A novel constitutive modelling approach measured under simulated freeze-thaw cycles for the rock failure

In this study, we derived a computational modelling relation between the model parameters and characteristic parameters of rock deformation and failure via total differentials. We construct a damage model of rock under simulated freeze-thaw cycles and loading based on continuum damage mechanics theory that considers the influence of confining pressure and the random characteristics of rock material defects. This model reflects the variation in regulation between the internal mechanism of freeze-thaw damage and selected physical variables, making it more adaptable. We further analyze the evolution of microdamage and induced material mechanical properties of the rock using our proposed model, producing a total damage evolution curve under freeze-thaw cycles and loading that reflects the closure, initiation, propagation and coalescence of internal microcracks, as well as the subsequent appearance of macrocracks and rock failure. As the number of freeze-thaw cycles increases, rock damage intensifies, as demonstrated by the material's deteriorating micromechanical properties. However, in later stages of deformation, both the strain and plasticity of the rock increase. With increasing confining pressure, rock damage and the damage accumulation rate, peak damage evolution ratio and descending segment after the peak decrease which manifest in the enhanced resistance of the rock to failure and increased macroscopic plastic deformation. Finally, we perform triaxial compression tests of rock under freeze-thaw cycles to validate our model. The macroscopic rock deformation and failure predicted by our model's damage characteristics analysis are consistent with our experimental result.

Automated summary

In this study, a computational model was developed to analyze rock deformation and failure characteristics under freeze-thaw cycles and loading, considering the impact of confining pressure and material defects. The model successfully reflects the internal mechanism of freeze-thaw damage and selected physical variables, demonstrating adaptability. The model also predicts an evolution curve of total damage, showing the closure, initiation, propagation and coalescence of internal microcracks, as well as rock failure mechanisms.