Abstract:

Many biaxial tests of sands are simulated using PFC2D to study the formation and the development of the shear band. The relationship of stress and strain inside or outside the shear band is studied. Focus is extended to some variables such as the void ratio, the average coordination number and the pure rotation ratio inside and outside the shear band. The results show that the formation of the shear band is characterized with both strain localization and the localization of the averaged pure rotation ratio (APR). The shear band starts right at the point where the volume strain changes from shrinkage to expansion. The development of these variables are significantly different within or outside of the shear band. Particularly, the stress-strain softening relationship was observed near or within the shear band, while the hysteretic phenomenon takes place outside the shear band. In addition,  both the volumetric and deviatoric strains are larger inside than outside the shear band, with the soil being looser in the shear band.

Key words: distinct element method, shear band, sand, biaxial tests, strain-softening