ROLE OF RELATIVE DENSITY IN A BOUNDING SURFACE PLASTICITY MODEL FOR SAND.

A constitutive model for granular soil based upon the concept of bounding surface plasticity has recently been developed. In its present form, the model has the capacity of predicting drained and undrained behavior of sand in multiaxial stress space under both monotonic and cyclic loadings including rotational shear loading or principal stress rotation. The present model assumes that the failure surface and bounding surface of a given granular soil is uniquely defined for all values of relative densities. Instead, density-dependent model parameters are introduced to accommodate the response variations of a sand with different initial relative densities.