Modelling Triaxial Tests on Fibre-Reinforced Sands with Different Fibre Orientations Using the Discrete Element Method

Abstract

Fibre-reinforced soil has been widely applied as a composite fill material in geotechnical engineering. In this study, triaxial tests of fibre-reinforced specimens with different fibre orientations were performed employing the discrete element method. The approach enables an investigation of some significant micromechanical properties, including the contact orientation distribution, coordination number, particle displacement field, and contact sliding fraction. From the discrete element method (DEM) perspective, fibre orientation affects the contact force distributions and the load-bearing mechanism for this mixture system. More horizontal fibre particles participate in supporting the strong force chains compared with the vertical and random fibres. Fibre orientation also affects the pattern of displacement fields, which shows that horizontal fibres can limit the formation of localised shear bands. Horizontal fibres also cause the largest increase in the normal contact force acting on the fibre-sand interface and the coordination number of the sand-fibre contact type, which leads to an increase of sliding friction between fibres and the sand matrix. The majority of horizontal fibres could also produce tension during triaxial compression, leading to a more effective reinforcement. The results from this study could contribute to improving our knowledge of mechanical behaviours of sand-fibre composites.