On the AVISA model for clay – Recommendations for calibration and verification based on the back analysis of a piled raft.

This paper provides a manual for the thorough calibration of material parameters of the anisotropic visco ISA (AVISA) model and discusses some of the pitfalls that can arise when performing numerical analysis of geotechnical problems using this constitutive model. Considering element test simulations as well as finite element calculations, clear recommendations are extracted for the initialization of state variables based on comparative studies. Restrictions of parameter values to avoid numerical instabilities are revealed, and recommendations are provided. In addition, simulations of various laboratory tests on Frankfurt clay are analyzed and discussed. The model's performance is further validated by means of 3D finite element analysis of the piled raft of the Messeturm in Frankfurt, for which extensive measurement data are available. The simulations comprise both the construction phase and the subsequent long-term deformation due to creep. [ABSTRACT FROM AUTHOR]