A Constitutive Model for Coarse Granular Material Incorporating Both Strain Work-softening and Dilatancy

Based on the traditional constitutive model for cohesionless soil,an elasto-plastic model for coarse granular material is proposed,which can describe both strain work-softening and dilatancy reasonably.The two yield surfaces model can reflect shear deformation and compression deformation respectively,making up for the deficiency of single yield surface model,and the relativity between phase transformation stress ratio and initial effective pressure is considered when describing the dilatancy of coarse aggregates.A strain work-softening equation including the stress ratios at steady state and peak state is developed,which can express the characteristic of strain work-softening preferably.The numerical simulation agrees well with the data of large-scale triaxial compression test,which proves the model to be of the priority in describing the dilatancy and strain work-softening under low and relatively high confining pressure.