Abstract
In order to find out the influence of subgrade frost heave on the deformation of track structure and track irregularity of high-speed railways, a nonlinear damage finite element model for China Railway Track System III (CRTSIII) slab track subgrade was established based on the constitutive theory of concrete plastic damage. The analysis of track structure deformation under different subgrade frost heave conditions was focused on, and amplitude the limit of subgrade frost heave was put forward according to the characteristics of interlayer seams. This work is expected to provide guidance for design and construction. Subgrade frost heave was found to cause cosine-type irregularities of rails and the interlayer seams in the track structure, and the displacement in lower foundation mapping to rail surfaces increased. When frost heave occured in the middle part of the track slab, it caused the greatest amount of track irregularity, resulting in a longer and higher seam. Along with the increase in frost heave amplitude, the length of the seam increased linearly whilst its height increased nonlinearly. When the frost heave amplitude reached 35 mm, cracks appeared along the transverse direction of the upper concrete surface on the base plate due to plastic damage; consequently, the base plate started to bend, which reduced interlayer seams. Based on the critical value of track structures’ interlayer seams under different frost heave conditions, four control limits of subgrade frost heave at different levels of frost heave amplitude/wavelength were obtained.
Highlights
Frozen soil regions are widely distributed throughout the world and are found in places such as Russia, Canada, China, Alaska, and Japan [1,2,3]
China Railway Track System III (CRTSIII) slab track will be used as the main track structure in these projects, which will pass through alpine regions where the average temperature in the coldest month in China is less than −10 ◦C, or the average daily temperature is not higher than 5 ◦C for more than 145 days
Combined with the relevant standards of irregularity management for the slab track of high-speed railways in maintenance rules and the results shown in Section 3, it can be asserted that the amplitude transfer ratio of subgrade frost heave is greater than 1.0
Summary
Frozen soil regions are widely distributed throughout the world and are found in places such as Russia, Canada, China, Alaska, and Japan [1,2,3]. It is necessary to pave and maintain the slab track in severely cold regions in order to study the deformation and seams in the track structure of high-speed railways under subgrade frost heave and put forward control limits for subgrade frost heave displacements in frozen soil regions. Based on the theory of vehicle–track coupling dynamics and using the finite element method, Gao et al [27] established an explicit dynamic analysis model for vehicle–slab track subgrade in the frost heaving area and researched the influence of frost heave amplitude and wavelength on the dynamic response of the vehicle track. In this study, combined with the concrete plastic damage constitutive theory, a nonlinear damage analysis model of CRTSIII slab track subgrade frost heave was established using the finite element method. It is expected that this study may provide theoretical guidance for the maintenance of CRTSIII slab tracks in cold areas
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