Track and ground vibrations generated by high-speed train running on ballastless railway with excitation of vertical track irregularities

• 2.5D FE and thin-layer element are used for modeling infinite track and soils.
• Train–track–soil model is validated by field measurements.
• Both track and soil׳s properties affect ballastless railway׳s critical velocity.
• Ground vibrations are dominated by track irregularities for low-speed trains.
• Ground vibrations are dominated by wheel axle weights for high-speed trains.

Track irregularities generated during the running service of high-speed railways aggravate vibrations of the track and the surrounding ground environment. To better understand the propagation of vibrations induced by high-speed train running on irregular tracks, a 2.5-dimensional (2.5D) finite element model combining with thin-layer elements was applied to establish a vehicle–track–foundation coupled dynamic analysis model. A quarter-car model was used to derive the equation for wheel–rail interaction force considering track irregularity. The track structure and the underlying foundation were simulated using the 2.5D finite element model, and the subsoil boundary was simulated using thin-layer elements. Compared with the field measurements of the Beijing–Shanghai high-speed railway, the reliability of the established numerical model in analyzing vibration response was verified. A spectrum analysis of the response data obtained from the field measurements reveals that for a newly constructed high-speed railway, track alignment is in good condition due to the operation of grinding and leveling, and vehicle parameters dominate the vibration response of the track structure. Then influences of track irregularities of four typical wavelengths on the vibrations of the track and the surrounding ground environment were investigated. It is found that track irregularities of smaller wavelengths induce higher vibration frequencies and significantly higher vibration responses from the track and the ground compared to track irregularities of longer wavelengths. However, the low-frequency vibrations induced by the latter propagate to a longer distance compared to the former. The critical velocity of the ballastless slab track–ground system is greater than the Rayleigh wave velocity of the soft layer of the subsoil. When train speed is lower than the critical velocity, track irregularity substantially affects the vibrations of the track and the surrounding ground. When the train speed exceeds that critical velocity, the ground vibration is determined by the train wheel weight.