Investigation of engineering behavior of soft soil located Cukurova region by constitutive soil models

Advanced geotechnical design on soft clays has often been based on finite-element analyses using isotropic elasto-plastic modified cam clay model. Natural clays, however, exhibit anisotropy and the effect of bonding between particles. These features are very important in modelling the stress strain behaviour of soft clays. Therefore, there is a need for a constitutive model that can adequately account for fundamental features of soil, such as anisotropy, destructuration, and creep in a relatively simple manner. Two recently proposed constitutive models are namely S-CLAY1 which accounts for initial and plastic strain induced anisotropy, and its extension, called S-CLAY1S which accounts, additionally, for interparticle bonding and degradation of bonds. However, the application of these models to practical geotechnical design is not common, because the determination of the model input parameters is often cumbersome, and it may even require nonstandard laboratory tests. In this study, S-CLAY1 and S-CLAY1S models are applied to represent the soft clay in two different locations in Cukurova Region. The model parameters were determined from the results of standard laboratory tests by using well-defined methodologies. Furthermore, the models have been successfully validated against experimental data simulating laboratory tests. For comparison, the tests is also analysed with the isotropic modified cam clay model. Finally, the construction and consolidation of a benchmark embankment constructed on soft soil deposits at Cukurova region was analysed with the finite-element method using three different constitutive models (S-CLAY1, S-CLAY1S and MCC) assuming soil parameters corresponding to natural Cukurova clay. The simulations demonstrate that for this type of problem it is important to account for the anisotropy and destructuration in geotechnical design.