A semi-empirical elasto-plastic constitutive model for coarse-grained materials that incorporates the effects of freeze-thaw cycles

© 2020 Elsevier Ltd A volume-shear coupling mechanism is imperative for developing high-speed railways in very cold regions. A series of consolidated drained static triaxial experiments were carried out to investigate the effect of freeze-thaw (F-T) cycles on the stress-strain features of coarse-grained materials (CGM) typically used at the bottom layer of subgrade for high-speed rail tracks in China. Mathematical expressions describing the effect of F-T cycles for residual stress state stress ratio, elastic shear modulus, and specific volume have been proposed. Laboratory observations enabled an empirical dilatancy equation to be incorporated in a constitutive model to capture the salient aspects of the monotonic deformation behaviour of CGM including the F-T effects. After comparing with experimental observations and validating through past independent studies, the proposed constitutive model could accurately predict the monotonic shear behaviour of the CGM exposed to F-T cycles