Rock creep damage model based on the principle of minimum energy dissipation

Abstract

Slow deformation characteristics of rock under sustained stress have a crucial impact on the sustained stability of numerous underground engineering structures. They are understood via a thorough study of the mechanical behavior of rock in the creep process. Considering the energy dissipation phenomenon resulting from the generation and spreading of tiny cracks in rock and the friction between particles, utilizing principles of thermodynamics, the loss of energy is related to the loss of energy of rock, and the quantitative relationship between rock creep damage indicator and energy dissipation rate is established. The results show that the conventional framework is often difficult to accurately describe the whole creep process, while the energy dissipation theory model can clarify the distinguishing features of each stage by analyzing the change of energy. In the transient creep stage, the elastic energy contained in the rock structure is gradually released and accompanied by partial energy dissipation. The experimental values are in good agreement with the anticipated values, particularly during the stage of accelerated creep. That is, damage mechanics model for creep processes established within this investigation can characterize the nonlinear characteristics of its initial, constant, and rapid creep phases. The creep damage constitutive model demonstrates its capability in accurately portraying the creep deformation behavior of sandstone.