Effect of microcosmic contact stiffness heterogeneity on macroscopic mechanical parameters of rock

Abstract

The particle flow method is used to build a rock material model formed by the contact between the particles and the geometric constraints. The heterogeneous representation method of rock material components is used to describe the heterogeneous characteristics of the contact stiffness of particles, and a heterogeneous rock material model is established. This numerical model is used to perform numerical simulation experiments on the mechanical properties of rock materials. The influence of the contact stiffness heterogeneity of meso-particles on the macroscopic deformation mechanical properties of rock materials is studied herein. The law of the influence of the contact stiffness heterogeneity on the macroscopic mechanical parameters of rock materials is obtained. In addition, a dimensionless coefficient of the variation of the material parameters is introduced to define the degree of material heterogeneity used to describe the degree of heterogeneity of rock materials. The results show that heterogeneous representation method of the rock material components can be used to describe the heterogeneity of the meso-parameters of rock materials. The macroscopic deformation of the particle flow model of heterogeneous rock materials under load is elastic linear growth at the initial stage and strain-softening deformation failure at the later stage of failure. The deformation parameters of rock materials have a linear relationship with the particle stiffness, while the strength parameters have a quadratic relationship with the particle stiffness. The macroscopic mechanical parameters of rock materials are all weakened by the influence of heterogeneity. The smaller the degree of heterogeneity, the smaller the weakening effect will be. The greater the degree of heterogeneity, the greater the weakening effect.