高速列车荷载与环境因素耦合作用下桥上CRTSⅢ型板式无砟轨道结构耐久性劣化行为研究

高铁运营实践表明，在列车荷载、温度、侵蚀介质等多因素长期耦合作用下轨道结构会发生损伤劣化现象，长期累积势必将影响轨道结构耐久性和运营品质，甚至危及行车安全。由于我国自主研发的CRTSⅢ型板式无砟轨道结构研究和应用时间还比较短，目前尚缺乏系统深入研究多因素耦合作用下服役无砟轨道结构耐久性劣化机理和行为。为此，本项目拟围绕CRTSⅢ型板式无砟轨道结构水分迁移-腐蚀介质传输-钢筋锈蚀耐久性劣化过程，基于多场耦合理论和电化学动力学研究疲劳损伤混凝土和离缝界面的介质传输和钢筋锈蚀本构模型，基于理论和数值方法研究自然环境条件下CRTSⅢ型板式无砟轨道结构湿度场、荷载与环境因素耦合作用下CRTSⅢ型板式无砟轨道结构介质传输和钢筋锈蚀行为，进而从材料-部件-结构层面深入揭示列车荷载与环境因素耦合作用下CRTSⅢ型板式无砟轨道结构耐久性劣化机理和行为。研究成果将为轨道结构的设计、评估和养护维修提供科学依据。

The operation practices of high-speed railway at home and abroad show that the ballastless track structures are deteriorated due to multi-factor long-term coupling effects of high-speed train load, temperature and aggressive medium. The long-time accumulated effect of ballastless track structure is bound to affect durability of track structure and operation quality of high-speed train, and even endangers traffic safety. Since research and application time on the new self-developed CRTSⅢ slab ballastless track structure is relatively short, there is still lack of systematic and in-depth research on the durability deterioration mechanism and behavior of the existing ballastless track structure under multi-factor coupling. The project is planned to focus on the durability degradation whole process of water transfer, aggressive medium transmission, and steel bars corrosion of CRTSⅢ slab ballastless track structure. Based on the multi-field coupling method and electrochemical kinetics, the constitutive model of medium transport and steel corrosion of fatigue damage concrete and crack interface are systematically investigated. Based on theoretical analysis and numerical simulation, the humidity field of CRTSⅢ slab ballastless track structure under natural environment, the medium transport behavior of track structure under the coupling action of load and environmen, and steel corrosion behavior of track structure under the coupling action of load and aggressive medium are systematically investigated. The durability deterioration mechanism and behavior of CRTSⅢ slab ballastless track structure under the coupling effect of high-speed train load and environmen will be revealed from material, component and structure level. The results will provide important science basis for design, evaluation and maintenance of slab ballastless track structure.