V型声屏障隔声性能测试及降噪效果预测

为了评价V型声屏障的降噪效果，通过试验及预测相结合的方法对低载荷V型声屏障进行研究。首先对V型声屏障进行实验室隔声性能测试，结果显示其计权隔声量比直立型声屏障小23.8 dB，隔声性能较差。而高速列车车外噪声声源有其本身的源强分布特性。为预测实际列车运行下V型声屏障降噪效果，通过线路测试识别出高速列车声源空间分布特征，确定预测模型声源，对声屏障总降噪效果进行预测分析。结果表明，V型声屏障针对实测高速列车车外噪声降噪效果显著，相对直立声屏障而言，约降低1 dBA左右；针对轮轨区域声源，V型声屏障的降噪效果降低4 dBA左右，尤其是在500 Hz、1 250 Hz和2 000 Hz频率处降噪效果最好。

Experimental Study on the Sound Insulation Performance and Noise Reduction Effect Prediction of V-type Noise Barriers

To evaluating the noise reduction effect of the V-shaped noise barriers,their sound insulation performance is studied by combining experiment method with numerical prediction.First of all,the insulation of V- type noise barrier is measured in the lab.The result shows that the weighted sound insulation of the V-type barrier is 23.8 dB smaller than that of the vertical sound barrier,which means that its performance is poor.But high-speed trains have their own source intensity distribution characteristics.In order to predict the actual in- situ noise reduction effect of the V- shaped noise barrier,the spatial distribution characteristic of the sound sources of the traveling high speed train is identified by measurement.On this basis the model for prediction is established.The sound insulation effect of the barrier is predicted and analyzed.The results show that the V-type sound barrier can effectively reduce the exterior noise of the high-speed train,it can approximately reduce the noise by 1 dB（A） in comparison with the vertical barrier.For the sound sources in the wheel-rail area,the Vshaped noise barrier can reduce the noise by 4 dB.And the noise reduction effect is very good at 500 Hz,1 250 Hz and 2 000 Hz frequencies.