There is a clear procedure to determine the model parameters. However, it is (still) a two-dimensional model, just like the original. PM4Sand can be regarded as an advanced cyclic loading and liquefaction model. The PLAXIS implementation (Vilhar et al., 2018) gives very similar results as the original model, but the PLAXIS2D model is probably more efficient since it is implemented in an implicit finite element environment. PM4Sand Constitutive ModelĪ few years after the first model, the PM4Sand model was implemented in PLAXIS2D, following the original implementation (Version 3) by Boulanger & Ziotopoulou (2015). In addition to an extensive validation by PLAXIS and various universities, NTUA in Athens, Greece, published a procedure for the determination and calibration of model parameters (Anthi & Gerolymos, 2019). In combination with undrained behavior, it builds-up pore pressures, which may lead to liquefaction after a certain number of cycles (depending on its parameter values).
UBC3D-PLM has remarkable similarities with the Hardening Soil model, with the extra feature that it accumulates plastic strains in cyclic loading. This is a 3D implementation of the two-dimensional UBCSand model, as originally developed by Beatty & Byrne (1998) at the University of British Columbia (UBC). The first model for cyclic loading and liquefaction that PLAXIS implemented was the UBC3D-PLAXIS Liquefaction Model. Only the Hardening Soil model with small-strain stiffness includes the first feature and may be used in dynamic calculations for non-liquefiable soils. Decrease of stiffness and increase of (shear) strain when reaching liquefactionĭespite the advantages of advanced constitutive models, such as the Hardening Soil model and the Soft Soil model, these models do not capture the features as mentioned above.Build-up of pore pressures in undrained cyclic loading.Accumulation of (plastic) strains in cyclic loading.Degradation of stiffness and strength in cyclic loading.Strain-dependent stiffness (modulus reduction) and regain of small-strain stiffness upon load reversal strain-dependent hysteretic damping.
These are mostly related with the effects of cyclic loading, such as: Read more about PLAXIS 2D/3D Features of Soil Behavior in Dynamic and Cyclic Loadingĭynamic calculations require other features of soil behavior to be included in a constitutive model than static calculations. Since dynamic calculation phases are generally preceded by static phases, you may need to ‘switch’ the material datasets of the soil layers at the start of your dynamic calculation. It is important to realize that advanced models for static loading are not necessarily good for dynamic loading (and vice versa).
Viscous, free-field and compliant base boundaries that represent the far field and prevent spurious wave reflections at the model boundaries.Constitutive models for cyclic loading and liquefaction.Calculation types ‘Dynamic’ and ‘Dynamic with consolidation’.PLAXIS 2D/3D Ultimate includes the essential facilities for the numerical modelling of earthquakes and liquefaction, such as: Numerical Modeling of Earthquakes and Liquefaction Important backgrounds on geotechnical earthquake engineering and liquefaction can be found in the books by Kramer (1996) and Idriss & Boulanger (2008). It requires understanding of the terminology and methods that are necessary to safely design structures against earthquakes as well as understanding of the features of soil behavior under dynamic and cyclic loading, including liquefaction. Geotechnical Earthquake Engineering is a special discipline in the geoengineering profession. Brinkgreve, and first presented by Virtuosity.