DEM analysis of 2D fibre-reinforced granular soils

Laboratory experimental tests of sand reinforced with discrete random flexible fibres show that fibre reinforcement could be an effective technique for improving their strength and deformation characteristics. The behaviour of fibre reinforced sand is influenced by many factors such as density and stress level, fibre type, content and orientation. A two dimensional DEM (Distinct Element Method) biaxial compression simulation of mixtures of sand and fibres is applied to understand how randomly distributed flexible fibres generate a bond within the soil and affect the kinematics of the granular matrix. Sand particles are modelled by rigid disks with conventional contact elements in DEM. The fibre element is modelled by connecting small circular particles with a bond contact algorithm, where the strength of the bond is fairly high. The DIEM analysis show encouraging results concerning the use of DEM for the understanding oldie interaction mechanism between fibres and matrix and give very useful insight on how the presence of fibres affect the kinematics of the granular matrix. It is clearly shown that the highest tensile stresses are mobilized on fibres oriented towards the minor principal strain direction. Moreover, local micro fabric and local structural rearrangement are important as they can affect the interaction mechanism.