A bonded-particle model for cemented sand

Abstract

We propose an extension of the Discrete Element Method for the numerical simulation of cemented sands, in which spherical particles are bonded together by elastic beams connecting the centers of the spheres. The parameters of this model are the strengths and stiffnesses of the bonds and particles. For small strains, the elasticity of the bond element is equal to the well-known linear finite-element Timoshenko beam element with reduced integration. The finite rotations are represented by unit quaternions. An efficient way to compute relative rotations and to decompose them into their components is presented.The results of triaxial compression tests on artificially cemented sands are used to verify that the model can capture the macroscopic behavior of such materials. The results show that peak stress mainly depends on the strength of the bonds and the number of initially bonded particles in the material. Results of triaxial tests with different cement contents are reproduced by the analysis. An important parameter of the model is the strength difference between tension and compression of the bond element. This property controls the influence of the confining pressure on peak strength. In the future, the model could be adapted to other types of bonded materials like asphalt or rock.