Influence and sensitivity analysis of mortar void in CRTS II ballastless slab track on the vehicle-track dynamics

Mortar void is the most prevalent disease in CRTS II ballastless slab track aggravating the service performance of vehicle and track structures. For determining a reliable mortar void limit, the influence of mortar void on the vehicle-track dynamics are analyzed through a refined rigid vehicle-flexible track coupled model, considering the randomness induced by track irregularity. Sensitivity analysis of mortar void are conducted taking into account train operation speeds and track irregularities measured from different railways. The findings suggest that when the train speeds are 250 km/h, 300 km/h and 350 km/h, respectively, mortar void length should be less than 0.98 m, 0.93 m and 0.81 m. Additionally, the impact of mortar void on the vehicle-track system dynamics becomes more pronounced as the amplitude of track irregularity decrease. This study provides a valuable insight for developing an effective maintenance plan for mortar void in CRTS II ballastless slab track.