Abstract
Elasto-plastic constitutive models for the undrained strain softening behavior of normally consolidated clays and mud rocks are proposed by using the non associated flow rule. Parametric studies are performed on three proposed yield functions to examine the applicability and limitation of the models. The simulated strain softening behavior is compared with the undrained triaxial compression test results for alluvial clay and diatomaceous mud rock. It is concluded that one of the proposed models is appropriate for the simulation of undrained stress strain relations taking account of the strain softening behavior.
