Particle flow study on the microscale effects and damage evolution of sandstone creep

The creep damage of hard rock is significantly influenced by its microscopic parameters and pore structure. To explore the correlation between the macroscopic creep characteristics and microscopic properties of sandstone, the construction method of Clumps with random geometry (CRG) that can simulate the creep movement of minerals was proposed. Through seepage corrosion tests and uniaxial creep tests, a rock porous creep model was established, and the CRG model was used to investigate the evolution pattern of rock fracture and the relationship between macro and micro parameters. The results demonstrate that the creep parameters of red sandstone are significantly affected by its microporosity. When particles range from 0.05 to 2 mm, the instantaneous and creep mechanical properties of the CRG model are strongly dependent on contact parameters and porosity, but less sensitive to particles size. The simulation based on CRG is in good agreement with the laboratory tests, with a certain proportional relationship existing between the microscopic contact parameters of the numerical model and the macroscopic creep parameters of the laboratory test.