Abstract: The stress analysis of the circular hole is one of the classical problems in the mechanics, and as well in tunnel and roadway engineerings. With the development of fracture mechanics, the research on the hole with cracks has been deepened. However, previous studies mainly focused on the two-dimensional problems or holes with surface cracks, and there are few reports on the hole problems with three-dimensional internal cracks. Firstly, based on the 3D-ILC method, the deep internal cracks were generated in brittle materials containing circular holes. The uniaxial compression tests were performed on the specimens with internal cracks. The experimental results are compared with the existing literatures, and the theoretical and numerical simulation studies are carried out. Results show that: 1) Compared with traditional methods, the 3D-ILC method has more realistic crack characteristics and lays a foundation for solving the three-dimensional internal crack problem in fracture mechanics. 2) The main crack shapes of intact specimens are the primary crack and remote crack. 3) For the specimenes with internal cracks, the main crack shapes are the wing crack, secondary crack, anti-wing crack, anti-secondary crack, vertical torsional crack and primary crack. 4) The ultimate failure load of the specimen with cracks is 76.49% of the intact specimen, while the crack initiation stress is 96.72%. 5) The simulation results are in accordance with the experimental results. This study provides an experimental basis for the corresponding theoretical research.

Key words: 3D-ILC, fracture mechanics, crack propagation, problem with circular hole, brittle solids, 3D internal crack