Damage destruction evolution law of high-speed railway CRTS II slab ballastless track interface under train braking and temperature load

Abstract

The train braking and temperature load are simplified as shear loads and based on the cohesive stress constitutive model and test parameters, an interfacial nonlinear finite element model for the cohesion-displacement relationship of high-speed railway CRTS II slab ballastless track interface was established and verified by theoretical analysis. Damage destruction evolution law of the interface under shear loads, and the influence of shear steels on the interfacial longitudinal maximum cohesion and ultimate yield displacement are studied. Results indicates that the error between axial force difference of track slab and the interfacial constraint reaction is no more than 2%, which verified the correctness of the interfacial nonlinear finite element model; the longitudinal displacement of track slab increases with the increase of shear loads, and it decreases as the distance from the loading end increases; the interfacial longitudinal cohesion can fluctuate up and down at a certain value with the increase of longitudinal displacement, and then the interface gradually loses cohesion until it is completely destroyed and enters the sliding state. The three shear steels layout forms are all made the interfacial longitudinal maximum cohesion and ultimate yield displacement increase, the contributions of interfacial longitudinal maximum cohesion are 21.46%, 23.54% and 53.03%, respectively, and the contributions of ultimate yield displacement are 9.72%, 15.61% and 44.92%, respectively. Shear steel plays an important role in satisfying deformation demand of track structure.