Numerical Experiments on Triaxial Compression Strength of Soil-Rock Mixture

Abstract

Soil-rock mixture is a kind of unfavorable geologic material, and it is composed of low-strength soil particles and high-stiffness rock blocks. Mechanical properties of soil-rock mixture were controlled by the internal mesoscopic medium, thus resulting in great difficulties of determination of mechanical parameters. In this paper, influences of rock content, mesoscopic features, and random distribution of mixture in soil-rock mixture on its shear strength were discussed through discrete element numerical simulation of the laboratory triaxial test. Results demonstrated that, with the increase of rock content, the internal friction angle of soil-rock mixture increased continuously, while the cohesion of soil-rock mixture decreased firstly and then increased. The stress-strain curve belonged to a nonlinear hardening type, which was close to soil characteristic. However, the shear strength was affected by mesoscopic medium of mixture particles significantly, resulting in the strong discreteness of strength, and only by large amounts of data statistics can we get a better regularity of strength. The research results can provide references to determine mechanical parameters of soil-rock mixture.