Interfacial fatigue reliability of CRTS III slab ballastless track under material uncertainty: a combined experimental and numerical study

Abstract This paper investigates the fatigue reliability of the interfacial bonding in the concrete–concrete composites of CRTS III slab ballastless track structure under material uncertainty, using combined parametric experiments and numerical simulations. First, based on the fatigue constitutive model of interfacial bonding, parametric experiments are conducted to identify basic variables. Then, by integrating existing data, uncertainty quantification is performed for both the bonding and concrete to obtain the probability distributions of random variables. Moreover, the probability density evolution method is adopted to assess the interfacial fatigue reliability, based on finite element simulations of CRTS III slab ballastless track under fatigue temperature loading. The experimental results confirm the presence of significant material uncertainties, which underscores the necessity of shifting from a deterministic to a stochastic perspective for addressing the interfacial fatigue. The simulation results reveal that the interfacial fatigue reliability drops rapidly with service time. When the formulated level-II damage limit is employed as the maintenance criterion, the reliability decreases to 0.80, 0.48, and 0.17 after 10, 30, and 60 years, respectively. These findings indicate relatively weak durability of the interfacial bonding in concrete–concrete composites of CRTS III slab ballastless track and highlight the need of significant efforts from maintenance departments.