Mixed Experimental and Numerical Approach to Evaluation of Material Parameters of Clayey Soils

Abstract

The present contribution reports on a mixed numerical experimental study of the time dependent processes in saturated soils with reference to isotropic consolidation. Owing to its relative simplicity, isotropic consolidation is often viewed as a basic tool for inferring the material parameters of various constitutive models. Within this modeling framework, the paper advocates the use of critical state models for an accurate description of the time dependent deformation of clayey soils. Material models, in which the critical state model applies only to the subcritical region, have been also addressed. Examples include models where the supercritical region is cut off, e.g., by a Mohr–Coulomb surface. Starting with the modified Cam clay model, as a classical representative, the paper revisits a simple isotropic consolidation test. It is suggested that such a conventional laboratory experiment, when combined with a suitable optimization procedure, is sufficient in deriving the desired material parameters, including the initial void ratio, deformation dependent variation of the coefficient of permeability and the preconsolidation pressure representing here an important measure of the structural strength of soils. Several numerical and experimental results are presented to support the theoretical grounds.