Validation and calibration of soil parameters based on EEPA contact model

The determination of parameters is a key issue in discrete element simulation and controls the accuracy and reliability of the simulation results. In this paper, a sandy loam soil with three water contents is studied and soil particles based on the EEPA model are modelled in three shapes (spheres, columns and Triangular pyramid) to accurately represent the actual soil particle. The sensitivity of the input parameters in the EEPA model is investigated by the Plackett–Burman test. The results show that the coefficient of static friction, coefficient of rolling friction and surface energy between soil particles have a highly significant effect on the angle of repose, and the coefficient of restitution has a significant effect on the angle of repose. The sensitivity parameters are calibrated by the central combination test, and the optimal combination of parameters is obtained. The accuracy of the parameters calibrated is validated by comparing the simulation results of the direct shear test with the actual test results. Therefore, the parameters calibrated satisfy both the flow and mechanical properties of the particles.