轨道交通桥梁低矮弧形声屏障降噪性能研究

A study on noise reduction performance of low-height curved noise barriers on rail transit bridges

以某城市轨道交通高架低矮弧形声屏障作为研究对象,分别选取有、无声屏障断面,开展列车通过时的噪声测试;基于有限元法、边界元法和统计能量分析法,建立轨道交通高架综合噪声预测模型并进行了试验验证。基于测试结果和预测结果,研究了城市轨道交通高架噪声的空间分布规律,分析了低矮弧形声屏障的降噪特性,探讨了低矮弧形声屏障对梁侧噪声分布的影响。研究结果表明:在无声屏障断面的情况下,轨面以下测点主要受低频桥梁结构噪声的影响,噪声随距离的衰减速度较慢,距离每增大一倍,噪声衰减约2.44 dB(A);轨面以上测点主要受高频轮轨噪声影响,噪声随距离的衰减速度较快,距离每增大一倍,噪声衰减约5.68 dB(A);低矮弧形声屏障对中高频噪声具有较好的降噪效果,但增大了低频噪声,这可能是由于声屏障的二次结构噪声辐射所导致的;低矮弧形声屏障在距离线路中心线7.5 m, 25 m处的插入损失分别约为5~8 dB(A)和2~6 dB(A);低矮弧形声屏障在梁侧插入损失约为4~6 dB(A),由于声屏障振动辐射二次结构噪声,桥梁跨中断面局部区域噪声增大。

The low-height curved noise barriers installed on an urban rail transit viaduct were taken as the research object.The sections with and without noise barriers were selected,respectively,to carry out the noise test when the train passes.A total noise prediction model of rail transit viaduct was established by using the finite element method,boundary element method,and statistical energy analysis,and was then verified by the test.Based on the test and prediction results,the noise spatial distribution of the elevated urban rail transit was studied,the noise reduction characteristics of the low-height curved noise barrier were analyzed,and the influence of low-height curved noise barrier on the noise distribution beside the bridge was discussed.Results show that the measuring points below the rail surface are mainly influenced by low frequency bridge-borne noise.The noise below the rail surface decrease slowly with distance,which decrease about 2.44 dB(A)when the distance doubled in the section without noise barrier.The measuring points above the rail surface are mainly influenced by high frequency wheel-rail noise.The noise above the rail surface decrease rapidly with distance,which decrease about 5.68 dB(A)when the distance doubled in the section without noise barrier.The low-height curved noise barrier has good noise reduction effect on the middle and high frequency noise,but increases low frequency noise,which may be caused by the secondary structure-borne noise radiation of the noise barrier.The insertion losses of low-height curved noise barrier are about 5-8 dB(A)and 2-6 dB(A)at 7.5 m and 25 m from the center of the rail line,respectively.The insertion loss of low-height curved noise barrier is about 4-6 dB(A)beside the bridge.Due to the secondary structure-borne noise radiated from the low-height curved noise barrier,the noise increases in local areas of the bridge mid-span section.