铁路无砟轨道吸声板降噪效果分析

Analysis on the Noise Reduction Effect of the Sound Absorption Panels for Railway Ballastless Track

铁路无砟轨道区段的噪声辐射比有砟轨道区段严重,常采用轨道表面铺设吸声板来降低轮轨噪声对周边环境的影响。为了控制铁路无砟轨道区段的轮轨噪声辐射,根据微穿孔板吸声理论建立多孔吸声板吸声系数计算模型,并将计算得到的吸声系数输入到轮轨噪声预测系统中,得出轨旁噪声的频谱和等效声级,分析多孔吸声板的空隙率、厚度和孔径对降低轮轨噪声的影响规律。研究结果表明:多孔吸声板的空隙率越大,对轮轨噪声的吸声效果越好,但太大的空隙率会降低对中高频轮轨噪声的吸收,建议空隙率应该控制在0.4%～0.6%之间为宜;多孔吸声板厚度越大,对轮轨噪声的吸声效果越好,但板厚过大会影响到其他行车安全问题,板厚应控制在既能高效降低噪声、又能保证行车安全的限值之内;多孔吸声板的孔径越大,对轮轨噪声吸声效果越差。

The noise radiation of railway ballastless track is more severe than that of the ballast track.The common way to reduce the impact of the wheel/rail noise on the surrounding environment is to lay sound absorption panels on the surface of the ballastless track.In order to control the wheel/rail noise radiation of the railway ballastless track,a model was developed based on the sound absorption theory of micro-perforated panels to calculate the absorption coefficient of the porous sound absorption panels.Then the calculated sound absorption coefficient was input into the wheel/rail noise prediction system to obtain the fre-quency spectrum and equivalent sound level of the wayside noise.The influence laws of the material porosity,the plate thickness and the micro-porous diameters on the reduction effect of the wheel/rail noise were analyzed.The results show that,the greater is the material porosity of the porous sound absorption panel,the better is the wheel/rail noise absorption.However,too much of the material porosity can reduce the sound absorption of the middle and high frequency wheel/rail noise.It is proposed that the material porosity should be controlled within the range of 0.4%～0.6%.The greater is the thickness of the porous sound absorption panels,the better is the wheel/rail noise absorption,but too much of the panels thickness will give rise to other train running safety problems.Accordingly,the thickness of the panel should be controlled under the limit values which can effectively reduce the noise as well as guarantee the running safety. The greater is the micro-porous diameters of the sound absorption panel,the worse is the wheel/rail noise absorption effect.