Research On Track-bridge Interaction And Influencing Factors Of High-speed Railway Continuous Steel-truss Arch Bridge

Laying CWR on the bridge can effectively reduce the impact of train on the bridge.At home and abroad,the research on the interaction between beams and rails is mainly about the small and Medium Span Simply Supported Bridges and continuous bridges,less about the long-span continuous steel truss arch bridges,and the interaction between beams and rails of high-speed railway continuous steel truss arch bridges is more complex.Therefore,it is necessary to study the beam rail interaction and its influencing factors of long-span steel bridge.In this paper,the 3 × 168 m continuous steel truss arch bridge of Yinchuan airport Yellow River Bridge of Yinxi high-speed railway is taken as the research object.The finite element model considering the track,the subgrade at both ends of the bridge and the pier and abutment is established by using the finite element software ANSYS.The interaction rule and the influencing factors of the steel truss arch bridge are studied.The main research work is as follows:(1)Based on the basic principle of beam rail interaction,the finite element model of beam rail interaction is established by ANSYS.The main components of steel truss arch bridge,such as main truss member,horizontal and longitudinal joint,arch assistant,suspender,are simulated by beam element,the longitudinal resistance of the line is simulated by nonlinear spring,the beam body is simulated by beam element with rigid arm,the steel rails on the bridge extend 150 m on the subgrade at both ends of the bridge,and the spatial finite element model of continuous steel truss arch bridge is established.(2)Taking the 3 × 168 m continuous steel truss arch bridge of Yinchuan airport Yellow River Super Major Bridge of Yinxi high speed railway as the research object,this paper studies the rail stress distribution,the relative displacement of beam and rail,and the stress on the pier top under the conditions of temperature load,vertical load of train,brake of train and rail fracture,and combines the longitudinal additional stress under the combined conditions The rail strength is calculated.By analyzing the distribution law of rail stress,it is found that the maximum rail expansion stress is the control load.The maximum stress of the rail appears at the right end of the steel truss arch bridge.The horizontal force on the top of the brake pier is the largest.When the rail breaks at different positions,the rail stress is released immediately at the fracture,and the rail stress gradually increases to both sides of the fracture.(3)This paper studies the influence factors of beam rail interaction of long-span continuous steel truss arch bridge,analyzes the weakening effect of two kinds of laying schemes of small resistance fasteners and different positions of rail expansion regulators on the rail stress of continuous steel truss arch bridge,the weakening effect of small resistance fasteners on the rail expansion stress of steel truss arch bridge and the subgrade at both ends of the bridge is more obvious,and the right beam of steel truss arch bridge is more obvious The maximum reduction of compressive stress at the end is 22.7%.(4)This paper analyzes the influence of setting adjuster on the interaction between beam and rail in the steel truss arch bridge.When setting adjuster in the middle of the span,it has a strong release effect on the rail stress in the middle of the span.The maximum compressive stress of the steel truss arch bridge is reduced to 54.1mpa.At the right end of the beam,the maximum compressive stress of the rail is reduced to 5.6mpa by 25.3%.The results show that the rail strength can not meet the requirements only when the small resistance fastener is laid,and the rail expansion regulator can be set at the maximum stress position(right beam end)of the steel truss arch bridge to make the rail strength meet the specification requirements.(5)The change of the longitudinal stiffness of the whole pier top has a certain influence on the rail stress.With the increase of the longitudinal stiffness of the whole pier top,the rail braking stress decreases with the increase of the pier stiffness.Under the right braking condition,when the pier stiffness is taken as 5 times of the original value,the maximum rail compression stress decreases by 34.7%.Only when the longitudinal stiffness of the pier top is changed,the change rule of rail stress is similar to that of the whole pier top,and the change range of rail stress is smaller than that of the whole pier top.