Determination of mechanical parameters for soil-rock mixtures based on representative elementary units

The distribution of rock blocks in soil-rock mixtures exhibits significant randomness. Traditional physical experiments and numerical simulations can only obtain mechanical parameters at small scales, which lack representativeness for larger-scale scenarios. This study quantifies mesoscopic features of soil-rock mixtures using MATLAB-based image processing techniques. By integrating the concept of representative elementary units (REUs), the homogenization permissible scale was determined. A mesoscopic REU model was established through finite element analysis, and mechanical parameters (e.g., cohesion, internal friction angle) reflecting macroscopic behaviors were derived via direct shear numerical simulation.