No abstract

The objective of this study is to derive a time dependent effective based constitutive law on the basis of framework of the Modified Cam-Clay model. This model takes into account the anisotropic characteristics and creep behavior, based on the theory of viscoplasticity. The model sets the initial yield surface symmetric to the K 0 line for modeling the initial K 0 condition. A method is then developed to compute the gyration and expansion of the loading surface to simulate the anisotropic behavior due to the principal stress gyration after shear. The creep or time dependent behavior is considered in the model by adopting Kutter and Sathialingam's model, which was derived from Taylor's secondary consolidation theory and Bjerrum's delayed compression model. Compared with the Modified Cam-Clay model, the model requires five additional parameters to describe the soil behavior. All of the additional parameters can be obtained through conventional soil tests or parametric studies. The model is evaluated through a series of simulation of undrained shear tests and undrained creep tests.

SUMMARYThe objective of this study is to derive an effective stress-based constitutive law capable of predicting rate-dependent stress-strain, stress path and undrained shear strength and creep behavior. The flow rule used in the MIT-E3 model and viscoplasticity theory is employed in the derivation. The model adopts the yield surface capable of representing the yield behavior of the Taipei silty clay and assumes that it is initially symmetric about the K 0 -line. A method is then developed to compute the gyration and expansion of the loading surface to simulate the anisotropic behavior due to the principal stress rotation after shear. There are 11 parameters required for the model to describe the soil behavior and six of them are exactly the same as those used in the Modified Cam-clay model. The five additional parameters can be obtained by parametric studies or conventional soil tests, such as consolidation tests, triaxial compression and extension tests. Finally, verification of the model for the anisotropic behavior, creep behavior and the rate-dependent undrained stress-strain and shear strength of the Taipei silty clay is conducted.

No abstract

No abstract