Numerical investigation of cracking behaviors in rock with interrupted double cross fractures under Brazilian splitting

The stability of underground engineering in coal mines is influenced by the tensile properties of fractured rock masses. In this study, the finite element method with embedded zero-thickness cohesive elements (FEM-CZM) was employed to conduct numerical simulations of Brazilian splitting tests on specimens containing double intersecting pre-existing fractures, and the influence of fracture parameters on crack propagation characteristics was analyzed. The results indicate that the tensile stress zones are primarily distributed around the pre-existing fractures, while the compressive stress zones are mainly located at the central top and bottom of the specimen. The tips of the pre-existing fractures serve as stress concentration zones, and tensile failure is the primary cause of crack initiation. With the increase in the rock bridge inclination angle and main fracture inclination angle, both the number of cracks and the crack area show an upward trend. As the rock bridge length increases, the number of crack initiations and the crack area initially decrease slightly and then increase significantly. As the angle between main and secondary fractures increases, the number and density of cracks increase. The research findings provide a more scientific theoretical basis and design guidance for engineering stability assessment and disaster prevention.