Discrete element modelling of the mechanical behaviour of a sand-rubber mixture containing large rubber particles
Sand-rubber mixtures (SRMs) are newly developed geomaterials that have been widely applied in geotechnical engineering. However, the precise particle-level mechanical properties of SRMs are not yet fully understood. The present study conducted numerical simulations of triaxial tests of SRM samples containing large rubber particles employing the discrete-element method. This method allows the tracking of many important microstructural quantities, including the distribution of contact normal orientations, coordination number, particle displacement, particle sliding, and rolling during shearing. Numerical simulations showed that the contact normal anisotropy along the loading direction is clearly weakened by the addition of rubber particles. Rubber-rubber contacts are found to mainly participate in weak force networks. With an increase in the rubber content, rubber particles gradually participate in strong force chains, resulting in a more homogeneous magnitude of contact forces in the SRM. It is also observed that the rubber inclusions obviously change the pattern of strain localisation in the displacement field, indicating that rubber particles can prevent the formation of shear bands. The addition of rubbers also restrains the particle rearrangement effect by restricting interparticle rolling and sliding motion on a microscale. These findings expand the current understanding of the mechanical behaviours of SRMs.
Keywords: Sand-rubber mixture, Discrete-element method, Soft-rigid mixture, Particle-scale behaviour, Mechanical response,