Experimental Study on Vibration Transmission and Attenuation Characteristics of Ballasted Track under Excitation of Three-sleeper Tamping Machine
Unsteady tamping operation by large machinery is an essential process before the opening of new railways.However,there is no research on the vibration transmission characteristics of ballasted tracks under the excitation of three-sleeper tamping machine.In response to this deficiency,based on a typical newly-built railway,carried out a large-scale in-situ test of the dynamic response of ballasted tracks during tamping operations.In addition,self-made bi-axial acceleration sensors were embedded in different positions inside the granular ballast bed to realize real-time monito-ring of the evolution of internal vibration level.Wavelet analysis and Fast Fourier Transform methods were used to explore the vibration transmission and attenuation characteristics of sleepers and ballast bed during the tamping operation from the perspective of time-frequency domain.At the same time,the vibration absorption capacity and energy dissipation characteristics of the ballasted track under the influence of different times of tamping operations were compared and ana-lyzed.The research results show that the typical reverse vibration transmission in the process of tamping can reduce the bearing capacity and stability of the ballast bed.The main response frequency of the sleeper in the squeezing stage is 68.7 Hz,which is about twice the fixed vibration frequency of the tamping picks at 35 Hz.During the tamping opera-tion,there are significant differences in the sensitivity of the sleeper to vibrations in different directions,with the lateral vibration component of the tamping picks to stimulate a richer vibration response inside the ballast bed.During the third tamping operation,the vibration level of the ballast bed is low,with smallest ballast particle breakage probability.There-fore,it is recommended that when multiple continuous tamping operations are performed on site without changing the tamping operation time and other tamping operation parameters,the number of operations should not exceed 3 times to ensure the best tamping effect.
newly constructed railwaystamping operationvibration transmission mechanismvibration attenuationtamping times
万方数据
维普
