I am using clay hypoplastic umat code and trying to verify the code with the simulation on the paper of Prof. Masin. I found in the paper (Masin, 2005, A hypoplastic constitutive model for clays) there is no details of boundary conditions of the simulation but stress path. As shown in the picture, the p and q are not straight line and also be normalized by pe^asterisk which varies with void ratio. The paper describes the three experiments which are also simulated by clay hypoplasticity as follows:
PhM19: shear test with constant mean pressure on K0 overconsolidated specimen.
PhM21: undrained compression test on a nearly normally compressed specimen.
PhM17: constant p0 extension test on a K0 overconsolidated specimen
I am a little bit confused about these description — for PhM19, what is constant mean pressure? Is that mean we need to change both horizontal pressure and vertical pressure at the same time in the triaxial shear test simulation to make the mean pressure constant? And which parameter will be changed by switching overconsolidated specimen to normally compressed specimen? If the OCR of normally compressed specimen is 1, what is the OCR for K0 overconsolidated specimen?
I am not sure if this is a common questions or it is because my shortage of background. I appreciate your response!