Integrating RFPA and DEM in Adaptive RDFA Modeling of Rock Fracturing Process

This paper proposes a hybrid rock discrete fracture analysis (RDFA) method that combines the rock failure process analysis (RFPA) method and discrete element method. Based on the continuum mechanics, statistical damage mechanics, and contact theory, RDFA offers a comprehensive framework to simulate the continuous–discontinuous behaviors encompassing fracture and fragmentation within rocks. Through the newly developed nodal updating scheme, RDFA enables adaptive node adjustments at critical crack tips once the strength criteria is met, effectively capturing the initiation and propagation of zero-thickness cracks. Notably, RDFA accommodates the heterogeneity of rock masses, allowing for the synchronized consideration of localized damage and fine-crack evolution. RDFA was calibrated by modelling the Brazilian splitting tests on rock, aligning closely with the analytical solutions. Subsequently, the rock specimens containing single or double flaws were uniaxially compressed. The results showed that when the flaw inclination angle α increased from 0° to 60°, the distance between the initiation position of cracks and the flaw tip decreased exponentially; the crack initiation stress first decreased and then increased with the growth of α, and when α = 30°, it reached the minimum value of 15.2 MPa. RDFA can effectively replicate rock fracturing processes, failure modes, and critical strengths across diverse inclinations.