滨海强腐蚀环境高速铁路桥梁混凝土结构耐久性设计研究

Durability Design and Research on High-speed Railway Bridge Concrete Structure in Coastal Environment with Strong Corrosion

石衡沧港城际铁路工程滨海盐田区域为强腐蚀性环境,为保证桥梁结构的长期运营安全,开展相关的耐久性研究,提高桥梁结构耐久性是本工程亟待解决的问题。通过详细调研和分析该区域内桥梁工程的侵蚀性环境特点,对桥梁结构的暴露环境进行评定,开展桥梁混凝土结构耐久性设计研究,形成如下研究成果。针对铁路工程面临的侵蚀性环境问题,提出了总体设计方案原则;对滨海强腐蚀环境桥梁桥墩承台和灌注桩高耐久混凝土进行配合比设计,形成适用于滨海盐田强腐蚀环境高耐久性混凝土的制备技术;研究耐久性构造设计,提出构造设计原则及物理隔绝设计理念,提出提高耐久性结构设计控制措施,进行结构物理隔绝措施设计,有效地提高桥梁结构的耐久性;针对本工程侵蚀性特点提出硅烷浸渍防护及耐蚀钢筋附加强化防护措施;研究和应用了透水模板布,提高混凝土的施工质量和密实性;在工程现场建立暴露试验站,开发钢筋混凝土耐久性无线监测系统,实现钢筋锈蚀全过程监测。通过滨海强腐蚀环境桥梁混凝土结构耐久性设计研究,达到滨海盐田严酷服役条件下铁路工程混凝土结构耐久性提升的目的,同时为服役期桥梁结构耐久性后期评估打下坚实的基础。

The coastal salt pan of Shijiazhuang-Hengshui-Cangzhou-Huanghua Port Intercity Railway project is a highly corrosive environment.In order to ensure the long-term operation safety of the bridge structure,it is urgent to carry out relevant durability research and improve the durability of the bridge structure in this project.Through detailed investigation and analysis of the erosive environmental characteristics of the bridge engineering in this region,the exposed environment of the bridge structure is evaluated,durability design of the bridge concrete structure is carried out,and the following research results are presented.In view of the corrosive environment problems faced by railway engineering,the principle of overall design scheme is proposed.The mix ratio design of bridge pier pile-cap and castin-place pile in coastal corrosive environment is conducted,and the preparation technology of high durability concrete suitable for coastal salt pan corrosive environment is formed.The structural design of durability is studied,structural design principle and physical isolation design concept are proposed,the structural design control measures are proposed to improve durability,and the structural physical isolation measures are designed to effectively improve the durability of bridge structure.In view of the erosion characteristics of the project,additional strengthened protection measures are put forward,including the silane impregnation protection and the application of corrosion resistant reinforcement.The permeable formwork cloth is studied and applied to improve the construction quality and compaction of concrete.An exposure test station is set up in the engineering site and a wireless monitoring system for reinforced concrete durability is developed.The whole process of reinforcement corrosion monitoring is realized through the wireless monitoring system.Through the durability design and research of concrete structure of bridge in the coastal environment with strong corrosion,the purpose of improving the durability of railway concrete structure under the harsh service condition of coastal salt pan has been achieved.At the same time,The solid foundation has been laid for the later evaluation of the durability of the bridge structure during the service period.