An efficient method for determining DEM parameters of a loose cohesive soil modelled using hysteretic spring and linear cohesion contact models

Abstract

Appropriate discrete element modelling (DEM) parameters are essential for accurate prediction of soil properties and disturbance. This study aims to provide an efficient method for accurately determining DEM parameters of a loose cohesive soil in a range of soil conditions. DEM parameters of the loose cohesive soil modelled using hysteretic spring and linear cohesion contact models were determined by a combination of Plackett–Burman, steepest ascent and central composite tests. The accuracies of DEM models developed under different soil moisture contents (0.27–22%) were evaluated using slumping angle of repose test and funnelling angle of repose test. Heap angles under different soil moisture contents decreased quadratically with time with determination coefficients ranging from 0.750 to 0.969. For the given soil, friction or rolling friction coefficient of soil–soil changed with a cubic function as moisture content increased. Similar coefficients of friction (0.23–0.25) and rolling friction (0.038–0.049) of soil–soil were found for moisture contents from 12 to 22%. Based on ANOVA outputs, soil properties tested were significantly affected by soil moisture content at p < 0.05, including angle of repose (AOR), releasing time, yield strength of soil and coefficients of friction and rolling friction of soil-steel. Low relative errors (<2.8%) were found for simulated AORs using developed soil DEM models under different soil moisture contents. Simulated releasing time agreed well with high-speed video measurements. The suggested method has good potential to accurately determine DEM parameters for loose cohesive soils in a range of conditions.