From Micromechanics Particle Simulation to Macroscopic Experimental Phenomena of Cross-Anisotropic Soil Elasticity

Micro-mechanisms in the analysis of elastic shear stiffness were investigated by the simple multi-scale approach incorporating with the discrete element simulations. The stress-level dependent elastic stiffness and the cross-anisotropic elasticity were focused to characterize the experimental soil elasticity. To capture the micromechanical response of a granular assembly, the discrete element simulations with 10,000 spherical particles were conducted. The small-strain cyclic shear tests were simulated to obtain the elastic shear stiffness. The regression on the elastic shear moduli yields the power relationship between the elastic stiffness and stress components. The sums of the exponent are consistently around 0.35. The micro to macro scale analysis of the elastic properties was attempted. The apparent similarity between macroscale and microscale constitutive equations determines the macroscale parameter of the exponents. The simple multi-scale approach was confirmed by the numerical simulations which result in the similar value of the exponent to that in the Hertz's contact law.