Influence of pore-like flaws on strength and microcracking behavior of crystalline rock

Pore is a common type of microdefect or flaw in rock or rock-like material. Predicting the influence of pore-like flaw on the deformation, strength, and failure behavior of a brittle material is a topic of great interest in the field of geomechanics and geotechnical engineering. In this study, the influences of a group of two-dimensional circular pore-like flaws with varied number, position, and size on the strength and deformation behavior and the associated microcracking process of crystalline rock is numerically investigated by using a grain-based modeling approach. The results reveal that the simulated strength and deformation properties, and the temporal and spatial microcracking process are significantly influenced by the aggregation of a group of pore-like flaws in the model. Due to local stress amplification, the uniaxial compressive strength (UCS) and elastic modulus are found to decrease as the pore number (ie, porosity) gradually increases in the model. The microcracks mostly initiate at the top and bottom of the pore-like flaws, and tension zones generally form around these assembled pores in the loading direction. The stress magnitude in the model, which generally decreases with the increase of porosity in the model, is obtained and quantitatively analyzed. As compared with regularly assembled pores, randomly distributed pores are found to cause much more uniformly distributed stress and smaller tension zone in numerical models. The position of pore-like flaws has been shown to have a negligible influence on the strength and deformation behavior, while the simulated UCS is found to progressively increase with increasing radius of the pore-like flaw.

Automated summary

The aggregation of a group of pore-like flaws significantly influences the strength, deformation properties, and microcracking process of crystalline rock. As the number of pores increases, the uniaxial compressive strength and elastic modulus of the rock decrease. Randomly distributed pores cause more uniformly distributed stress and smaller tension zone in numerical models compared to regularly assembled pores. The position of pore-like flaws has negligible influence on the strength and deformation behavior, while the UCS increases progressively with the radius of the pore-like flaw.