Influence of Particle Shape on the Mechanical Property of Granular Materials

Abstract

Granular materials exist extensively in nature and the particle shape has great influence on the mechanical property of granular materials. In order to study the influence of particle shape on the mechanical property of granular materials and establish the relationships between the micro-parameters of particle shape and macro-parameters of the mechanical property of granular materials, a 3D shape quantitative method based on two-dimensional analysis was proposed, by which the granular shape of same materials and three types of particles (sphere, elliptic cylinder and plate) was described. The direct shear tests were done under the same relative density and different normal loads, from which the rules of shear stress and dilatation with particle shape were found. The stress-dilatancy model was introduced and parameter \( \upmu \) representing friction angle of particles was revised to consider the influence of particle shape. The results show that the more irregular the particle shape, the higher the peak shear stress and peak vertical displacement. These macro-mechanical properties were resulted from the different particle boundaries and relative movements. At last, the relationship between the parameter \( \upmu \) of stress-dilatancy model and particle shape could be calculated. The parameter \( \upmu \) becomes larger as the particle shape becomes more irregular but its increasing rate becomes slower and slower.