CONSTITUTIVE MODELING OF CEMENTED SAND

A true triaxial testing apparatus was developed and used by the authors to test uncemented and cemented sands under different stress paths. This test data are used in this paper to examine the applicability of two constitutive models which have been developed by other researchers. The first model, due to Lade (known as Lade's model), is an elasto-plastic model with single yield surface and plastic potential. The second model, due to Valanis and co-workers (known as endochronic model), is reminiscent to (Bolzmann) nonlinear viscoelasticity, where ordinary time is replaced by a weighted arc length of the plastic strain in plastic strain space. The procedures for determining 13 and 12 material parameters for the respective models are explained. Predictions based on the two models are obtained and compared with experimental data for simple loading histories composed of initial hydrostatic prestress and subsequent proportional loading.