A numerical implementation of the SANISAND-MSf constitutive model: validation and model performance

The SANISAND family of constitutive models has undergone continuous refinement over the years, with successive versions aimed at improving the simulation of the undrained cyclic behaviour of sandy soils, with the primary objective of accurately capturing their response in liquefaction-prone environments. In a recent development, the concept of a Semi-fluidised (Sf) state has been integrated within a Memory Surface (MS) framework, thus leading to the SANISAND-MSf model and enhancing its capability to predict large deformations in the post-liquefaction regime. This paper presents the results of the implementation of the SANISAND-MSf model and demonstrates its potential to simulate liquefaction phenomena. The implementation is first validated through comparison with existing numerical simulations of stress-controlled undrained cyclic triaxial tests on different Karlsruhe sand samples. Subsequently, the implementation performance is further assessed against experimental results from both stress- and strain-controlled undrained cyclic triaxial tests reported in the literature for the same sand. Finally, the influence of a key parameter characterising the numerical implementation is investigated to provide useful guidance for the users of the model.