地铁隔振措施对钢轨声功率特性影响测试分析

Measurements and analysis of effects on rail sound power characteristics from metro vibration-reduction measures

当列车通过浮置板轨道和减振型扣件轨道等减振区段时,车内噪声较大,影响乘客的舒适性。滚动噪声是车内噪声的重要组成部分,而钢轨声功率反映了钢轨滚动噪声能量的大小。为了研究地铁隔振措施对钢轨声功率特性的影响,对不同隔振措施下钢轨垂向振动沿纵向的轨道衰减率和钢轨加速度导纳进行了测试,计算分析了单位简谐点激励下的钢轨垂向振动相对声功率级。结果表明所测隔振措施通过降低轨道垂向刚度,改变了钢轨垂向振动的加速度导纳幅值和轨道衰减率。钢弹簧浮置板道床和减振垫浮置板道床提高了三分之一倍频程中心频率200 Hz以下的轨道衰减率,而GJ-III型减振扣件长枕整体道床的衰减率在中心频率2 500 Hz以下小于非减振型扣件长枕整体道床。钢轨在受到单位简谐点激励作用时,浮置板道床的钢轨声功率在200 Hz以下明显增大,而GJ-III型减振扣件长枕整体道床的钢轨声功率在500 Hz以下明显增大。

When a train is crossing over the floating slab track or the track with vibration isolation fasteners,the vehicle interior noise is so high that it decreases the comfort of passengers.The rolling noise is the main part of the vehicle interior noise,and rail sound power reflects energy size of the rail rolling noise.In order to study the effects of vibration reduction measures on the rail sound power characteristics,the vertical track decay rates and rail acceleration mobility were tested,and relative rail sound power levels under the unit harmonic point excitation were calculated.The results show that vibration-isolation measures change the decay rate and rail acceleration mobility amplitude by decreasing the vertical track stiffness.The track decay rates of the steel-spring floating slab bed and the isolation-pad floating slab bed have been increased under 200 Hz,and the monolithic bed track with sleepers embedded and GJ-III vibration-isolation fasteners has the lower decay rate than that with DZIII-1 fasteners under 2 500 Hz.The rail sound power of the floating slab track increases greatly under 200 Hz while that of the monolithic bed track with GJ-III vibration-isolation fasteners increases greatly under 500 H,when the rail is loaded by the unit harmonic point excitation.