钢弹簧浮置板轨道低频特征试验研究

利用北京交通大学轨道减振与振动控制试验室开展钢弹簧浮置板轨道低频特征测试,研究钢弹簧浮置板轨道弹簧刚度和支承间距等参数变化对低频振动的影响,并比较钢弹簧浮置板轨道和普通轨道的低频减振效果。试验结果表明:①弹簧总刚度越大(支承间距不变且弹簧刚度越大,或弹簧刚度不变且支承间距越小),浮置板轨道基频越大,轨道板到基底竖向加速度级传递损失越小,轨道板到隧道内的竖向传递函数值越大;②钢弹簧浮置板轨道基频越小,在其工作频段,减振效果越好;但在基频附近,振动放大现象越明显。相对于普通轨道,钢弹簧浮置板轨道明显降低了10Hz以上频段的振动响应,最大减振量为25dB;同时基频处的振动放大量为25dB;③对于轨道板到隧道内的竖向传递函数,普通轨道的值比钢弹簧浮置板轨道的值大,前者在0.012～0.028之间,后者在0～0.01范围内。

Experimental study of the low-frequency vibration characteristics of steel spring floating slab track

Low-frequency vibration tests on Steel Spring Floating Slab Track(SSFST) and ordinary track in the Laboratory of Track Vibration Abatement and Control at Beijing Jiaotong University are carried out to study the influence of various key parameters including the stiffness and spacing of steel springs,the difference of vibration mitigation efficiency between the SSFST and the ordinary track.The results indicate that: ①The basic frequency of the SSFST and the vertical transfer function from the slab to the tunnel increase with the increase of the total spring stiffness of the SSFST,while the reduction of the vertical vibration transfer function between the slab and the invert decrease.②The smaller the basic frequency of the SSFST,the better the vibration mitigation efficiency beyond the isolation frequency,though the more obvious the vibration amplification around the basic frequency.Comparing with the ordinary track,the SSFST could isolate vibrations at frequencies greater than 10Hz,and the maximum insertion loss is 25dB,however,the amplified vibration at the basic frequency can be as high as 25dB.③The vertical transfer function from track slab to tunnel for the SSFST is greater than that for the ordinary track,with the former being about 0.012~0.028,and the latter 0~0.01.