Damage characteristics and fracture evolution laws for prefabricated hole rock specimens

A significant number of karst mines are present in the southwestern region of China. The dissolution of rock within these mines has resulted in the formation of numerous hole defects within the rock body. To investigate the mechanisms of rock destruction under stress conditions, uniaxial compression tests are conducted using rocklike specimens. These tests examine the mechanical properties of rock-like specimens with varying shapes and locations of holes. The rupture evolution process of the specimens is monitored and analyzed using digital image- related technology. Finally, numerical simulation methods are employed to invert the simulation of the destruction characteristics of specimens with pore defects under unidirectional stress damage. Ultimately, numerical simulation is employed to reverse engineer the damage characteristics of specimens with hole defects under unidirectional stress damage. It was determined that specimens containing holes exhibited a notable decline in strength. When the holes were situated in the upper, middle, and lower regions of the specimens, the compressive strength was observed to diminish by 29.80%, 46.77%, and 30.85%, respectively, in comparison to the intact specimens. The compressive strength of the complete specimen exhibited a notable decline, reaching 31.90%, 35.50%, and 40.31% reductions when the holes were shaped as spheres, squares, and polygons, respectively. This observation suggests that the strength of the specimen was most susceptible to the location of the holes in the central region and the shape of the holes as polygons. The presence of holes results in the maximum principal strain being concentrated in the vicinity of the holes. Consequently, the location of crack development often coincides with the strain concentration area. This test result can be utilized as a precursor to warning of specimen damage.