2. Modeling A

2.1. Characteristics of modeling

Fig. 2.1 3D modeling.

Tableau 2.1 Caractéristiques du maillage.

Number of knots	20
Number of meshes	1 of the HEXA 20 type 6 of the QUAD 8 type

The symmetry boundary conditions are:

On the stitches DEVANT and DERRIERE : :math:`DX=0`. *On the stitches GAUCHE and DROITE : :math:`DY=0`. *On the mesh BAS *: \(DZ=0\).

During the isotropic compression phase, the same normal stress is imposed on the three meshes HAUT, DROITE and * DEVANT. During the triaxial compression phase, this normal stress remains imposed on DROITE and DEVANT. Simultaneously, vertical displacement is imposed increasing in compression on the HAUT mesh.

It should be noted that during these two charges, neither the capillary pressure nor the gas pressure varies. They remain equal to \(\mathrm{PRE1}={200}\) kPa and \(\mathrm{PRE2}={1}\) Pa respectively.

2.2. Tested sizes and results

The solutions are calculated at points NO8 to \(t=1\) and \(t=2\) each corresponding to the times at which the two loads are completed. They are given in terms of radial deformation \(\varepsilon_{xx}\) and net axial stress \(\sigma_{zz}''\) in v7.31.123-resultats_grandeurs.

The Fig. 2.2 shows the answers obtained.

Fig. 2.2 Changes in radial deformation \(\varepsilon_{xx}\) and net axial stress \(\sigma_{zz}''\) with axial deformation \(\varepsilon_{zz}\) during both isotropic and triaxial compression loads.