Effect of heterogeneity of particle properties on the mechanical properties of sandy soil materials

Abstract

The random arrangement of particle composition or the heterogeneity of the particles' inherent properties is what causes the variability of mechanical parameters in sandy soils. Combining the discrete element method with random field theory, a random discrete coupling modeling method is refined, in which a rolling resistance contact model was used to take into account the rolling friction characteristics of sand soil particles. Four random discrete element models (RDEM) are developed for typical working situations taking into account the two random field factors, i.e., the coefficient of variation and fluctuation range. The Monte Carlo method is employed to simulate the triaxial RDEM, and the stress-strain relations, parameters of strength and deformation are analyzed. The effects of the coefficient of variation (Cov) and fluctuation range (δ) on the variability of mechanical characteristics are studied. The results show that the mean shear modulus G, peak friction angle φp, and critical friction angle φc of random heterogeneous samples decline while the mean Poisson's ratio μ increases as the Cov increases. The mean values of parameters of deformation and strength of random heterogeneous samples eventually approach those of homogeneous samples as the δ increases.