Permanent deformation prediction model for freeze–thaw coarse–fine mixture of geomaterials with varying fine content: Influence of loading frequency

The impact of cyclic loading frequency (fcyc) on the permanent deformation (εp) of freeze–thaw coarse–fine mixture of geomaterials (FTCF) has been extensively investigated. In this work, long-term cyclic triaxial tests were conducted on FTCF specimens with varying fcyc and deviatoric stress (qcyc) with different numbers of freeze–thaw cycles (NFT), in order to investigate εp under freeze–thaw cycling. This study systematically analysed and discussed the effects of fcyc and qcyc on εp of FTCF samples with different fine particle contents (FC). A rate-dependent multistage load-prediction model for εp was proposed and evaluated. The results showed that the freeze–thaw cyclic had a less significant impact on εp when compared to the dynamic triaxial loading. The speed and piston effects of the FTCF under dynamic loads were mutually restricting, with their combined impact closely related to the loading frequency. A higher deformation resistance for a coarse-grained skeleton is attained with the effective filling of fine particle clusters in the pores of skeleton. A function was proposed to describe the relationship between the hyperbolic model parameters and fcyc, qcyc, as well as FC. This function could be used to estimate the hyperbolic model parameters under different dynamic stresses and material states. An equivalent stress-state parameter was introduced to consider the effect of the loading frequency, enabling the exploration of dynamic loading's influence on the equivalent vibration number (Neq). A comparison between the predicted results and the test data showed that the proposed model could accurately reproduce the cumulative behaviour of the εp of FTCF under different fcyc and qcyc. •Proposed a rate-dependent multistage loading predicted model of εp.•A threshold of fv must exist to maximize the material's resistance to εp.•Load similarity analysis is essential for studying the coupling of freeze-thaw and vibration.