近轨低矮声屏障降噪效果影响因素分析

针对城轨交通近轨低矮声屏障,为了量化分析其降噪特性和效果,以对称点声源模拟轮轨声源,考虑车体和轨道结构的空间几何构型及声学边界特性,采用声学边界元法,建立城轨列车车外噪声预测分析模型,对有无声屏障以及不同吸声处理方式下的空间声场响应进行对比分析。研究结果表明:对标准评价点(距轨道中心线7.5 m远,距轨面1.2 m高),0.25 m高直立型无吸声声屏障的插入损失为-1.7 dB(A);若其高度每增加0.25 m,插入损失将增加0.4dB(A)~2.9 d B(A);若在1.0 m高直立型无吸声声屏障的屏体内侧以及轨道增设吸声边界条件,插入损失增加6.1 dB(A);若对1.0 m高直立型无吸声声屏障增设Y头型,插入损失将增加2.7 dB(A)。相关研究可为城轨交通减振降噪提供科学指导。

Analysis of the Factors Affecting Noise Reduction of Near-rail Low-height Noise Barriers

In order to quantitatively analyze the noise reduction characteristics and effects of near-rail low height noise barrier, the symmetrical point sound source simulates the wheel-rail sound source. Considering the spatial geometry and acoustic boundary characteristics of the vehicle body and the track structure, the acoustic boundary element method is used to establish the vehicle exterior noise prediction model, and the spatial sound field response under the sound barrier and sound absorption treatment is compared and analyzed. The results show that the insertion loss of 0.25 m high vertical no absorption sound barrier is -1.7 dBA at the standard evaluation point (7.5 m away from the track centerline, 1.2 m high from the track surface). If the height of sound barrier increases by 0.25 m, the insertion loss will increase by 0.4~2.9 dBA. If the sound absorber is added inside the barrier of the 1.0 m high vertical no absorption sound barrier, as well as the track structure, the insertion loss increases by 6.1 dBA. If the Y-head is added to the 1.0 m high vertical no absorption sound barrier, the insertion loss will increase by 2.7 dBA. The related research results can provide scientific guidance for urban rail transit vibration and noise reduction.