Study on the Influence of Subgrade Settlement on Mechanical Properties of Ballastless Track and Train Operation Comfort
Subgrade settlement have adverse effects on durability of track structure,smoothness of track,train operation comfort and safety.In order to study the influence of subgrade settlement on track and train,the static and dynamic analysis model under the action of subgrade settlement were established based on the finite element and train-track coupling dynamic theory,and the influence of subgrade settlement on the mechanical properties of ballastless track and train operation comfort were studied.Based on the calculation results,the sensitive wavelength range of subgrade settlement is 5～25 m.The relationship formula of train vertical acceleration,wavelength and amplitude was obtained by the nonlinear least square fitting method,and then the calculation formula of subgrade settlement limit amplitude was deduced.It is suggested that treatment measures should be taken and settlement observation should be strengthened for the subgrade structure with settlement amplitude more than 15 mm,and the subgrade settlement amplitude more than 20 mm should be avoided.The results show that the deformation,stress and bending moment of track structure increase with the increase of subgrade settlement wavelength and amplitude.The vertical acceleration of train increases first and then decreases with the increase of wavelength,and increases approximately linearly with the increase of amplitude.
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