高速铁路大跨度混合梁斜拉桥-无砟轨道隔离层减振效果试验研究

Experiment Research of the Vibration Attenuation Effect of Ballastless Track Isolation Layer of High Speed Railway Long Span Hybrid Beam Cable Stayed Bridge

为提高无砟轨道在大跨度桥梁应用的适用性,在无砟轨道层间引入橡胶隔离层以代替传统土工布隔离层。橡胶隔离层的引入改变了桥上无砟轨道的振动特征,并兼具一定的减隔振作用。结合昌赣高铁赣州赣江特大桥混合梁斜拉桥铺设无砟轨道的需要,对桥上CRTSⅠ型双块式无砟轨道不同隔离层的减振效果开展试验研究,对非减振型与减振型轨道板进行多工况激振,根据动力响应时-频结果,得到了不同隔离层下的无砟轨道纵向、竖向传递规律。研究表明:(1)钢轨的激振频率集中在2~3 kHz,振动在传递中会向高频段漂移,非减振板的漂移现象更明显,减振板在该频段衰减明显,最大相差28 dB;(2)振动沿钢轨传递过程中,非减振板的衰减规律与距离呈正相关,减振板在很近距离内衰减至最低量级;(3)竖向传递规律中,两种轨道板的激振频段均变为宽幅0~3 kHz激振,幅值接近,在2 kHz处出现峰值,传递到钢箱后振动均被放大;(4)竖向传递规律中,两种板型在桥面板处差异明显,非减振板集中在0~500 Hz、2 kHz处,减振板集中在0~500 Hz处;减振板在0~3 kHz频段处的级差平均比非减振板高20 dB,衰减效果明显。

In order to promote the use of ballastless track in long span bridges,traditional geotextile layer is replaced by rubber layer,which changes the vibration pattern of the ballastless track on the bridge and offers certain vibration attenuation effect.In view of the need of the Ganjinag River grand span hybrid girder cable-stayed bridge in Nanchang-Ganzhou High Speed Railway construction project,this paper conducts a multi-condition excitation vibration experiment research on the vibration attenuation effect in CRTSⅠballastless track isolation layer of cable stayed bridge.According to the time-frequency result,the longitudinal,vertical vibration patterns of different layers are acquired.The research results show that(1)The excitation frequency band of rail is 2~3 kHz,the frequency transfers to higher band during longitudinal transmitting,and the rubber layer is transferred much more.The rubber layer vibration attenuates by maximum 28 dB at this frequency band;(2)During longitudinal transmitting,the transmit is decreased positively in correlation with distance,while the rubber layer decreases to a minimum value in a short distance;(3)During vertical transmitting,both track slabs are widely excited from 0 to 3 kHz with approximate amplitude and peak value at 2 kHz;after the vibration is transmitted to steel box girder,the vibration is amplified;(4)During vertical transmitting,the two types of board have remarkable difference at the deck slab,the geotextile layer board has excite band of 0~500 Hz and 2 kHz,while the rubber layer board has excite band only at 0~500 Hz.And the rubber layer board has higher attenuation effect by average 20 dB at 0~3 kHz band than the geotextile layer board.