Analysis On Seismic Impact Effect And Control Of High-Speed Railway Turnout Beam Under Beam-Rail Interaction

As a transition structure connecting standard simply supported beam and elevated platform in high-speed rail line,switch beam of high-speed rail has different displacement response to earthquake with standard simply supported beam on both sides due to its own quality,stiffness and other characteristics.It is easy to collide at beam joints and cause beam body damage or beam falling disaster.At the same time,the collision response of turnout beam is more complicated because of the special structure of double line to multiple line and the influence of beam and rail interaction.In order to grasp the collision law of switch beam and adjacent beam under earthquake,this thesis takes a high-speed railway(31.85+2×32.7+31.85)m switch beam and its adjacent 32 m simple supported beam as the research object,and conducts correlation analysis and research on the seismic collision response of highspeed rail switch beam under beam and rail interaction.The main work is as follows:(1)Establish scientific and reasonable finite element models of the full bridge without track constraints and with track constraints in consideration and conduct time-history analysis.By comparing the difference of dynamic characteristics of the two models under the same conditions and the difference of collision response under the same seismic wave,the influence law of beam and rail interaction on the collision response of turnout beams is obtained.The analysis results show that: The longitudinal constraints of track on beams can enhance the longitudinal connection between beams,improve the integrity of the bridge,and significantly reduce the collision response between beams.(2)The full bridge finite element model established considering beam-rail interaction was used to analyze the influence of factors such as the space between expansion joints,pier stiffness and longitudinal bridge Angle of the line on the collision response between beams.By comparing the difference of the collision response of the model when the parameters of the same influencing factor changed,the influence law of different influencing factors on the collision response of turnout beams was obtained.The analysis results showed that: The seismic impact response between beams is affected by many factors.By setting the structural parameters of turnout beams reasonably,the impact response between beams can be reduced to a certain extent and the beam damage caused by seismic impact can be reduced.(3)The friction pendulum bearing is set in the switch beam model to analyze the effect of the friction pendulum bearing on the vibration isolation of the switch beam.For the switch beam model considering the beam-rail interaction,the influence of the arrangement of the friction pendulum bearing,the radius of sliding spherical curvature,the friction coefficient between the sliding block and the lower support plate on the vibration isolation effect is studied.The main conclusions are as follows:The friction pendulum bearing can effectively reduce the seismic impact response of the switch beam,and reasonable parameters should be selected to achieve better vibration reduction and isolation effect.