Study On Vibration Reduction Of Rubber Floating Slab Track In High Speed Railway

With the rapid development of high-speed railway and urban rail transit in China,the problem of vibration and noise become more and more serious.When the train passes through,the vibration is transmitted to the base from the track structure,and then transferred from the lower part to the surrounding environment.In the aspect of urban rail transit,in order to solve the problem of environmental vibration caused by train,the floating slab track has been designed and the effect of vibration reduction has been achieved.In the aspect of high speed railway,the application of floating slab track has been gradually applied in our country.However,the research on the safety and vibration reduction effect of floating slab in high speed railway is not enough.Aiming at the problem of high speed railway with rubber floating slab,high-speed train-floating slab-foundation model is established.The paper is systematically studied from the aspects of track structure parameters,vibration response distribution characteristics,which can provide a reference for the vibration reduction of high speed railway floating slab track.The main points are as follows:1.Based on the finite element method,a floating slab track-foundation finite element model was established,the rail is simplified as a beam element,the fastener is simplified as a spring damper element,slab track,self-compacting concrete,rubber plate,base plate and foundation are simulated by solid elements.Based on the theory of multi-body dynamics,a high speed train model is established,and the coupling model of train and floating slab track foundation is coupled by the vehicle track coupling method.2.Through the established high-speed train and floating slab track based coupling dynamic analysis model,the effect of systematic parameter was analyzed,including the damping pad laying type,rubber mat stiffness,track slab thickness and track slab length.According to the analysis results of the harmonic response and the vehicle track coupling,the vibration of the rail,the track plate and the bottom plate reduced gradually.Compared with the length and thickness of the track slab,the influence of the type of the rubber mat and the stiffness of the damping pad is greater,and the two results are in good agreement.For the floating slab track on the sub grade,the decrease of the damping pad area and the decrease of the stiffness make the natural frequency of the system decrease gradually,which can significantly reduce the high frequency vibration of the sub grade.At the same time,it will lead to a significant increase in rail deformation and the wheel rail force,which may bring adverse effects on driving safety.Therefore,taking into account the safety of driving,vibration pad stiffness should not be too small.3.Using the high-speed train and floating slab track based coupling dynamic analysis model,by comparative analysis of a large number of reference points of dynamic response of track and subgrade vibration,the paper studied the vertical and horizontal distribution of vibration.The vertical distribution characteristics of vibration are as follows:for the floating slab track,from the self-compacting concrete to the base plate,the acceleration value decreases sharply,and the acceleration value of the common rail self-compacting concrete and the base plate is not big.Different positions of the subgrade from low to deep,acceleration decrease slowly.The distribution of subgrade cross section is larger than that of the track,and the acceleration value is smaller.The acceleration value of the structure above the damping pad is larger,and the acceleration value of the following structure is consistent.The horizontal distribution characteristics of vibration are as follows:ordinary track plate acceleration maximum values appeared in the fastener position,floating slab track plate vibration and the maximum acceleration is not necessarily the maximum fastener position,may also be in the plate end position.The vibration of the track plate increases as a result of laying the damping pad.The maximum acceleration of the top surface of the subgrade usually appears at both ends of the base plate.The limit of acceleration distribution on the top of the subgrade is not as obvious as that of the common rail,and the acceleration of the top surface of the subgrade is smaller.