The text presents a comparison of three different anisotropic constitutive models in a computer programme, which employs the finite element method. In this particular case Plaxis program package is used, which by default offers two models that take very different approaches to deal with the phenomenon of anisotropy. The first is Jointed rock model and the second is NGI-ADP model for analysis of soft clays in undrained conditions. As an alternative a new user defined model is introduced to Plaxis, which describes anisotropy with specially defined scalar parameter. In the first chapter a general description of anisotropy is given, followed by outline of some different theoretical approaches to modeling anisotropy. In second chapter the theoretical background of programme Plaxis is given. This chapter contains the main assumptions and mathematical relations on which finite element method is based, as considered by Plaxis.
In chapters three to five all three material models are separately introduced. For each model a detailed description with assumptions, main characteristics and parameters is given. This is followed by sixth chapter which contains the description of procedures for the development of user defined material models within Plaxis.
In the seventh chapter the direct comparison of three models is given backed up by numerical analysis and parametric study.
In the last chapter the concluding remarks and some recommendations for future scientific work are given.
|
