Analysis of Effects of Differential Subgrade Settlement on Damage and Deformation of CRTSⅡ Slab Track

Given the particular sensitivity of the slab track structure of high-speed railway to the subgrade settlement, the differential subgrade settlement will affect the stress deformation and service life of the track structure. According to the structural characteristics of the CRTSⅡ slab track on the subgrade, the concrete damaged plasticity model was used to characterize the mechanical property of the track structure and to analyze the damage and deformation laws of the track structure under differential subgrade settlement. The results show that the settlement amplitude of the subgrade corresponding to the initial damage of the concrete of the support layer is smaller than that of the track slab. The subgrade settlement amplitude corresponding to the initial damage of the support layer is about 14 mm, and that of the track slab is about 19 mm when the subgrade settlement wavelength is 20 m. An obvious separation exists between the support layer and the subgrade when the settlement amplitude is 15 mm and the settlement wavelength is less than 20 m. More attention should be paid to the short-wave differential settlement. The settlement of the track structure and upward camber of the track on both sides of settlement area increase with the increase in the subgrade settlement amplitude. The concrete damaged plasticity model can well describe the concrete softening and stiffness degradation of the track structure under the condition of differential subgrade settlement.