NorSand: An elasto-plastic model for soil behaviour with static liquefaction

With the release of PLAXIS 2D/3D CONNECT Edition V21, a new User Defined Soil Model for (static) liquefaction analysis is introduced, the NorSand model (Jeffries, Been, 2016).

NorSand (NS) is a critical state soil model implemented within the wider theory of work-hardening plasticity. It is capable to account for the effect of void ratio on soil behavior by using the state parameter as a key controlling variable, that is the difference between the void ratio and its critical state value. The "Sand" in the model is only to denote the ability of NS to accurately represent the dilation of dense soils. Soil properties in NS are limited in number, mostly standard in the geotechnical community, and can be easily obtained via conventional laboratory tests. Usually, a few triaxial compression tests will suffice to calibrate the model. Although the most prominent use of this model has been to simulate static liquefaction of loose silts, it can be used to capture soil behavior over a wide range of densities and confining stresses.

Figure: Undrained mechanical response predicted by NorSand for loose and dense conditions