Calibration of DEM material parameters to simulate stress-strain behaviour of unsaturated soils during uniaxial compression

Abstract

Discrete element method (DEM) is an appealing technique to simulate soil deformation. However, the calibration of the material parameters in the model remains challenging due to the high computational cost associated with it. In this study, the stress-strain relation of 125 unsaturated soil samples was simulated using DEM and material parameters were calibrated with Kriging. The Young's modulus and friction angle were found to be the most sensitive DEM material parameters, and they had a significant correlation with the bulk density, clay content and water content of the undisturbed soil samples. The DEM simulation showed that the deformation process was a combination of elastic and plastic processes, also at low stresses. Further improvement such as the coupling with (and calibration of) a fluid dynamics model might allow to more accurately simulate the dynamic behaviour of unsaturated soil compression.