Numerical Modeling: An Efficient Tool for Analyzing the Behavior of Constructions - Multiscale Geomechanics: From Soil to Engineering Projects - page 284

Figure 9.13. Relation given by Khalkhali and Khabbaz [KHA 98] for Skempton's χ parameter

9.4.3.1. Parameter b

This parameter controls the form of the yield surface and can vary between 0 for a
Mohr-Coulomb and 1 for a Cam Clay type surface. A value equal to 1 can be considered
acceptable for clays. We may choose b between 0.1 and 0.2 for sands.

9.4.3.2. Parameters related to plastic stiffness a 1 and a 2

These parameters which control the evolution of the yield surface play an important
role.

9.4.3.2.1. Clays

Numerical simulations to calibrate the G − γ and D − γ given by Vucetic and
Dobry [VUC 91] for clays have made it possible to establish a correlation between
theses parameters and the factor

G max

σ 0 OCR for the range of OCR studied [LOP 03a]. As
we see in Figure 9.14, the range of their variation depends on the plasticity index I p .

9.4.3.2.2. Sands