Experimental investigation of the vibration-attenuating effect of rail suspension fasteners on environment vibration induced by subway

Abstract

A field test of environment vibration due to subway was carried out so as to investigate the vibration-alleviating effect of rail suspension fasteners in both time and frequency domains. The experimental results show that the time-domain vertical ground vibration accelerations would transform from several concentrated vibrations to the decentralized and uniform ones after replacement of common rail fasteners with rail suspension fasteners. Moreover, rail suspension fasteners have more significant vibration-mitigation effect on the time-domain peak particle accelerations (PPAs) at the nearer positions than at the farther ones, and the minimum PPA induced by common rail fasteners is still higher than the maximal PPA caused by rail suspension fasteners at all measuring positions. In frequency domain, the vibration-reduction effect of rail suspension fasteners is more remarkable in the dominant 1/3 octave center frequencies of 50-125 Hz than in the non-dominant ones from 1 to 40 Hz. Compared with common rail fasteners, the highest vibration acceleration levels (VALmax) in the dominant 1/3 octave center frequencies between 50 and 125 Hz at all measuring positions decrease by 8.7-21 dB after adoption of rail suspension fasteners. Additionally, the integrated VLzs in 1/3 octave center frequencies of 1-125 Hz at all measuring positions are ranged from 77.1 dB to 66.5 dB, evidently higher than the China’ standard threshold of 65 dB, before replacement of common rail fasteners, while the integrated VLzs are framed between 68.3 and 57.3 dB, mostly less than the threshold, after application of rail suspension fasteners.