Abstract: To address the challenges of coring in deep, hard, and brittle formations, such as difficulties in obtaining complete core samples and the high cost of indoor rock mechanics experiments, a numerical approach is employed. A multi-component digital core model, structured on a Voronoi polyhedron framework is established according to mineral composition content. An equivalent modulus method is proposed to dynamically adjust the mechanical properties of minerals under triaxial compression conditions. The digital core's triaxial compression process is simulated, yielding fracture patterns, stress-strain curves, and elastic modulus values, which align with indoor experimental results. A comparative analysis of the effects of triaxial pressure on the overall rock structure and mineral grains is conducted, focusing on damage and stress distribution. The findings reveal that the impact of triaxial pressure on mineral grains varies depending on the type and spatial distribution of minerals, while also inhibiting crack propagation in the rock. This approach and the results provide new insights into studies on the mechanical and fracture behavior of digital cores, and effectively simulates rock mechanics responses and fracture patterns under complex geological conditions, and offering technical support for solving the coring challenges in deep hard and brittle formations.

Key words: digital core, triaxial compression, rock mechanics, crack propagation, stress distribution