Meso-mechanism Research on Mechanical Properties of Rock-like with Two Fissures in Brazilian Test

The tensile strength is one of most significant parameters for rock, while few studies have been reported on the rupture mechanism regarding Brazilian test in rocks containing two fissures. In this work, the rock-like materials were adopted to prefabricate Brazilian disc specimens containing two prefabricated fissures. Based on the X-ray computed tomography technology and Particle Flow Code in 2 Dimension, the influences of different fissure dip angles on strength, deformation, fracture and other mechanical properties in Brazilian test are investigated. The research shows: When the dip angle of the upper fissure is 0°, with the dip angle of the lower fissure grows from 0° to 90°, the tensile strength decreases rapidly and then fluctuates slightly, while the elastic modulus is not affected; when the dip angles of the two fissures are comparable, as the angle between the two fissures gradually increases, the tensile strength decreases first and then increases, and the elastic modulus shows a monotonic growth, but the strain corresponding to the peak stress gradually decreases. In terms of the rupture mechanism, few shear cracks are developed from the fissure tip, while the micro-cracking activity is dominated by tensile failures inclined to the loading direction, which further penetrate across the bulk specimen.