M2S and M1S

M2S is a two surfaces mixed isotropic-kinematic hardening plasticity model for natural soils obtained by hierarchically extending the Modified Cam-Clay model to include an early development of non-linearity, improved memory of stress history, anisotropy and the effects of structure and its degradation with plastic straining.

M2S reduces to M1S when only a single yield surface is considered. This latter model is implemented in Plaxis with a fully implicit stress-point algorithm ensuring numerically stable and first-accurate solutions at the Gaussian point level even in presence of stronly non-linear material response.
 

References:

Amorosi, A., Kavvadas, M. (1999), ‘A plasticity-based constitutive model for natural soils: a hierarchical approach’, In D. Kolymbas editor, Constitutive Modelling of Granular Materials, Springer 413-438.

Kavvadas, M., Amorosi, A. (2000), ‘A constitutive model for structured soils’; Géotechnique 50 (3), 263-274.

Amorosi, A., Boldini, D. (2003), ‘Single surface hardening plasticity model for soft clays: mathematical formulation and implicit numerical integration.’, Proc. International Workshop on Geotechnics of Soft Soils / Theory and Practice, Noordwijkerhout, 153-158.

Amorosi, A., Boldini, D., Elia, G., Germano, V. (2005), ‘A generalised backward Euler scheme for the integration of a mixed isotropic-kinematic hardening model for clays’, 8h Int. Conference on Computational plasticity COMPLAS2005, Barcelona, Part2, 926-929.
 

For more information and to obtain the model, please contact:

Dr. Daniela Boldini
University of Bologna
Dept. of Chemical, Mining and Environmental Engineering
via Risorgimento 2, 400136 Bologna (Italy)
tel: +39-051-2093390
fax: +39-051-2093392
e-mail: daniela.boldini@unibo.it
 

Prof. Angelo Amorosi
Technical University of Bari
Dept. of Civil and Environmental Engineering
Geotechnical Section
Via E. Orabona 4, 70125 Bari (Italy)
tel: +39 (0)80-5963693
fax: +39 (0)80-5963675
e-mail: a.amorosi@poliba.it
 

Please note: This model is available as a user-defined soil model. However, Plaxis does not accept any responsibility when using this DLL. Hence, the user needs to validate results obtained from this model by him/herself. Plaxis does not provide support on the use of this model.