高速铁路钢轨焊接区不平顺的动力效应及其安全限值研究

应用车辆–轨道耦合动力学理论及其仿真分析软件TTISIM,研究了钢轨焊接区低塌不平顺对轮轨动力响应的影响特征,分析了高速行车条件下典型焊接区低塌不平顺波长和幅值对轮轨动力响应的影响规律,在此基础上,提出了高速铁路钢轨焊接区不平顺幅值的安全限值.分析结果表明:钢轨焊接区不平顺会导致明显的轮轨冲击效应,且该冲击作用由短波不平顺所控制;高速行车条件下,轮轨动力响应随着焊接区不平顺波长的增大而减小,随行车速度和不平顺幅值的增大而增大,其中,轮重减载率指标受不平顺波长和幅值的影响更为显著,为钢轨焊接区不平顺作用下行车安全性的首要控制指标;高速行车条件下,钢轨焊接区不平顺幅值的安全限值随行车速度的增大而减小,随不平顺波长的增大而增大,叠合形不平顺幅值的安全限值受短波不平顺(波长小于0.2 m)波长和幅值的影响较大;在200~250 km/h行车速度等级,1 m直尺测量矢度条件下,余弦形低塌不平顺幅值的安全限值为0.82 mm,叠合形低塌不平顺在1 m长波幅值为其作业验收限值0.3 mm时,其短波不平顺幅值的最大安全限值为0.2 mm,叠合形不平顺幅值总的安全限值最大为0.5 mm;在250~350 km/h行车速度等级,1 m直尺测量矢度条件下,余弦形低塌不平顺幅值的安全限值为0.62 mm,叠合形低塌不平顺在1 m长波幅值为其作业验收限值0.2 mm时,其短波不平顺幅值的最大安全限值为0.14 mm,钢轨焊接区叠合形低塌不平顺幅值总的安全限值最大为0.34 mm.研究结果可为高速铁路钢轨顶面焊接区不平顺的养护维修管理提供理论参考.

Dynamic effect and safety limits of rail weld irregularity on high-speed railways

By means of the vehicle-track coupled dynamics theory and the corresponding simulation software TTISIM, the effect of track concave irregularity located in rail weld zone on the dynamic responses of vehicle and track coupled system was investigated. The influence of the wavelength and amplitude of typical rail concave irregularity on wheel/rail dynamic responses was analyzed under high-speed operation. On this basis, the safety limits of rail concave irregularity were discussed. The results show that the rail concave irregularity will lead to obvious wheel/rail impact effect which is controlled by the shorter wavelength irregularity. Under high-speed operation, the wheel/rail dynamic responses decrease with the increase of irregularity wavelength, and grow gradually with the increase of running speed and irregularity amplitude. The wheelset decreasing ratio, which is the most affected dynamic index, becomes the controling index for running safety under the excitation of rail weld irregularity. The safety limits of rail weld irregularity decrease with the increase of running speed and rise with the increase of irregularity wavelength. For the overlapping shape weld irregularity, the safety limit is affected greatly by its short wavelength irregularity（wavelength is less than 0.2 m）. At 200-250 km/h speed class and under lm measurement scope, the safety limit of the cosine shape irregularity in rail weld zone is 0.82 mm, the maximum limit for the short wavelength irregularity of overlapping shape weld irregularity is 0.2 mm when the amplitude of the 1 m wave is 0.3 mm（the acceptance tolerance of 1 m wave）, the maximum safety limit of the overlapping shape weld irregularity is 0.5 mm. At 250-350 km/h speed class, and under lm measuremen scope, the safety limit of the cosine shape irregularity in rail weld zone is 0.62 mm, the maximum limit for the short wavelength irregularity of overlapping shape irregularity is 0.14 mm when the amplitude of the 1 m wave is 0.2 mm（ the acceptance tolerance of 1 m wave）,