Evolution law of self-suppression of peak energy of single jointed sandstone

Exploring the influence of joints on the damage and failure law of rock mass from an energy perspective can provide a reference for the stability analysis of engineering rock mass.Using the laboratory rock mechanics test and digital image correlation method and PFC,based on rock energy theory, the me-chanical characteristics of single joint sandstone under uniaxial compression and the joint dip effect and joint length effect characteristics of the energy self-inhibition evolution model were studied.The research established a self-inhibited evolution model between the pre-peak elastic strain energy and axial strain of jointed sandstone, and discussed the influence of joint length, joint dip and confining pressure on the self-inhibited evolution of jointed sandstone pre-peak macro and meso energy.The research shows that the macro and meso energetic energy accumulation process of jointed sandstone before the peak can be char-acterized by its energy self-inhibition evolution model, which fits well with laboratory results and numerical simulation results.From the perspective of the evolution of model parameters, the characteristics of joint dip effect and joint length effect that affect the mechanism of energy accumulation and transformation with or without considering the self-inhibition effect are both synchronous and competitive, but the mechanism of inhibiting energy transformation plays a decisive role in the final result of pre-peak energy accumulation.High confining pressure conditions will weaken the self-inhibition of the meso energy accumulation process in front of the jointed sandstone.Under the same confining pressure energetic, the macro and meso energy self-inhibition of the jointed sandstone in front of the peak first increases and then weakens with the increase of the joint dip.The accumulation rate first decreases and then increases, and the energy storage limit at the corresponding peak point first decreases and then increases.As the length of the joint increases, the macro and meso energy self-inhibition of the jointed sandstone in front of the peak gradually increases, and the energy accumulation rate gradually decreases, the energy storage limit at the corresponding peak point gradually decreases.