Influence of temperature on the transformation and self-control of energy during sandstone damage: Experimental and theoretical research

The surrounding rock in tunnelling engineering and coal mining will sometimes be exposed to high temperature. Rock failure is the result of energy dissipation, and the study of the evolution and transformation behavior of energy is of great significance for the in-depth understanding of the deformation and failure of rock after high temperature. This study analyzed the intrinsic connection between mechanical properties and acoustic emission (AE) energy under temperature effect. Based on the energy dissipation and release theory, the distribution and transformation of energy was analyzed, and the energy self-incentive and self-inhibition (EII) model was further established. The main findings are that temperature effect affects the confidence interval trend and the value of AE energy rate, which is related to the change in mechanical properties. The ability of sandstone to store elastic strain energy after exposure to high temperature is independent of the mechanical properties. In this study, the ratio of dissipated energy to elastic energy is used to characterize the stable state of the sandstone system, which can be used as the energy indicator of rock failure precursor. During the absorption, storage, and release of energy before the peak stress, there exists self-incentive and self-inhibition of energy (control behavior).