Micromechanical and energetic investigation of shear behavior of sand-rubber mixtures: Effect of rubber content and normal pressure

This paper presents a numerical investigation into the effect of rubber content and stress level on the mechanical behavior and energy transformation of sand-rubber mixtures (SRMs) under simple shear condition using a multibody meshfree method. The results reveal that the presence of rubber particles reduces interparticle contact forces, inhibits the formation of strong force chains, and promotes a more uniform force network. The input work is predominantly transformed into strain energy, damping energy, and slipping energy, with the transformation mode heavily dependent on the rubber content and normal stress, which govern the compressibility of SRMs in relation to rubber particles' deformability and the frictional dissipation capacity associated with interparticle friction conditions. The incorporation of rubber particles also enhances the strain energy storage capacity, which is attributed to the restricted particle slipping and rolling behaviors, as well as the diminished particle surface asperity due to rubber particle deformations. These findings provide insights into the macro- and micro-mechanical behavior of SRMs, bridging the gap between the energy transformation and the mechanical response of SRMs, and contributing to the development of more efficient and sustainable geomaterials.