Analysis Of Vertical Vibration Characteristics Of Ballasted Track With Elastic Sleepers In Elevated Station

With the rapid development of the railway industry,people have stricter requirements on the smoothness,stability and durability of the tracks,especially ballasted tracks on rigid foundations such as bridges,tunnels and culverts.The overall rigidity of the track is too large and the track structure is not elastic enough,which will affect the safety and stability of the train operation,at the same time,it will increase the dynamic response of the track structure itself and the structure such as bridge and tunnel culvert.Bridge type elevated station as a station form combining bridges and buildings,also facing vibration response due to excessive track stiffness.Therefore,in order to reduce the adverse impact on the track structure and the infrastructure of the station when the non-stop train passes,measures need to be taken to improve.In order to find out the applicability and damping performance of elastic sleepers laid on ballasted track in elevated stations,this paper fully studies the previous studies based on dynamic theory and finite element method.For more real and effective simulation analysis of the vertical vibration of elastic sleeper ballasted track in elevated station,a large finite element software is applied ABAQUS and a dynamic model of vehicle-ballast track-highway station space coupling is established.The influence of elastic sleepers and ordinary concrete sleepers on the vertical dynamic response of vehicles,tracks,box beams and platform beams is analyzed.The reasonable range of stiffness of cushion under pillow and the vertical vibration characteristics of elevated stations under different driving speeds are studied.After analysis and research,the main conclusions are as follows:(1)Laying elastic sleepers can ensure the stability and safety of train operation in elevated stations,and some vehicle dynamic indicators can be improved.(2)During the running of the train,the laying of elastic pads under the sleepers will cause a significant increase in the vertical displacement of the rails and sleepers.But at the same time,the vibration acceleration and top surface compressive stress of the ballast bed can be greatly reduced.(3)The setting of elastic cushion under pillow also improves vertical displacement and vertical acceleration of box girder structure in elevated station.(4)Compared with the common ballast track,the elastic sleeper has a good damping effect,and the elastic sleeper is laid in the elevated station,which can reduce the time and frequency domain of the platform structure.The vertical displacement of platform is reduced by 13.3%,the vertical acceleration of platform is reduced by 13.7%,and the damping effect of platform beam is 3?6 dB in 6.3?100 Hz frequency band.(5)From the aspects of controlling the vibration and displacement of the track structure and ensuring the vibration absorption effect of the elevated station,it is suggested that the reasonable stiffness range of the elastic cushion should be 40?60 kN/mm.(6)When the stiffness of the elastic pad under the rail is reasonable,and the laying of elastic sleepers has the effect of reducing the vibration of the structures of the elevated station when the trains with different speeds pass through the elevated station.