MODELLING STRAIN-SOFTENING BEHAVIOUR OF CLAYEY SOILS

ABSTRACT: A method for modelling strain-softening phenomena has been applied to simulate the mechanical behaviour of undisturbed Ariake clay and lime-stabilized Ariake clay samples under undrained conditions. The method is based on the Modified Cam Clay (MCC) model, and during the softening process the effective stress path is forced to follow the critical state line (CSL). The method simulates well both the shear strain versus deviatoric stress curve and the effective stress path of undisturbed Ariake clay samples. For the lime-stabilized Ariake clay samples, the simulation gave a fair prediction of the test data for the case with a relatively high initial confining stress (p′o = 382 and 510 kPa), but a relatively poor simulation for the case of lower initial confining stress (p′o = 127 kPa). To model accurately the mechanical behaviour of lime-stabilized Ariake clay, the adoption of a high initial stiffness under lower confining stress has to be considered. It is suggested that the method adopted in this study can be used to analyze with reasonable accuracy geotechnical problems involving strain-softening behaviour