变高度槽型梁桥对轮轨噪声插入损失的影响

Influence of Trough Girders with Variable Heights on the Insertion Loss of Wheel-rail Noise

槽型梁在既有线改造中应用广泛,腹板可看作声屏障,对轮轨噪声能起到一定阻挡作用,在噪声传播路径中起到降噪的效果。针对不同边梁高度槽型梁的降噪效果进行研究,建立槽型梁二维边界元模型,以实测轮轨噪声为声源,计算其不同高度的边梁在考虑地面声反射和车厢壁反射时的声场和噪声插入损失,并与相同工况下U梁插入损失进行对比,分析边梁截面形式对轮轨噪声插入损失的影响规律。结果表明,边梁高度对其插入损失起主要作用,边梁高度越高,噪声向上传播时的夹角越小。车厢壁的反射效应会改变轮轨噪声在梁侧的分布,但对同一场点的插入损失影响不大。U梁与槽型梁的插入损失分布规律有所不同,槽型梁对桥梁下方噪声的遮挡效应更明显。

Trough girders are widely used in the overhaul of existing railways.The web of trough girder can be regarded as the sound barrier,which can reduce the wheel-rail noise in the propagation path.In this paper,the noise reduction effect of trough girders with various heights of side beam is studied through a two-dimensional boundary element model.Considering the reflection of ground and carriage,with the measured wheel-rail noise as the sound source,the acoustic field and insertion loss of the trough girder with various heights are calculated and compared with those of Ushaped beam in the same working condition.And the influence of the cross-section of the trough girder on the insertion loss of wheel-rail noise is investigated.The results show that the height of the side beam of the girder has a significant influence on the insertion loss.The higher the side beam is,the smaller the vertical angle of the upward propagation of the wheel-rail noise is.The reflection of the carriage to wheel-rail noise can change the distribution of sound pressure,but it has small influence on the insertion loss at the same point.The distribution of insertion loss of U-shaped beam and trough girder is different,and the shielding effect of trough girder is stronger than that of U-beam for the noise propagation from the deck to the underneath of the bridge.