Comparison of a microscopic model and a macroscopic model predictions on the stress-strain behavior of a soil

The stress-strain behavior of a soil under drained triaxial conditions was simulated using the Microscopic constitutive model TRUBAL. The model parameters for the Macroscopic constitutive (Bounding Surface) model was estimated by matching simulated stress-strain behaviors from TRUBAL and predicted stress-strain behavior from Bounding Surface Model. Using the same model parameters for both TRUBAL and Bounding Surface Model, the following stress-paths were predicted and compared: a) the plane-strain triaxial test, and b) the constant hydrostatic or constant-p triaxial test. It appears that there is a reasonable agreement between the predictions from the two approaches. Then an attempt was made to better understand the internal variables associated with the Macroscopic model.