高铁桥梁全封闭声屏障降噪性能试验与数值研究

Experimental and Numerical Research on Noise Reduction Performance of Fully Enclosed Sound Barriers on High-speed Railway Bridges

为探明铁路桥上全封闭声屏障的降噪性,选取铁路桥上不同车速的混凝土全封闭声屏障、金属全封闭声屏障和单侧直立式声屏障测试断面,开展声屏障内外声场的噪声测试,建立全封闭声屏障统计能量分析模型,结合实测结果验证数值模型的适用性,最后对比分析声屏障不同结构形式、隔声板材料和传声损失、车速对声屏障降噪量的影响,探讨声屏障数值模型中的传声损失、模态密度参数对外声场的影响。研究结果表明:在测试车速下,声屏障内部噪声显示出轮轨噪声频谱特性,空间分布符合线声源的衰减特性;采用所建立的全封闭声屏障统计能量分析模型来预测声屏障外部噪声的A声级与实测结果具有良好的一致性;与直立式声屏障相比,全封闭声屏障的插入损失高9dB(A)以上,并随列车速度的增大而增大,全封闭声屏障对高频噪声成分的降噪效果更优;提高声屏障隔声板的传声损失导致外声场噪声的衰减量,略大于同幅度降低传声损失导致的噪声增加量;声屏障统计能量分析模型中隔声板的模态密度对声屏障降噪性能的影响比内声腔的模态密度敏感。

To explore the noise reduction performance of a fully enclosed sound barrier(FESB)on railway bridges,this study carried out systematic field noise tests on typical sections of concrete FESB,metal FESB,and unilateral vertical sound barriers on railway bridges;established a statistical energy analysis(SEA)model of the barrier;and verified the model using measured results.The influence of structures,materials,train speeds,transmission loss,and mode densities of the barriers on noise reduction was analyzed,and the effects of transmission loss and modal density parameters on the external sound field of FESBs were discussed.Results show that the noise measured inside barriers by field tests could indicate the spectrum characteristics of wheel/rail noise.The spatial distribution conforms to the attenuation characteristics of the line source.The SEA model predicts that the external noise of the FESBs will agree well with the measured results.The insertion loss of the FESB is 9 dB(A)larger than that of the vertical sound barrier,and the noise mitigation of the FESB is better,especially for the high-frequency noise components.External noise attenuation caused by the increase in transmission loss is slightly larger than the increase in the noise caused by the same decrease in the transmission loss.Finally,it was determined that the influence of the insulation panel’s mode densities on the FESB’s noise attenuation is more sensitive than that of the inner cavity densities.