Integrating RFPA and DEM in Adaptive RDFA Modeling of Rock Fracturing

This study proposes a hybrid rock discrete fracture analysis (RDFA) method by combining the rock failure process analysis (RFPA) method and discrete element method (DEM). Depending 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 under the fulfillment of strength criteria, effectively capturing the initiation and propagation of zero-thickness cracks. Notably, RDFA accommodates the heterogeneity to rock masses, allowing for the synchronized consideration of localized damage and fine crack evolution. RDPA was calibrated via the Brazilian splitting test, aligning favorably with the analytical solutions. Then, rock specimens containing single or double flaws were uniaxially compressed. The results show that when the flaw inclination angle α increases from 0° to 60°, the distance between the initiation position of cracks and the flaw tip decreases exponentially; the crack initiation stress first decreases and then increases with the growth of α, and when α = 30°, it reaches the minimum of 15.2 MPa; RDFA can effectively replicate rock fracturing processes, failure modes, and critical strengths across diverse inclinations.