Analysis of the effect of combined noise reduction measures of trapezoidal sleeper and sound barrier on elevated line

Abstract

In this paper, a noise test on the viaduct of a city in China was conducted to analyze the effect of trapezoidal sleepers, sound barriers, and the combination of trapezoidal sleepers and sound barriers on the spatial distribution characteristics of overall noise. A statistical energy analysis model was established to analyze the influence of these sound barrier configurations. The results show that at the speed of 60 km/h, the trapezoidal sleeper track can reduce the overall noise by 2.0 dB to 6.0 dB. The upright-type sound barrier can reduce the overall noise by 10.3 dB to 13.2 dB, with the most significant frequency band of noise reduction above 800 Hz; the combination of the trapezoidal sleeper and sound barrier has a significant noise reduction effect above 31.5 Hz, and the overall noise reduction can reach 13.8 dB to 23.1 dB. The high-frequency wheel-rail noise decays faster with distance, while the low-frequency bridge structure noise decays slowly with distance. When sound barriers are set up on both sides of the viaduct, the sound pressure level at the near field point is further reduced by 3.3 dB to 5.2 dB compared with sound barriers on only one side. Compared with a section with no sound barriers, the noise inside the sound barriers is about 1.2 dB higher than when the sound barriers are set on one side or both sides of the viaduct.