Reference problem
=====================


Geometry of the problem
---------------------

It is a column with height :math:`\mathit{LZ}=5m`, length :math:`\mathit{LX}=1m`, and width :math:`\mathit{LY}=1m`. In :math:`Z=\frac{\mathit{LZ}}{2}`, this column has an interface-type discontinuity. The column is thus entirely crossed by the discontinuity.

The geometry of the column is shown in the figure.


.. image:: images/10000000000001A40000019F01972182FF094FCE.jpg
    :width: 3.7681in
    :height: 3.9571in


.. _RefImage_10000000000001A40000019F01972182FF094FCE.jpg:

**Figure** 1.1-a **: Problem geometry**


Material properties
--------------------

The parameters given in the Table correspond to the parameters used for modeling in the hydromechanical coupled case. The coupling law used is' LIQU_SATU '. The parameters specific to this coupling law are given but have no influence on the solution (because we chose to take a uniformly zero pore pressure throughout the domain). Only the elastic parameters have an influence on the solution of the pseudo-coupled problem.


.. csv-table::

    "Liquid (water)", "Viscosity :math:`{\mu }_{w}(\mathit{en}\mathit{Pa.s})`
    Compressibility module :math:`\frac{1}{{K}_{w}}(\mathit{en}{\mathit{Pa}}^{\text{-1}})`
    Liquid density :math:`{\rho }_{w}(\mathit{en}\mathit{kg}\mathrm{/}{m}^{3})` "," :math:`{10}^{\text{-3}}`
    :math:`{5.10}^{\text{-10}}`
    :math:`1`"
    "Elastic parameters", "Young's modulus :math:`E(\mathit{en}\mathit{MPa})`
    Poisson's ratio :math:`\nu`
    Thermal expansion coefficient :math:`\alpha (\mathit{en}{K}^{\text{-1}})` "," :math:`5800`
    :math:`0`
    :math:`0`"
    "Coupling parameters", "Biot coefficient :math:`b`
    Initial homogenized density :math:`{r}_{0}(\mathit{en}\mathit{kg}\mathrm{/}{m}^{3})`
    Intrinsic permeability :math:`{K}^{\text{int}}(\mathit{en}{m}^{2}/s)` "," :math:`1`
    :math:`\mathrm{2,5}`
    :math:`{\mathrm{1,01937}}^{\text{-19}}`"


**Table** 1.2-1 **: Material Properties**

On the other hand, the forces related to gravity (in the equation for the conservation of momentum) are neglected. The reference pore pressure is taken to be zero :math:`{p}_{1}^{\text{ref}}=0\mathit{MPa}` and the porosity of the material is :math:`\varphi =\mathrm{0,15}`.

We take :math:`\nu =0` in order to have a one-dimensional problem in the :math:`y` direction.


Boundary conditions
----------------------

The boundary conditions that can be applied to the domain are of two types:


* Dirichlet-type conditions,


* Neuman-type conditions.

Dirichlet's conditions are:


* on [ABCD] and [EFGH] the movements are blocked in all directions (:math:`{u}_{\text{x}}=0`, :math:`{u}_{\text{y}}=0` and :math:`{u}_{\text{z}}=0`),


* throughout the domain the pore pressure is zero :math:`{p}_{1}=0`, as is the enriched degree of freedom associated with this pore pressure :math:`{\mathit{Hp}}_{1}=0`.

Neuman's conditions are:


* on [ABCD] and [EFGH] the mass fluxes of water are zero :math:`M\mathrm{.}n=0`,


* On each of the lips of the interface, a uniform distributed pressure is imposed :math:`p=10\mathit{MPa}` by means of AFFE_CHAR_MECA and the keyword FISSURE of PRES_REP.

Gravity:


* over the entire domain, the gravity volume load of intensity :math:`g=\mathrm{9,81}m\mathrm{.}{s}^{-2}` is applied via AFFE_CHAR_MECA with the keyword CHAR_MECA_PESA_R.