Energy evolution mechanism and failure criteria of jointed surrounding rock under uniaxial compression

The object of this article is to investigate the energy evolution mechanism and failure criteria of cross-jointed samples containing an opening during deformation and failure based on the uniaxial compression test and rock energy principle. The results show that the energy evolution characteristics of the samples correspond to a typical progressive damage mode. The peak total energy, peak elastic energy, and total input energy of the samples all first decrease and then increase with an increase of half of the included angle, reaching their minimum values when this angle is 45 degrees, while the dissipated energy generally increases with this angle. The existence of the opening and cross joints can obviously weaken the energy storage capacity of the rock, and the change in the included angle of the cross joint has a great influence on the elastic energy ratio of the sample before the peak stress, which leads to some differences in the distribution laws of the input energy. The continuous change and the subsequent sharp change in the rate of change in the energy consumption ratio can be used as the criteria of the crack initiation and propagation and the unstable failure of the sample, respectively.