FAIF3

3D fault interface

Type: 227

The element consists of 4 or 8 nodes (DoF 1, 2, 3, 4, 5, and 6) relating to one side of the fault (= the structure), and 4 or 8 additional nodes to discretize the flow of water, gas, or temperature inside the fault (DoF 4, 5, and 6). It also relates to a predefined foundation.
The normal (red side in DESFIN) must go out of the structure.

The foundation, defined by a series of triangular or quadrangular sides, is defined in the “FOUND” section of the *.lag file. If the foundation is defined by a series of sides, the normal is given by the product of vectors $\vec{12}$ and $\vec{13}$ built on the nodes of the foundation $\vec{n}=\vec{12} \wedge\vec{13}$ of each side. This normal must be directed inwards the foundation.

This element is dedicated to soil mechanics and in particular to structure-structure contact (fault). It includes pressure, friction, flows axial to the fault (water, gas, thermal), and two (x3) flows (water, gas, thermal) transversal to the fault (along the thickness).

The element can work in coupled mechanical-water-air-temperature analysis, with 6 DoF.

This element can use mechanical law INTME3 or a classic law and flow law INTFL3.

Warning: When using renumbering of the DoFs, only directional renumbering works.

Implemented by: J.P. Radu, 2007

Prepro: FAIF3A.F
Lagamine: FAIF3B.F

Stresses (24):

• Pressure
• Tangent stress in direction 1
• Tangent stress in direction 2
• 0
• Longitudinal water flow $f_{w,x,loc}$ in the plane of the element,
• Longitudinal water flow $f_{w,y,loc}$ in the plane of the element,
• Stored water flow,
• “FI” (between Foundation and Inside) transversal water flow
• “IS” (between Inside and Structure) transversal water flow
• Longitudinal gas flow $f_{g,x,loc}$ in the plane of the element,
• Longitudinal gas flow $f_{g,y,loc}$ in the plane of the element,
• Stored gas flow,
• “FI” (between Foundation and Inside) transversal gas flow
• “IS” (between Inside and Structure) transversal gas flow
• Longitudinal thermal flow $f_{t,x,loc}$ in the plane of the element,
• Longitudinal thermal flow $f_{t,y,loc}$ in the plane of the element,
• Stored thermal flow,
• “FI” (between Foundation and Inside) transversal thermal flow
• “IS” (between Inside and Structure) transversal thermal flow
• Longitudinal vapor flow $f_{v,x,loc}$ in the plane of the element,
• Longitudinal vapor flow $f_{v,y,loc}$ in the plane of the element,
• Stored vapor flow,
• “FI” (between Foundation and Inside) transversal vapor flow
• “IS” (between Inside and Structure) transversal vapor flow

Internal variables (4+2+25 = 31):
The first values are the ones relating to the law
For INTME2/INTME3, this will be:

• plasticity indicator,
• dissipation,
• fault closing $V$,
• fault opening $D$

The 2 next values correspond to the contact geometry. They are:

• The segment number of the foundation in contact
• The interpenetration distance

The last values are those relating to the flow law; for INTFL3, they are:

• The relative permeability to water
• The relative permeability to gas
• The porosity
• The saturation to water
• The suction
• The specific mass of water
• The specific mass of gas
• Peclet number
• The water content
• The specific mass of vapor
• The vapor pressure
• The relative humidity
• The mass of liquid water per unit volume
• The mass of dry air per unit volume of soil
• The mass of vapor per unit volume of soil
• The intrinsic longitudinal permeability
• The gas saturation
• The partial pressure of hydrogen (not used)
• The water pressure inside the fault
• The gas pressure inside the fault
• The temperature inside the fault
• The transversal transmissivity of water
• The transversal transmissivity of gas
• The thermal transversal transmissivity
• The thermal conductivity