IN-SITU MEASUREMENTS AND STUDY OF TRAIN INDUCED GROUND VIBRATION

摘要

This paper reports on the in situ measurements of train induced ground vibration on the Metro Line 5 in Beijing.The mitigation measures taken into consideration are the ordinary simple fastener (DTVI2 fastener),Vanguard fastener and floating slab track (FST for short).In this paper,through the measurement setup and data analysis procedures,the comparison of the measurements to different mitigation measures are discussed elaborately from frequency contents to RMS one-third octave band spectra.And the characteristics of different mitigation measures propagation along the direction away from the metro line are reviewed.From the measurement and analysis,following results are obvious: (1) Vanguard fastener and FST have a much better function of vibration absorption than that of DTVI2 fastener.The maximum mitigation value are 18 dB VAL for Vanguards fastener,and 25 dB VAL for FST; (2) 50～ 80 Hz frequency zone is the dominant frequency from the view of ground response for the three mitigation measures.Particularly,30 Hz for Vanguard fastener and 10 Hz for FST,over these working frequencies,better effects in mitigation can be gained; (3) Different line status influences the ground vibration level and circle curve lines amplify the adverse vibration effects,and the ground-borne vibration decrease away from distance of metro line,while a vibration amplifying area occurs on the ground surface in a certain distance; (4) The adoptions of Vanguard fastener and FST satisfy the environmental standard values of vibration in these areas along the metro.