The impact of the fine-grained parameters of the anti-rotation model on the macroscopic mechanical properties of Fujian standard sand

Abstract

Based on PFC3D software, the mechanical response of model meso parameters to macro parameters of the Fujian sand triaxial test was analyzed. Combined with the results of indoor tests, the range of model parameters was determined. The simulation was conducted under the confining pressures of 100kpa, 300kpa and 500kpa respectively. After the macro parameters were obtained, the influence degree of each micro parameter on the macro parameters was analyzed through orthogonal test design to conduct sensitivity analysis on the contact modulus, stiffness ratio, friction coefficient, and anti-rotation coefficient of the sample. The results show that the elastic modulus is positively correlated with the contact modulus, friction coefficient, and anti-rotation coefficient, and negatively correlated with the stiffness ratio. The peak friction angle is negatively correlated with the contact modulus and stiffness ratio and positively correlated with the friction coefficient and anti-rotation coefficient. With the increase of the contact modulus and friction coefficient, the strain softening degree of the sample will increase, and the stiffness ratio and anti-rotation coefficient have no obvious effect on the strain softening degree. The contact modulus has little influence on the stable value of the mechanical coordination number of the sample. In contrast, the friction coefficient, stiffness ratio, and anti-rotation coefficient have greatly influenced the stable value of the mechanical coordination number. Compared with the orthogonal test design, the contact modulus has the greatest impact on the elastic modulus, and the stiffness ratio has the least impact on the elastic modulus. The friction coefficient has the greatest effect on the peak friction angle, and the stiffness ratio has the least effect on the peak friction angle. Based on the orthogonal experimental design results, a set of parameters is obtained. Finally, the PFC calibration results of Fujian sand are obtained by comparing the experimental results obtained from the predicted microscopic parameters with the laboratory tests, which provides a reference for future discrete element simulation laboratory tests.