关键词: 密实砂土, 离散元模拟, 抗转模型, 宏?细观参数, 剪切带, 剪胀角

Abstract: Macro-meso parameter calibration of the contact model is the key to successful use of the discrete element method. Linear contact model and rolling resistance linear contact model in the discrete element contact model can be used to simulate the mechanical behavior of sand, and the rolling resistance linear contact model has advantages in simulating the dilantancy of dense sand. Discrete element simulation is carried out for triaxial test of dense sand by using the rolling resistance linear contact model, which verifies the reliability of the rolling resistance linear contact model. Furthermore, the correlations between the meso-parameters such as inter-particle friction coefficient, stiffness ratio and rolling resistance coefficient and the macro-parameters such as peak internal friction angle, residual internal friction angle and peak angle of dilantancy of sand are systematically analyzed. The influence of meso-parameters on shear band width and inclination of dense sand under deviatoric stress is revealed. An empirical formula of shear band inclination angle considering dilatancy angle is proposed. Quantitative relationship between macro and meso parameters of rolling resistance linear contact model is established through research, which providing basis for precisely simulating mechanical characteristics of dense sand by using rolling resistance linear contact model. The flow chart of calibration is given. A method for fast calibration of macroscopic parameters is proposed and verified by an example.

Key words: dense sand, DEM simulation, rolling resistance linear contact model, macro-meso parameters, shear band, dilation angle