Analysis of Propagation Characteristics and Noise Reduction Measures on Underground Platform from Wheel-Rail Rolling Noise

Abstract:

In order to analyze the sound field distribution of subway underground platform from wheel-rail rolling noise， a three-dimensional full-length acoustic model of platform was established based on the geometric acoustic method. The wheel-rail rolling noise while the train was passing was calculated using the finite element method and boundary element method and it worked as the source of the platform acoustic model. The sound field distribution and propagation characteristics of the platform from wheel-rail rolling noise were studied.Based on which， the noise reduction effect of using sound-absorbing materials was analyzed， including the laying positions and lengths of absorbing materials. The results show that with a train entering， the most notable regions of noise on the platform are at the train-arriving end and 6m away from the platform gate of the passing side in lateral， and the noise is gradually reduced along longitudinal and lateral. The effect of rolling noise on the train-leaving end is small. The noise on the platform is most remarkable when only one train pulls into the station. The A-weighted overall sound pressure level reaches 83.1dB （A）. Besides， the cases that sound-absorbing materials covered both on the vertical wall of the niche under platform and side wall opposite the platform alongside the track area can achieve a good noise reduction effect. The noise reduction at the platform train-arriving end can reach 2.9~5.3dB （A）. Moreover， the noise reduction at the platform train-arriving end can reach 6.1~7.9dB （A） with the sound-absorbing materials laying area extending into the tunnel about 10m， especially when the train is near the platform but still in the tunnel. But the effect will not be improved obviously if the laying length continues to be extended.

Key words:subways;underground platform;wheel-rail noise;sound distribution;noise reduction effect