大跨斜拉钢桁梁桥上无砟轨道纵向约束参数优化研究OA

The application of ballastless track on a long-span cable-stayed steel truss bridge is limited,and the longitudinal constraint parameters between the girder and rail on a long-span cable-stayed steel truss bridge directly affect the stress and deformation of the ballastless track.In order to explore the beam-rail interaction pattern of ballastless track on a long-span cable-stayed steel truss bridge and improve the longitudinal stress state of the structure,a long-span cable-stayed steel truss bridge with a main span of 392 m for a high-speed railway was taken as the research object.Based on the finite element method,a refined model of beam-rail longitudinal interaction on the bridge was established.The effects of different temperatures and train loads were considered,and the influence of parameters such as the longitudinal groove pad stiffness and the longitudinal resistance of fasteners on the stress and deformation of the ballastless track structure was analyzed,and the reasonable values of longitudinal constraint parameters were discussed.The research showed that:(1)the temperature load was the main controlling load of the longitudinal force of the rail within the main girder span,and the deflection and braking load affected the longitudinal force of the rail to a small extent in the loading range.(2)When the pad stiffness changed,the longitudinal force of the rail changed by less than 0.05%.It was considered that the longitudinal groove pad stiffness had no effect on the longitudinal force of the rail.(3)When the groove pad stiffness was reduced,the longitudinal force of the groove decreased,and the compression of the elastic pad increased.When the stiffness was reduced to 75 kN/mm,the compression of the pad reached 1.37 mm,which exceeded the allowable deformation,and there was a risk of damage.Further increasing the pad stiffness on the basis of the original stiffness was unfavorable to its long-term performance.(4)Compared with the conventional resistance fastener,the small-resistance fastener reduced the groove force by about 19.8%,and reduced the maximum compression deformation of the pad by about 21.1%.It was suggested that the small-resistance fastener should be installed within 50 m of the main bridge ends,and the pad stiffness should be 200 kN/mm,which could reduce the influence of beam-rail interaction.