In complex service condition, China railway track system (CRTS) Ⅲ slab track structure is prone to high-cycle fatigue damage under repeated train loads. The material subroutine of the high-cycle fatigue damage constitutive relationship for self-compacting concrete was established, and the influences of train load, initial degradation of self-compacting concrete and slab ends cavity on the fatigue damage of the filling layer were researched with the full coupling method.The research shows that the full coupling method can reveal the coupling relationship between fatigue damage and structural stress, which makes up for the limitation of traditional decoupling method that the structural stress does not change with the accumulation of damage.And, only the train fatigue load and the initial deterioration of self-compacting concrete are considered, the damage accumulation of the filling layer approximately obeys the Miner criterion during the service period. In addition, slab ends cavity is the main factor influencing fatigue damage of self-compacting concrete layers.Besides, considering the influence of the above factors on the fatigue damage of the self-compacting concrete layer, after the void length of the slab ends reached to 0.9 m, the fatigue damage of the filling layer accumulated nonlinearly and the flexural stress decrease with the accumulation of fatigue damage.When the length of the slab ends cavity is 1.2 m, fatigue failure and stress redistribution occur in the filling layer, and the flexural stress transfers from the damaged area to the undamaged area. © 2023 Huazhong University of Science and Technology. All rights reserved.
