Vertical Stability of Longitudinal Continuous Ballastless Track Under Temperature Variation

To study the vertical instability form and process of a longitudinal continuous ballastless track, the arch curve of the slab that is influenced by temperature can be deduced based on the deflection differential equation of the Euler beam. The equation of the arch camber and wavelength of the slab was obtained from the arch curve. The equilibrium path of the slab with the initial arch was analysed based on stationary potential energy. Compared with the method of assuming a deformation, the method of solving differential equations is more accurate, and the error is reduced by nearly 30%. The course can be divided into three stages: steady, expansion, and destabilization. The limit of the steady and expansion stages decreases along with the increase of the initial arch camber. The effect of the release of slab temperature on the equilibrium path shows that the path appears as a stiffening stage, and the larger the friction coefficient, the earlier the stage occurs, whereas it has little effect when the deformation is small. The larger the initial camber, the greater the allowed wavelength is. When the initial arch is smaller than 50 mm, the vertical instability of the slab does not occur.