To improve the efficiency of the macro-meso parameters calibration of the triaxial test in the DEM

a new method

iterative calibration

is proposed. By using a fish language program

the numerical simulation of the triaxial test in the PFC3D software is achieved. Based on the contact bond model

the triaxial test of sand is simulated

and the validity of the iterative calibration method is verified. The calibration proves that both the size of the particle stiffness and the ratio of the particle stiffness affect the size of the partial stress

particle normal stiffness affect the initial Young's modulus

the effect of the friction coefficient on the partial stress is depended on the size of the confining pressure

and the bond strength has little influence on the stress-strain curve of the contact bond model

but huge influence on the parallel bond model. It is concluded that the iterative calibration method can effectively calibrate macro-meso parameters and reduce the "test parameter" process.