Mechanical Characteristics of Ballastless Track under Subgrade Frost Heaving in High-speed Railway
ZHAO Guo-tang1, ZHAO Lei2, ZHANG Lu-shun3
(1. China Railway Corporation, Beijing 100844, China; 2. Railway Engineering Research Institute, China Academy of Railway Sciences, Beijing 100081, China; 3. Beijing Jiaotong University, Beijing 100044, China)
Abstract：Abstract：Research purposes： High-speed railway subgrade frost heaving is very common in seasonal frozen area, local subgrade frost heaving will bring a great impact on the ballastless track force, and may even lead to structural layer cracking. In this respect, coupling models of different types of ballastless track-subgrade system under subgrade frost heaving in high-speed railway are established. Based on the input conditions of subgrade frost heaving deformation curves, the effects of wavelength and amplitude of frost heaving deformation on the mechanical characteristics of different types of ballastless tracks are calculated and analyzed, the effect of the introduction of the sealing layer of asphalt concrete under the bed plate of CRTSⅢ ballastless track and optimization effect of boss restrict on bed plate are both analyzed. Research conclusions： (1) The stress of the ballastless track structure increases as the increase of the amplitude of frost heaving deformation and the decrease of wavelength of frost heaving deformation. (2) The maximum longitudinal tensile stress of track slab and supporting layer is lager in bi-block ballastless track under subgrade frost heaving, the structure is prone to cracking, thus inappropriate to be applied to seasonal frozen areas. (3) The groove on the bed plate of CRTSⅢ ballastless track is the bearing weakness under frost heaving deformation, after optimized to boss restrict, the structure force can be significantly reduced under the foundation deformation. (4) When the asphalt concrete layer is laid under the bed plate of CRTS III ballastless track, the stress of the track slab and the bed plate simultaneously shows a decreasing trend. The lower the elastic modulus of asphalt concrete is, the greater the decrease of stress is. (5) The conclusion of this paper can provide a reference for the development of subgrade frost heaving control standard and the selection of ballastless track for high-speed railway in seasonal frozen area.
2017, Vol. 34 
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