Analysis of the Sensitive Factors of Periodic Deformation of Unit Ballastless Track
Research purposes:In application,periodic track irregularity with the wavelength close to the slab length has been detected on unit ballastless track,which seriously affects running comfort.To analysis the sensitive factors of periodic deformation,taking the CRTS Ⅲ slab track as an example,a multi-physical field coupling analysis model of the ballastless track considering the nonlinear contact relationship between layers is established.The influence of temperature gradient and self-compacting concrete shrinkage in the track slab on the warping deformation and periodic irregularity of the track surface is analyzed,and the transfer relationship between two types of loads and periodic deformation is obtained.Research conclusions:(1)The greater the temperature gradient and the equivalent temperature decrease of concrete shrinkage,the greater the vertical deformation difference and the greater the transfer ratio of the rail.Under the temperature gradient of+90 ℃/m and-45 ℃/m,the vertical deformation difference of the rail is 0.72 mm and 0.32 mm,and the transfer ratio is 0.0158 mm/(℃·m-1)and 0.0183 mm/(℃·m-1).(2)Under the equivalent temperature decrease of-10℃,the vertical deformation difference of rail is 0.39 mm,and the transfer ratio is 0.073 9 mm/℃.(3)When combined with concrete shrinkage,the positive temperature gradient deformation effect is superimposed,and the negative temperature gradient deformation effect is canceled out.The deformation effect caused by-45 ℃/m temperature gradient is equivalent to that caused by concrete shrinkage of-10 ℃,which can be basically canceled out.(4)By controlling the timing of track precise adjustment and presetting a reasonable initial irregularity,the periodic irregularity of unit slab track during operation can be reduced.(5)The research results can provide theoretical guidance for controlling the periodic deformation of ballastless track,which is widely existing at present.
high speed railwayunit ballastless tracktemperature gradientconcrete shrinkageperiodic deformation
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