Research on Lateral Scale Effect and Constitutive Model of Rock Damage Energy Evolution

The root cause of dynamic disaster such as mine rock burst and tunnel rockburst is that the over-limit of internal energy of engineering rock mass (coal mass) triggers sudden energy release. Rock is inhomogeneous medium composed of mineral particles with various sizes and different shapes after cementation. The damage failure process comes along with the energy assimilation and release. It has important significance on studying the stability. In this paper, lateral scale effect of rock was considered. Firstly, the impact of different aspect ratios on damage mechanics and energy evolution characteristic of rock was discussed by virtue of mesoscopic particle flow PFC2D software platform. After that, the constitutive model of rock damage based on energy features was analyzed. Research result indicates that: lateral scale affects uniaxial compressive strength of rock. With the increasing of aspect ratio, the uniaxial compressive strength of rock decreased and then increased, appearing “V” state; with the increasing of lateral scale of rock, various energies insides rock and energy absorption also appears increasing, but the energy release is unobvious; the fitted constitutive model based on friction energy parameter reflects stress–strain change characteristics of rock better and there is great difference between constitutive model of rock based on boundary energy feature and numerical curve.