The pseudo-excitation method combined with the integral transform method (PEM-ITM) is presented to investigate the ground vibration of a coupled track-soil system induced by moving random loads. Commonly in the track ...The pseudo-excitation method combined with the integral transform method (PEM-ITM) is presented to investigate the ground vibration of a coupled track-soil system induced by moving random loads. Commonly in the track model, the rail, sleepers, rail pads, and ballast are modelled as an infinite Euler beam, discretely distributed masses, discretely distributed vertical springs, and a viscoelastic layer, respectively. The soil is regarded as a homogenous isotropic half-space coupled with the track using the boundary condition at the surface of the ground. By introducing a pseudo-excitation, the random vibration analysis of the coupled system is converted into a harmonic analysis. The analytical form of evolutionary power spectral density responses of the simplified coupled track-soil system under a random moving load is derived in the frequency/wavenumber domain by PEM-ITM. In the numerical examples, the effects of different parameters, such as the moving speed, the soil properties, and the coherence of moving loads, on the ground response are investigated.展开更多
The dynamic behaviour of slab and ballast tracks was investigated using measurements and calculations.Hammer impacts and train passages were analysed and measurements were made using geophones(velocity transducers)whi...The dynamic behaviour of slab and ballast tracks was investigated using measurements and calculations.Hammer impacts and train passages were analysed and measurements were made using geophones(velocity transducers)which had been time-integrated to displacements.The calculations were carried out in the frequency-wavenumber domain for multi-beamon-continuous soil models.The characteristics of the different tracks and track elements were established in theory and by experiment.The frequency-dependent compliances(displacement transfer functions)showed clear rail-on-railpad resonances or highly damped track-soil resonances.Compared to the rail and sleeper,the track slab had much lower amplitudes.The slab track usually had the highest rail amplitudes due to soft railpads.Train passage yielded track displacements which were a superposition of the axle loads from the two neighbouring axles of a bogie and from the two bogies of two neighbouring carriages.This global behaviour was characteristic of the track slab of the slab track,whereas the rails of the slab and the ballast tracks behaved more locally with only one bogie of influence.The measurements agreed very well with the theory of continuous soil in the case of the six measured slab tracks and acceptably well for the six measured ballast tracks.The measurements allowed us to find appropriate model parameters and to check the models.For example,the Winkler model of the soil was found to be less appropriate because it reacted more locally.展开更多
基金the National Basic Research Program of China (Grant 2014CB046803)the National Natural Science Foundation of China (Grant 11772084).
文摘The pseudo-excitation method combined with the integral transform method (PEM-ITM) is presented to investigate the ground vibration of a coupled track-soil system induced by moving random loads. Commonly in the track model, the rail, sleepers, rail pads, and ballast are modelled as an infinite Euler beam, discretely distributed masses, discretely distributed vertical springs, and a viscoelastic layer, respectively. The soil is regarded as a homogenous isotropic half-space coupled with the track using the boundary condition at the surface of the ground. By introducing a pseudo-excitation, the random vibration analysis of the coupled system is converted into a harmonic analysis. The analytical form of evolutionary power spectral density responses of the simplified coupled track-soil system under a random moving load is derived in the frequency/wavenumber domain by PEM-ITM. In the numerical examples, the effects of different parameters, such as the moving speed, the soil properties, and the coherence of moving loads, on the ground response are investigated.
文摘The dynamic behaviour of slab and ballast tracks was investigated using measurements and calculations.Hammer impacts and train passages were analysed and measurements were made using geophones(velocity transducers)which had been time-integrated to displacements.The calculations were carried out in the frequency-wavenumber domain for multi-beamon-continuous soil models.The characteristics of the different tracks and track elements were established in theory and by experiment.The frequency-dependent compliances(displacement transfer functions)showed clear rail-on-railpad resonances or highly damped track-soil resonances.Compared to the rail and sleeper,the track slab had much lower amplitudes.The slab track usually had the highest rail amplitudes due to soft railpads.Train passage yielded track displacements which were a superposition of the axle loads from the two neighbouring axles of a bogie and from the two bogies of two neighbouring carriages.This global behaviour was characteristic of the track slab of the slab track,whereas the rails of the slab and the ballast tracks behaved more locally with only one bogie of influence.The measurements agreed very well with the theory of continuous soil in the case of the six measured slab tracks and acceptably well for the six measured ballast tracks.The measurements allowed us to find appropriate model parameters and to check the models.For example,the Winkler model of the soil was found to be less appropriate because it reacted more locally.
基金Project(51878670) supported by the National Natural Science Foundation of ChinaProject(GJJ204 611) supported by the Science and Technology Research Program of Education Department of Jiangxi Province,China。
基金Project(52078498)supported by the National Natural Science Foundation of ChinaProject(2021-Special-04-2)supported by the Science and Technology Research and Development Program Project of China Railway Group Limited+2 种基金Project(2022JJ30745)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2023QYJC006)supported by the Frontier Cross Research Project of Central South University,ChinaProject(2020TJQ19)supported by the Hunan Provincial Science and Technology Promotion Talent Project,China。
