Strength and Dilatancy Behaviors of Dense Modeled Rockfill Material in General Stress Space

Abstract

The strength and dilatancy behaviors of modeled dense rockfill material were systematically investigated through a series of true triaxial compression tests at different minor principal stress and intermediate principal stress ratios. It was found that the intermediate principal stress ratio had great influence on the critical-state friction angle, peak-state friction angle, and maximum dilatancy of the modeled rockfill material. Both the critical-state and peak-state friction angles at a given confining pressure first increased and then decreased with an increase in the intermediate principal stress ratio. An increase in the minor principal stress led to a decrease in both the critical-state and peak-state friction angles at a given intermediate principal stress ratio. The maximum dilatancy decreased with an increase in the minor principal stress or the intermediate principal stress ratio. It was also found that the intermediate principal stress ratio significantly affected the relationship between the peak-state friction angle and maximum dilatancy. An adapted stress–dilatancy equation (incorporating a state index and a function of the intermediate principal stress ratio) could be used to capture the stress–dilatancy behaviors of modeled rockfill materials at different intermediate principal stress ratios.