Uniaxial failure test and simulation of plate with circular hole containing single crack

In order to study the crack propagation of a circular perforated plate with a single crack under uniaxial compression with different crack lengths and crack angles, rock-like specimens with a circular hole diameter of 15 mm are made, in which the crack lengths are 7.5 mm, 12.5 mm and 17.5 mm respectively, and the crack angles are 0°, 15°, 30°, 45°, 60°, 75° and 90° respectively, the uniaxial compression test is carried out by DDL-200 testing machine, the particle flow discrete element software PFC is used to further study the stress state and crack propagation of the specimen.The results show that appropriate prefabricated cracks can improve the compressive strength of specimens, with the increase of crack inclination, the stress concentration of the specimen gradually transits from the crack tip to the hole edge, making the initiation and propagation of new cracks transfer to the hole edge, at the same time, larger crack length and smaller crack inclination make the specimen have larger tensile area and more uneven stress distribution.In addition, the stress intensity factor decreases first and then increases with the increase of crack inclination, the crack corresponding to the lowering stage belongs to the closed crack, and the crack corresponding to the rising stage belongs to the open crack.The research results can provide some reference for roadway support and roof cutting pressure relief in underground engineering.