Development and calibration of discrete element model for layered gravel soils in forested areas

In this paper, a Discrete Element Method (DEM) model is developed to accurately simulate the interaction between forestry machinery vehicles and forest-layered gravel soils. The soil grains in the DEM model are simulated as spherical particles, while the gravel is represented by nine types of non-spherical particle clusters based on the actual gravel content, size, and shape. The DEM model parameters are calibrated through the indoor angle of repose (AOR) and triaxial shear tests, followed by statistical calibration using Plackett-Burman, Steepest Ascent, and Box-Behnken experiments. The values of the optimal DEM model parameters are determined based on the obtained quadratic regression analysis. Finally, the MED model accuracy is verified by comparing indoor test results with the DEM simulation outputs and mathematical predictions. The results revealed that the DEM model simulated curves closely match the measured values, indicating good agreement.