Particle Flow Simulation of Failure Process of Defective Sandstone under Different Intermediate Principal Stress under True Triaxial Action

In order to explore the mechanical response characteristics of fractured sandstone under true triaxial different medium principal stresses, matdem particle flow software was used study characteristics, fracture mechanism and damage evolution specimens conditions 30 MPa, 40 MPa 50 respectively. The simulation results are verified by test. show that stress, increase stress is beneficial strength sandstone. degree specimen increases with intermediate finally interlacing macroscopic cracks formed. When perpendicular strike, mode plane compression mainly shear failure, accompanied tensile failure. With increasing fractal dimension significantly deepens. Combined test results, rationality proved.