Abstract: The key to the numerical simulation of the particle flow is to reveal the relationship between macro and meso mechanical parameters correctly and determine the meso parameters reasonably. The numerical tests of soft soil triaxial compression were established by the PFC3D software. Based on the results of macro-triaxial tests, the characteristic relationship between macro-meso parameters of the Burgers contact model was studied throughout the orthogonal test design. The results show that the stiffness E_k and E_m of Hooker spring are the significant factors that affecting the deformation characteristics of the soft soil that mainly control the secant deformation modulus E₅₀; The friction factors f and E_m are significant factors that affecting the strength characteristics of the soft soil, which mainly controlling the maximum shear strength qf; The E₅₀ is negatively correlated with Ek and positively correlated with Em, q_f is negatively correlated with Em and positively correlated with the friction factor f. A linear regression relationship with macroscopic parameters as dependent variables and meso parameters as independent variables was established. The results of the inversion were used to perform the triaxial compression numerical tests and obtain macroscopic mechanical parameters. The errors were less than 10% compared with laboratory test results.

Key words: Particle Flow Code, Burgers Contact Model, Orthogonal Tests, Triaxial Compression Tests, Macro and Meso Parameters