Effect of Joint Angle on the Failure Behavior of Rock-Like Specimens Under Unilateral Restrained Compression

Studying the stability and failure modes of surrounding rock with different joint angles has important guiding significance for the subsequent mine support design. This study based on self-made mold, 3D printing joint, digital image correlation (DIC) technology, acoustic emission technology and Particle flow code in two-dimensional to systematically examine the failure process, failure modes and mechanism of specimens with various joint angles under unilateral restrained compression. The findings demonstrate that the change in joint angle has an impact on the mechanical properties of the specimen under unilateral restrained compression, including peak strength, strain, and elastic modulus, as well as crack propagation (wing crack, secondary crack). The specimen's principal mode of failure under the influence of unilateral restrained compression is tensile failure, which get a certain explanation by the calculation results and RA-AF (Rise time/amplitude and ringing count/duration) value. The orientation of the crack's initiation and propagation can be seen clearly with DIC technology, the numerical model and the experimental results are also relatively consistent. The failure degree of specimens with different joint inclination angles is different. The degree of failure of specimens with 30° joint inclination angles is higher, and the specimens with 90° joint inclination angles have higher ability to resist deformation.