沙坪坝车站站房的振动传递研究

Study on Vibration Transmission of Shapingba Station

以重庆沙坪坝车站站房为研究对象,通过现场锤击试验,探讨站房的振动传递规律。对实测的振动信号进行时程与1/3倍频成分析,然后,将锤击作用下的站房振动与结构本底振动进行对比,得到站房结构的振动敏感频段,最后,基于有限元软件ANSYS建立站房结构有限元模型,计算站房的自振特性,并与试验数据进行对比。结果表明:人为锤击激励有限,在分析锤击引起的站房振动时不可忽略本底振动的影响;站房的本底振动优势频段为1 Hz^3.15Hz,峰值频段均为2 Hz;人为锤击激励在1 Hz^100 Hz均可激起较大的振动,覆盖本文探讨的所有频段;对轨道施加人为锤击激励时,站房与站台的振动敏感频段大致为31.5 Hz^80 Hz;高频振动沿传递路径衰减明显,锤击点不宜距测量点过远;计算得到站房前10阶自振频率在1 Hz^3 Hz,与实测的本底振动频率基本一致。

The vibration transmission rules of Chongqing Shapingba station were investigated by a hammer excitation field test. The measured results were analyzed both in time domain and 1/3 octave band frequency domain. Then, the measured vibration of the station induced by hammering was compared with the measured background vibration to get the sensitive vibration spectrum of the station. Finally, the finite element model of the station was established by means of ANSYS software. The natural vibration characteristics of the station were calculated and compared with those of the measurement data. Results show that due to the limited hammer excitation, background vibration should not be ignored when analyzing the vibration induced by the hammer excitation. The dominant frequency range of the background vibration is 1-3.15 Hz with the peak value at 2 Hz. In the range of 1-100 Hz, the hammer excitation can stimulate relatively large vibration, which can cover overall frequency ranges analyzed in this paper. When the hammer excitation acts on the rail, the vibration sensitive frequency range of the station and platform is 31.5-80 Hz. High-frequency vibration is more likely to be attenuated along the transmission path, thus the hammer excitation point should not be too far away from the measurement points. The calculated natural vibration frequency range of the station under 10 th natural vibration mode is located in 1-3 Hz range, which is essentially consistent with the frequency range of the measured background vibration.