LAUSR

Abstract Triaxial compression experiments on dry Ottawa sand are numerically simulated using Finite Discrete Element Method (FDEM) in conjunction with X-ray CT imaging. A novel framework is introduced and validated where particle shape is captured in FEM simulations using shell elements for simulating triaxial boundary value problem. The proposed approach is well suited for load cases with low/intermediate confining pressures where particle breakage is negligible. The numerical model allows for grain deformation as well as robust particle contact fabric evolution for the realistic grain morphology. For this research, the confining latex membrane is modelled as hyper-elastic material to provide flexible boundary condition on the lateral surface of the cylindrical sand specimen. Volume change measurements are obtained directly based on the convex hull of an assembly of sand grains, with no contributions or associated errors from latex membrane effects. In this paper, we attempt to explore the FDEM modeling aspect from different perspectives considering macroscale and microscale response. The influence of the frictional and frictionless boundary on the strength deformation response and localization in displacement field is discussed. Furthermore, sensitivity of mesh refinement, interparticle friction coefficient and critical shear stress on strength and volume change response is quantified.