Implementation, Validation, and Application of PM4Sand Model in PLAXIS

This paper presents the implementation, validation, and application of the PM4Sand model (version 3) formulated by Boulanger and Ziotopoulou (2015) in the PLAXIS finite element code. The model can be used for modelling geotechnical earthquake engineering applications, especially in the case liquefaction is likely to occur. The PM4Sand model represents an improvement of the elasto-plastic, stress ratio controlled, bounding surface plasticity model for sands formulated by Dafalias and Manzari (2004). The two-dimensional version has been implemented in PLAXIS and compared to the original implementation by Boulanger and Ziotopoulou (2015). The original implementation has been used in explicit finite difference simulations which can be sensitive to the size of the returned stress increment, based on the chosen time step size and loading rate. Therefore, the user needs to evaluate the sensitivity of the solution with respect to the chosen time step sizes. On the contrary, in the finite element method used here, the default time step together with the sub-stepping used at the constitutive model level provide a robust solution independent of the size of the returned stress increment.