Numerical method for the triaxial test of granular materials based on computational contact mechanics

Abstract Traixial test is a common method for the study of the mechanical behaviors of granular materials. And, the interaction between the membrane and particles will greatly influence the test results. In this paper, computational contact mechanics method is developed for the simulation of sphere-sphere and sphere-membrane contacts in triaxial test. In both algorithms, the contact state and distance functions are determined according to the geometric information of the spheres instead of the finite element mesh. Two benchmarks have been used to validate the proposed algorithms, and the results showed that the sphere-sphere and sphere-membrane interactions were accurately and stably simulated. Furthermore, the size of the spherical particle elements has minor influence on the numerical results and therefore, it can be used for the study of the granular mechanics with larger number of particles. Finally, the consolidation process of a triaxial test is studied and compared with the laboratory tests, which also shows that the algorithm can not only better simulate the membrane penetration process but also the meso mechanics of the granular materials.