Numerical Investigation on the Reference Crushing Stress of Granular Materials in Triaxial Compression Test

Particle crushing dominates the deformation behaviour of granular materials under significantly high compressive and shear stress. A proposed constitutive model has been verified to predict crushing behaviour of granular materials with different crushability and adopted one kind of reference crushing stress. It is noted that no positive dilatancy of granular material in triaxial test occurs once the confining pressure exceeds a certain stress level. That stress is defined as the reference crushing stress. This study presents a parametric study on the reference crushing stress in the constitutive model and examines its variation for different distributed ranges of grain size gradation and relative densities. Predicted results demonstrate that the peak stress ratio increases and contractive behaviour becomes less obvious with a larger reference crushing stress. Reference crushing stress increases with a wider grain size gradation and larger relative density for the same granular material. A linear relationship between the reference crushing stress and single particle strength has been obtained from the numerical and experimental results. The reference crushing stress can be recognized as one effective index to evaluate the strength of granular material in triaxial tests.