Influence of Interface Crack on Impact Dynamic Properties of CRTS III Slab Track-Subgrade System

To investigate the influence of the interface crack on the dynamic characteristics of high-speed railway infrastructure, a wheel-drop test was performed using the full-scale experimental platform of CRTS III ballastless track-subgrade system. The distribution of the one-sided interface crack between the slab and self-compacting concrete layer was measured and summarised. The 3D dynamic finite element model of the CRTS III track-subgrade system with a one-sided interface crack was established using the ANSYS/LS-DYNA software. The influence of the interface crack subjected to the wheel-drop load was investigated on the basis of comparisons between the experimental data and numerical results. The results indicate that the average width and height of the interface are 28.18 cm and 2.15 mm, respectively. The crack width has a stronger effect than the crack height on the infrastructure dynamic reaction. When the crack width increases within a range of 0 to 800 mm, all the displacements of the infrastructure and the accelerations of the rail and slab increase proportionally with the increase of the crack width. When the crack width approaches the distance between the rail and slab edges in the lateral direction, the accelerations of the filling layer, concrete basement, and subgrade reach their respective maxima. The maximum icrements of the displacement and the acceleration for the track and the subgrade are both occurred in the slab, which are respectively 56.8% and 143.3%. All the displacements and accelerations of the track and subgrade slightly increase with the increase of the crack height from 0 to 3 mm, and the maximum increments are 8% and 12%, respectly. The influence of the crack is more remarkable on the dynamic properties with the decrease of the distance between the infrastructure level and the crack locsation.