Lifetime damage evolution of concrete joints in CRTS II slab track using mesoscale modelling under combined thermal action and vehicle load

Abstract

The condition of the concrete joints in the slab track of the China Railway Track System (CRTS) II is crucial to the safe operation of high-speed railways. In order to predict the lifetime damage evolution of the concrete joint under the combined thermal action and vehicle load, a new coupled thermal-mechanical numerical model at the mesoscale is developed. First, the meteorology and heat transfer principles are adopted to simulate the temperature distribution of the slab track. The heterogeneous characteristics of the joint concrete are modelled by the concrete plastic constitutive model and random aggregate algorithm at the mesoscale. Then, the plastic strain state of the concrete joint can be obtained by the coupled thermal-mechanical analysis. The proposed numerical model can provide reliable predictions for the temperature distribution, and the concrete modelling at the mesoscale can accurately reflect the corresponding mechanical properties, which is confirmed by the relevant field measurements. Finally, the lifetime of the concrete joint is estimated by the accumulative residual plastic strain damage model associated with the plastic strain state under the combined thermal action and vehicle load. From the obtained results for the numerical example, the most vulnerable zone of the concrete joint is located at the top part of the T-shape concrete joint, and the climate change can significantly reduce the lifetime of the concrete joints in the slab track.