寒区无砟轨道混凝土冻融-疲劳耦合损伤机理研究综述OA

With the extension of high-speed railways into cold and high-altitude regions,ballastless track concrete structures face severe durability challenges under the long-term coupling action of freeze-thaw cycles and high-frequency train loads.The damage evolution mechanism and research progress of ballastless track concrete under freeze-thaw cycle,fatigue load,and their coupling action were systematically reviewed.Firstly,the cyclic action characteristic of the freeze-thaw cycle was elaborated,and the cross-scale experimental research results of ballastless track concrete were summarized to reveal the damage development law of ballastless track concrete under the freeze-thaw cycle.Furthermore,the statistical characteristics and transfer law of train load were explored.The mechanical properties of the ballastless track concrete structure and the interlayer interface under train load were discussed from the levels of material specimen and full-scale structure tests,and the theoretical analysis framework of ballastless track introducing concrete damage mechanics was generalized.Finally,the synergistic damage effect of freeze-thaw and fatigue coupling action was generalized,and it was pointed out that the coupling action significantly exacerbated the micro-pore development and macro-mechanical property degradation of concrete.The research status and latest progress in this field were reviewed and evaluated,and the existing technical problems in current research and the development trend of future research were clarified to provide theoretical support for the safe operation and maintenance and long-term design of ballastless tracks in cold regions.