Vibration characteristics and transmission law of turnout with combined vibration reduction measures in metro depot

The vibration problem caused by the frequent operation of trains in the metro depot seriously affects the living comfort of the over-track building. However, since the track in the depot is mainly composed of ballasted track turnouts, the low frequency shock vibration caused by the geometrical irregularity deterioration of the ballast bed system itself and the stiffness irregularity of each part of the turnout has become one of the key technical difficulties in the vibration control of the metro depot. To solve the above problems, the combined vibration reduction scheme of ballast-protected elastic sleepers and vibration-damping ballast mats was proposed and applied to a depot. In order to clarify the vibration characteristics and transmission law of ballast bed in turnout section of test line under the combined vibration reduction scheme of ballast-protected elastic sleeper and vibration-damping ballast mat. Taking a metro depot in Xi’an with combined vibration reduction as an example, the field measurement and analysis were carried out. The validity of the test data was verified by the repeatability in the frequency domain. On this basis, time domain, frequency domain, maximum Z level and transmission loss analyses were carried out on the rails, sleepers and ground measurement points in the three sections of the turnout into section, center section and out section. In addition, the vibration reduction amount and working frequency band of the combined vibration reduction measures were determined by analogy analysis with the non-vibration reduction depot. The results are drawn as follows. Compared with the test results of other metro depot without vibration reduction measures, the maximum vibration reduction effect of the combined vibration reduction measures reaches 17.9 dB on the maximum Z vibration level index. In addition, the working frequency band of the combined vibration reduction measures is 5～315 Hz on the 1/3 octave. The vibration level of rail and sleeper is equivalent, which shows that improving the stiffness of fastener and using under sleeper pad to form an integrated design of rail and sleeper has obvious effect. The vibration level of the turnout center is greater than that of the into and out sections. The main frequency of the ground vertical vibration caused by the turnout center and the out is 12.5～125 Hz, and the increase of the Z vibration level of the into section is more significant with the increase of the train speed. © 2024, Central South University Press. All rights reserved.