Influence of performance deterioration of self-compacting concrete on the load effect of CRTS Ⅲ slab track
The filling layer is the key component of CRTS Ⅲ slab track structure.Due to the typical"sandwich"structure of the slab track structure,the filling layer is susceptible to environmental influences,leading to degradation of the track structure,which is unfavorable to the track structure.To explore the influence of filling layer self-compacting concrete performance deterioration on the load effects of the slab track structure,the finite element model of track structure with overall damage conditions and gradient damage conditions closer to the actual use of the filling layer were established by ABAQUS software combined with the existing experimental results of damage of filling layer concrete.The variations of stress and displacement of slab track,filling layer and base plate in the track structure under different train load and temperature load were calculated,and the influence of filling layer attack by fatigue damage on the performance of the track structure was analyzed.Results show that the overall damage of filling layer concrete leads to a significant decrease in its stiffness.Under train and temperature loads,the composite plate consisting of the track slab and filling layer experiences displacement in multiple directions,resulting in increasing local wear and unevenness in the track structure.When the filling layer is subjected to load,the stress in all directions decreases significantly.The overall stress of the slab track increases and is prone to stress concentration.Compared with its upper structure,the stress of the base plate is less affected by the change of the filling layer performance.When the gradient damage occurs around the filling layer,the changes of stress and displacement develop continuously change from the damaged area to the undamaged area under different loads,and there is no obvious stress concentration and stress mutation.Under different loads,the stressed region of the track structure affected by damage exhibits noticeable stress decrease,while the undamaged central region of the track structure experiences stress increase,accelerating the dynamic fatigue effects in that area and indirectly contributing to fatigue damage in the track structure.
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