Abstract:

A well established constitutive model not only confidently simulates the stress-strain characteristics of geomaterials, but also properly reflects the lateral deformation of geomaterials; specifically, the generalized Poisson’s ratio shall be reliably figured out by using the constitutive model. Based on elliptic-parabolic yield surfaces model, a generalized Poisson’s ratio was derived to reflect the characteristics of geomaterials’ lateral deformation characteristics. Effects of main model parameters on the magnitude of Poisson’s ratio were analyzed. Parameters associated with dilatancy were found clearly affecting the generalized Poisson’s ratio. Based on the results of consolidated-drained triaxial shear tests of sand-expanded polystyrene (EPS) lightweight fills, verification was conducted with respect to the elliptic-parabolic yield surfaces model and the generalized Poisson’s ratio. It is shown that the model largely simulated the stress-strain characteristics of fills, so did the generalized Poisson’s ratio on describing fills’ deformation behavior, i. e. dilatancy, contraction and lateral deformation.

Key words: elliptic-parabolic yield surfaces model, generalized Poisson’s ratio, lightweight fills, lateral deformation, stress-strain curves, main diagonal elements