Abstract: A calibration test and method for the relationship between macroscopic parameter and mesoscopic parameter, integrating shear test and particle column collapse test, are proposed based on the multi-phase characteristics exhibited by coal rock particles during collapse body excavation. The analysis of various relationships between macroscopic parameter and mesoscopic parameter in the calibration test is demonstrated using the linear contact model of the Particle Flow Code (PFC). The calibration method is validated through similar simulation and numerical tests of rescue channel excavation in collapsed body. The results indicate that: (1) the shear test and granular column collapse test effectively reflect shear damage of the collapsed body structure under quasi-static flow and energy evolution in fast flow, respectively; (2) The friction coefficient and local damping are key factors in the shear test under quasi-static flow and granular column collapse test under fast flow, respectively, among physical and mechanical parameters; (3) Based on the impact of mesoscopic parameters on macroscopic calibration experiment parameters, we suggest combining phase and weight analyses to efficiently achieve mesoscopic parameter calibration for each phase state by identifying dominant mesoscopic parameters for each phase state; (4) Numerical simulation results of rescue channel excavation in collapsed bodies using shear test and granular column collapse test closely align with similar simulation test results, validating the feasibility of the calibration method that considers phase states in collapsed body research.

Key words: parameter calibration, granular, phase state, shear test, particle column collapse experiment