Uniaxial accelerated creep constitutive model of rock considering damage and hardening

In view of the lack of understanding and description of nonlinear characteristics and accelerated creep deformation law in current rock creep research, and the difficulty of existing models to fully reflect the coupling effect of damage and hardening in creep process, this study aims to construct a creep constitutive model that can accurately describe these complex mechanisms to support the stability control of surrounding rock and the prevention and control of geological disasters in underground engineering. Based on Rabotnov creep damage law, combined with hardening and damage theory, a uniaxial accelerated creep constitutive model considering the dual effects of damage and hardening was constructed by combining theoretical derivation with model verification. The results show that the damage variable of rock under failure stress increases slowly with time-suddenly increases and approaches to 1 when it is close to failure. The hardening function verifies the objectivity of the hardening phenomenon in the stable stage. The model can accurately describe the creep behavior under different stresses (the correlation coefficient is higher than 0.90) and predict the deformation law under failure stress well. Finally, it is concluded that the model can effectively make up for the shortcomings of the existing model. It provides a reliable theoretical tool for understanding the key laws of rock creep, and also has important practical value for the stability evaluation of surrounding rock in underground engineering and the prevention and control of geological disasters.