A plasticity model for silt

Based on the theory of plasticity and the Cam Clay concept, a plasticity model is developed for accurately describing the constitutive behaviour of silty soils. While the model remains so simple that all the parameters may be obtained even from an undrained triaxial test, it takes into account contractancy, dilatancy, nonassociativity, volumetric and deviatoric hardening in plastic deformation. In particular, an analytical solution in undrained triaxial case has been derived, leading to a relation among the different parameters. Comparison of predictions and experimental data shows that the model can satisfactorily simulate the stress-strain-porepressure (volume) characteristics of silt in the undrained case as well as in the drained case.