V型减载式声屏障降噪特性的试验研究

Experimental Study on Noise Reduction Characteristics of V-type Deloading Noise Barriers

V型减载式声屏障可减小高速列车气动载荷对声屏障的动力作用,但其透气结构降低了单元板件的隔声量,通过现场试验客观评价和分析其降噪效果具有重要工程意义。采用ISO3095标准,基于现场测试,对比分析了高速列车以车速为250 km/h～360 km/h通过状态下V型减载式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型减载式和传统直立型声屏障的插入损失均有较明显下降,但V型插入损失的下降相对缓慢。换言之,V型减载式声屏障与直立型声屏障的插入损失差异随列车通过速度的增加逐渐减小,并在350 km/h时两者相当,之后V减载式声屏障降噪效果将更佳。V型减载式声屏障在车速为250 km/h时插入损失为13.6 dB(A),比直立式的要小2.4 dB(A),而在车速为360 km/h时为10.2 dB(A),比直立式的要大0.3 dB(A)。声屏障降噪效果会随其高度的增加而增加,由2.95 m增大到3.95 m时,V型减载式声屏障降噪效果提高更明显,在车速为360 km/h时插入损失要大3.5 dB(A)。

The V-type deloading noise barriers can reduce the aerodynamic load of high-speed trains acting to the sound barriers, but its ventilation structure reduces the sound insulation effect of cell plates. Objective evaluation and analysis of noise reduction effect of the barriers through field tests are of important engineering significance. In this paper, based on the field test and according to the ISO3095 standard, the noise reduction effects of the V-type deloading barriers and traditional vertical type noise barriers are analyzed and compared mutually under the condition that high-speed train passes at the speed of 250 km/h-360 km/h. The results show that the insertion losses of V-type deloading barriers and vertical type noise barriers have obvious declines as the speed increases, but the insertion loss of the V-type deloading barriers declines relatively slow. In other words, the difference between the insertion losses of the V-type deloading barrier and the vertical type noise barrier decreases as the speed increases, and the difference between them is nearly the same at the speed of 350 km/h. The noise reduction effect of the V-type deloading noise barrier will be better than that of the traditional vertical barrier at the speed above 350 km/h. The insertion loss of the V-type deloading noise barrier is 13.6 dB（A） at the speed of 250 km/h, which is 2.4 dB（A） lower than that of vertical type noise barrier. At the speed of 360 km/h, it＇ s 10.2 dB（A）, which is 0.3 dB（A） larger than that of the vertical type noise barrier. The noise reduction effect of the noise barriers will be better as the barrier height increases. When the height is increased from 2.95 m to 3.95 m, the noise reduction effect of the V-type deloading noise barrier is improved more obviously and its insertion loss is increased by 3.5 dB（A）.