V型减载式声屏障降噪特性的试验研究

V型减载式声屏障可减小高速列车气动载荷对声屏障及其基础安装结构的动力作用，但其透气结构降低了单元板件的隔声量，通过现场试验，客观地评价和分析其降噪效果对其工程应用具有重要的意义。采用ISO3095标准，基于现场测试，对比分析了高速列车以250km/h~360km/h通过状态下，安装V型或传统直立型声屏障的降噪效果。结果表明：随着列车运行速度的增加，V型减载式声屏障和传统直立型声屏障的插入损失均有较明显的下降，但V型插入损失的下降相对缓慢，在250km/h时其插入损失为13.6dBA，而360km/h时为10.2dBA，降幅为3.4dBA。对3.95m高的V型减载式声屏障与直立声屏障，当速度小于350 km/h时，直立声屏障的降噪效果更好，插入损失要大0.1~2.4 dBA；当速度大于350 km/h时，V型减载式声屏障的降噪效果更好，插入损失要大0.3 dBA。当V型减载式声屏障与直立声屏障的高度由2.95m增大到3.95m时，V型减载式声屏障的降噪效果提高的更明显，在360km/h时插入损失要大3.5 dBA。

Experimental Study on Noise Reduction Characteristics ofV-type Deloading Noise Barriers

The V-type deloading noise barrier can reduce the aerodynamic load of high-speed train on the sound barrier’s dynamic effect, but its ventilated structure reduces the sound insulation of cell plate. Its noise reduction effect is evaluated and analyzed by the field test, which has important engineering application significance. With the ISO3095 standard, the noise reduction effect of the V-type deloading and traditional vertical type noise barrier are analyzed and compared under the condition that high-speed train passes at the speed of 250~360 km/h. The results show that the insertion losses of V-type deloading and vertical type noise barrier have an obvious decline as the speed increases, but the decline of V-type deloading noise barrier’s insertion loss is relatively slow. In other words, the difference between the insertion losses of the V-type deloading and vertical type noise barrier decreases as the speed increases, and the difference is about the same at the speed of 350km/h. The noise reduction effect of the V-type deloading noise barrier will be better at a higher speed. The insertion loss of V-type deloading noise barrier is 13.6 dBA at the speed of 350 km/h, which is 2.4 dBA lower than that of vertical type noise barrier. At the speed of 360 km/h, it’s 10.2 dBA, which is 0.3 dBA larger than that of vertical type noise barrier. The noise reduction effect of noise barrier will be better as the height increases. When the height is increased from 2.95 meters to 3.95 meters, the noise reduction effect of V-type deloading noise barrier improves more obviously and the insertion loss of which is larger 3.5 dBA .