水下封舱施工后质量能达到设计标准。Changtai Yangtze River Bridge is a double⁃layer cable⁃stayed bridge,whose main span is 1176m.The main pier adopts a stepped open caisson foundation.Due to the complex structure in the open caisson compartment,This paper studies the effects of the factors such as sand ratio,water cement ratio,fly ash content,and tackifier on the performance of concrete.Though analyzing the fluidity,compressive strength test,and shrinkage detection of concrete,the optimal mix proportion of underwater anti⁃dispersion self⁃compacting concrete is obtained.Based on on⁃site construction conditions,this paper proposes a construction process for underwater anti⁃dispersion concrete sealing to solve the problem of segregation of underwater self⁃compacting concrete.The result show that as the water⁃cement ratio and cementitious materials increase,the flowability of self⁃compacting concrete is significantly improved,and the compressive strength of concrete is reduced.When cement mixing amount is 312kg/m^(3),water mixing amount is 175kg/m^(3),macadam mixing amount is 860kg/m^(3),sand mixing amount is 860kg/m^(3),fly ash mixing amount mixing amount is 138kg/m^(3),tackifier mixing amount is 10kg/m^(3),water reducer mixing amount is 4.4kg/m^(3),underwater self⁃compacting anti⁃dispersion concrete has good working performance,and the quality of anti⁃dispersion concrete after underwater sealing construction in the open caisson compartment can meet the design standards.

关 键 词：桥梁工程 沉井 自密实混凝土 抗分散 抗压强度 密实度 施工技术 

分 类 号：U445.55[建筑科学—桥梁与隧道工程]