An Integrated 3D DEM Modeling Process for Bimrocks Considering Post-Peak Behavior and Block Breakage

Bimrocks, a complex rock mass commonly found in geotechnical engineering, are often analyzed through the discrete element method (DEM) to understand their mechanical behavior from both macro and micro perspectives. However, there is limited research addressing the post-peak behavior of bimrocks, particularly in terms of the uniaxial compression stress–strain curve and failure characteristics, with many studies overlooking the complex nature of their post-peak behavior. This study proposes a comprehensive method for constructing three-dimensional (3D) numerical samples of bimrocks and selecting appropriate parameters, focusing on accurately capturing both the post-peak curve shape and failure characteristics. By combining laboratory tests with CT scanning techniques, numerical samples with structures matching those of the physical samples are created, addressing the issue of block stone breakage in traditional discrete element simulations. The study introduces the selection criteria for matrix and block stone parameters and analyzes the microscopic factors influencing the post-peak curve and failure characteristics. Results indicate that the damping coefficient and loading rate are crucial in shaping the post-peak curve, with complex curves requiring multiple damping coefficients. Additionally, the radius multiplier influences crack propagation direction, while the strength ratio affects crack penetration and secondary cracking, with these factors being dependent on the matrix strength.