Cyclic behaviour of coarse-grained materials exposed to freeze-thaw cycles: Experimental evidence and evolution model

Abstract

With the rapid development of high-speed railways (HSRs) in seasonally frozen regions in China in recent years, there is an increasing need for better understanding of how the construction materials behave. In particular, the dynamic behaviours of coarse-grained materials (CGMs) used for China's HSRs subjected to combined actions of cyclic loading and freeze-thaw (F-T) cycles has attracted much attention. In this study, a series of cyclic triaxial tests were performed to investigate the characteristics of CGMs considering the effects of number of F-T cycles (NFT), confining pressures (σ3), dynamic stress amplitude (σ¯d), and fines content (FC). Representative test results of accumulative axial strain (εacc), resilient modulus (Mr), dynamic shear modulus (Gd) and damping ratio (D) are then presented and discussed. Empirical models are proposed and validated for predicting the evolution of εacc and Mr for CGMs under the cyclic loading. In addition, the evolution models of Gd and D were established, which can be used for computing the response of CGMs under various influencing factors. Overall, this study provides further insights into the cyclic behaviours of CGMs in seasonally frozen regions.