Effects of differential subgrade settlement on damage distribution and mechanical properties of CRTS II slab track

Abstract

Differential subgrade settlement adversely affects the slab track. In this study, a three-dimensional model of a slab track based on damage mechanics theory was established for analysing the effects of differential subgrade settlement on the damage distribution and mechanical properties of the slab track. The prestressed steel bars and ordinary steel bars in the precast slab of the slab track were refined. The rail supporting forces were employed as the train loads. The damage distribution, deformation, and longitudinal stress of the track under differential subgrade settlement cases were calculated using the model. The results indicated that with the increasing of settlement amplitude, the concrete base is damaged first. If the settlement amplitude continues to increase, the precast slab is damaged. The critical subgrade settlement amplitude of the initial damage of the track structure increases with the increasing of settlement wavelength. Under differential subgrade settlement, the steel bars in the precast slab were subjected to additional loads. However, the precast slab may also crack. Damage to the precast slab and concrete base destroys the integrity of the longitudinal connection system of the CRTS II slab track. Subgrade with differential settlement should be repaired in time to avoid serious damage to the track structure.