Particle Flow Simulation of Anisotropic Mechanical Properties of Cracked Rock Mass

In order to study the anisotropy caused by crack propagation and evolution of rock mass, a particle flow model reflecting the anisotropic mechanical characteristics of rock initial isotropic materials is established, and uniaxial compression tests of rock samples with different crack inclination angles are carried out. Based on the failure mode and stress–strain curve characteristics of the sample, the anisotropic characteristics of pre-existing cracks granite are analyzed by means of theoretical calculation of fracture mechanics and numerical simulation. The results show that the dominant crack angle corresponding to the fracture strength of rock samples is 24°~30°, and these directional cracks have guiding and promoting effects on crack propagation. The crack initiation stress level and peak stress of rocks with pre-existing cracks both show a trend of decreasing first and then increasing with the inclination increase of cracks. The compaction process of cracked granite samples lasts for a long time, and the compression deformation is mainly the deformation of fractured surface. The macro fracture surface formed by the connection and penetration of pre-existing cracks and newly-generated cracks is consistent with the main crack plane. The anisotropy of rock elastic modulus changes little, but the directivity of peak compressive strength is obvious. When the crack inclination angle is 45°~60°, the strength of rock specimen is the lowest, which has the greatest influence on the anisotropy of cracked rock mass.