The Creep-SCLAY1S model is capable of simulating the anisotropic and rate-dependent behaviour of soft soils. The mathematical formulation also includes the possibility to model bonding and destructuration. Many constitutive models have been proposed in literature to describe the behaviour of structured natural clays. Most of the rate-dependent models were developed based on the Perzyna' (Perzyna (1963) and Perzyna (1966)) overstress theory (e.g. Hinchberger & Rowe (2005) and Zhou, Yin, Zhu & Cheng (2005)), with the disadvantage of a difficult parameter calibration process (Karstunen & Yin (2010)). Another approach consists in using empirical formulations, as for example the Soft Soil Creep model available in the PLAXIS standard library. The Creep-SCLAY1S can be considered a special kind of extended overstress model derived from an empirical equation (Sivasithamparam, Karstunen & Bonnier (2015)).

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The PM4Sand model successfully simulates the material behaviour of sands in dynamic loading, including the pore pressure generation, liquefaction and post-liquefaction phenomena. It is a very attractive model for the industry due to a small number of parameters to be calibrated. They are mostly related to the usually available data in the design practice (e.g. DR, SPT, CPT, Vs values). This report summarises the implementation of the PM4Sand model version 3.1 (Boulanger & Ziotopoulou, 2017) in the PLAXIS finite element code. The model is defined in the basic framework of the stress-ratio controlled, critical state compatible, bounding surface plasticity model for sand by Dafalias & Manzari (2004). Many modifications were added to the Dafalias & Manzari (2004) model in order to more accurately simulate stress-strain responses that are important to geotechnical earthquake engineering practice. The developments are described in the manuals (version 1: (Boulanger, 2010); version 2: (Boulanger & Ziotopoulou, 2012); version 3: (Boulanger & Ziotopoulou, 2015); version 3.1: (Boulanger & Ziotopoulou, 2017)).@en

This book presents the proceedings of the 21st European Young Geotechnical Engineers Conference (EYGEC), held in the Netherlands in September 2011. Six sections cover the topics of: underground construction; pile foundation and ground improvement; soil dynamics; dams, erosion and piping; deformation and soil properties and geothermics. The papers included here present the new and refreshing perspective of young engineers exploring the field of geotechnics.@en