Study On Ground Vibration Generated By High-Speed Train Using The Hybrid Model Of Analytic Model And Wavenumber Finite Element Model

On the basis of completely summing up previous research results, combined with the advantage of the wavenumber finite element method and analytic method, the track-embankment-ground system model was established. The impacts of rigidities of track components on track integral stiffness are discussed. Exploring the factors influencing the critical speed of the ballastless track. A preliminary study on the track response under the influence of harmonic irregularity is carried out.The main contents include:1.The ballastless track stiffness has different dynamic characteristic in the low frequency and high frequency ranges. There are multiple peak values and trough values caused by resonance in the low frequency range(0~the third peak frequency of dynamic stiffness). Track stiffness decreased with the increase of frequency in the high frequency range(the third peak frequency of dynamic stiffness~100 Hz).2.Among track components, fastener rigidity have the most significant impact on track stiffness, but have little influence on the resonance frequency in the low frequency range. The elastic modules of the bottom layer of subgrade and ground only have influences on track stiffness in the low frequency range, and with the increasing of the elastic modules, the track resonance frequencies become larger and the static stiffness of track increase, but the maximum dynamic stiffness of track change little. The elastic modulus of surface subgrade and CA mortar have limit impact on the track stiffness.3.Track stiffness and elastic modulus of each component were positively correlated. The maximum dynamic stiffness and fastener stiffness are related, negatively related to the elastic modulus and the foundation, the bottom layer of the bedding and bedding. The fastener stiffness of track static stiffness and dynamic stiffness is the most significant effect, the bedding bottom layer affected by elastic modulus.4.The effect of single point moving load on the rail vertical displacement amplitude with the increase of the speed of movement of the force and slightly increased, when the force moving speed reaches a certain critical value rail vertical displacement with the increase of the speed of movement of the force decreased rapidly. The critical velocity is the critical velocity of the track subgrade earth system, which is determined by the characteristics of the track, subgrade and earth system. In one or two and three, the case, the critical speed of the ballasted track- earth system were 140m/s, 80m/s and 100m/s.5.Earth soil is weak, the vibration response is bigger and the lower cutoff frequency.With the increase in the rate of and the soft earth will be caused by fluctuations in the greaterthe maximum displacement amplitudes, and caused a greater range of vibration in the direction of the train.6.Multiple moving constant loads have multiple critical speed: Earth system before two critical speed for 73m/s, 143m/s; 2nd earth system before three critical speed of 80 m, 175m/s;number three on the earth system before three critical speed for 83m/s, 170m/s ballastless track subgrade earth system. The earth, but in the speed more than second order critical speed rail displacement response amplitude decreased, and earth No.2 and No.3 of the earth rail maximum displacement amplitudes are beyond the second order critical speed are with more force movement speed increase.7.the vibration acceleration of track ballast-ground system from top to bottom gradually decreases. Among ballast track structure of ballast-earth system, at the train speed is 200km/h,the target value of track harmonic irregularity is 6mm, the half wavelength is 10 m, the maximum displacement of rail, ballast surface of the center line, the earth surface center line reached 3.9、0.9 and 0.70m/s2.