Fracture behavior investigation of ballastless track of high-speed railway based on DIC technique

To investigate the issues of transverse through cracks and interlayer damage of the CRTS III slab ballastless track under train loading, the digital image correlation (DIC) technique was employed to reveal the damage mechanisms of the reduced-scale concrete of track slab structural concrete (TSSC) and track slab-filled laminated structural concrete (TSLSC). The results indicate that under train loading, the transverse through cracks of TSLSC exhibit a multi-stage, layer-by-layer cracking characteristic, and there is a risk of cracking in ballastless track when the bottom longitudinal strain exceeds 0.0004. The sudden increase in interlayer longitudinal shear strain difference in the third stage under train loading demonstrates that shear stress is the primary cause of interlayer damage in ballastless track. Tensile damage models based on ultimate stress-strain relationship and yield-fracture strain were established, and a non-contact testing method for the constitutive relationship and energy absorption effect of ballastless track was proposed using DIC technology, aiming to provide reference for the analysis and prediction of ballastless track damage under train loading.