Research on Microscopic Evolution Laws of Sandstone Deformation and Failure Based on the Particle Discrete Element Method

The fracture of sandstone is closely related to the condition internal microcracks and fabric micrograin. macroscopic mechanical property depends on its microscopic structures. However, it difficult obtain law microcrack growth under loading by experiments. A series models were established with particle flow code 3D (PFC3D) based triaxial experiment results sandstones. experimental numerical simulations natural saturated sandstones different confining pressures implemented. We analyzed evolution rock deformation development from a view. Results show that although are pressures, same. That is, number increases slowly in initial stage then exponentially. shear cracks more than tensile cracks, proportion increase pressure. cracking strength 26% 27% peak strength, respectively. Under low pressure, total sample 20% strongly scattered chain barely seen. With effect water reduced distribution strong even uniform. In other words, pressure mainly affects force chain, irrespective state rock, or saturated. research reveal control mechanism crack friction stress states slope reservoir area provides basis for evaluating stability mass predicting occurrence geological disasters.