Stress–dilatancy relationship for fiber-reinforced sand and its modeling

The stress-dilatancy relationship could be employed as the foundation to develop a constitutive model for polypropylene fiber-reinforced (PFR) soils. In this study, a number of triaxial compression tests were carried out to investigate the effect of uniform distributed fiber reinforcements on the stress dilatancy relationship of Nanjing sand. A new parameter representing the increase in the effective confining stress sigma(FR) was introduced to describe the stress-dilatancy of PFR sand, and a new stress-dilatancy relationship was proposed for PFR sand based on Rowe's stress-dilatancy equation for granular materials. Moreover, the stress-dilatancy relationships in the conventional triaxial compression, extension and plane stain conditions were discussed in this paper. The stress-dilatancy relationship is validated against a series of triaxial tests on Nanjing sand and Hostun RF sand mixed with discrete polypropylene fibers. It is shown that the predicted results are in a good agreement with the experimental results.