Study On The Effect Of Subgrade Frost Heaving On The Deformation Properties Of Track Structure And Its Vehicle Dynamic Behavior In High-Speed Railway

As the high-speed railway construction in severe cold region develops quickly, subgrade frost heaving become a major engineering issue that needs to be solved in high-speed railway construction and operation management. On the one hand, it will destroy the overall irregularity of the track and threatens the running safety and riding comfort, On the other hand, it will damage track structure and affect the service life of track structure.Therefore, research on ballastless track deformation and its vehicle dynamic behavior under the condition of subgrade frost heaving is of important practical significance and engineering application value. Based on the investigation on field experiment data of subgrade frost heaving on high-speed railway in seasonal frozen soil regions and relevant literatures, the variation of track geometry irregularity and the influence caused by subgrade frost heaving on high-speed railway has been researched in this paper. And the effect of different degrees of deformation of subgrade frost heaving on track geometric deformation, interlamination contact state and the dynamic performance of high speed driving has also been anylized. The control limit value of subgrade srost heaving on high-speed railway is discussed preliminarily. The research works carried out are listed as follows:Firstly, Based on the investigation on field experiment data of subgrade frost heaving on high-speed railway in seasonal frozen soil regions and relevant literatures, deformation laws of subgrade frost heaving and laws of development and change of the track irregularity over time have been analyzed. Result shows that, the subgrade frost heaving features universality and randomness in seasonal frozen soil region and the deflection is relatively small. The development of track irregularity over time can be divided into four stages:the initial frost fluctuation, rapid development, stable of frost and rapid decline The track irregularity is characterized by significant nonlinearity and randomness.Secondly, the effect of different degrees of uneven deformation of subgrade frost heaving on track geometric deformation and interlamination contact State has been analyzed by using the transfer model of subgrade frost heaving deformation. The study found that the upper layers of slab track structure deform accordingly with the subgrade frost heaving under gravity, and the tack irregularity peak value and frost heaving deformation peak value were close. When the wavelength of subgrade frost heaving is short, the irregularity wavelength transmitted to the surface of the ballastless track increased. With the increase of the wavelength of the frost heaving, both deformation tends to be consistent and the contact state between layers is improved. The deformation and the contact state between layers is affected comprehensively by the wavelength and amplitude of the subgrade frost heaving.Finally, the dynamic response of system under subgrade frost heaving is investigated. On this basis, the control limit value of subgrade frost heaving on high-speed railway is discussed preliminarily. Research shows frost heaving will increase dynamic interaction between wheel and rail, influence running safety and riding comfort, and cause larger dynamic displacement of track structure. Through Further calculation and analysis show that dynamic interaction between wheel and rail is affected by the driving speed and the wavelength and amplitude of the subgrade frost heaving. Dynamic displacement of track structure, running safety and riding comfort should be taken into consideration when establishing management standards of subgrade frost heaving in seasonal frost area. Frost heave with short wavelength has significant effect on the dynamic interaction between wheel and rail and can easily cause void between the base and subgrade surface, which will result in the increase of dynamic deformation of the structure. Measures should be taken to eliminate them in time.