mpoint fluid command

Syntax

mpoint fluid keyword ... <range>

Primary keywords:

list    property    pore-pressure-generation

Set parameters for a groundwater analysis. Currently only undrained analysis is supported (change in pore pressure with mechanical changes). There are currently no fluid flow calculations performed.

list

information

Output current configuration settings and status information for the fluid model (this is the default if no keyword is given).

property <keyword> <range>

Output the values of the specified fluid property in all material points in the range. Enter no keyword to see a list of all possible fluid properties.

property keyword ... <range>

Assign fluid properties for all material points in the range. Any number of name-value pairs may be assigned. The type of the value given must match the type expected by the property s.

biot-coefficient f

Set the biot coefficient (grain compressibility), \(\alpha\). The default is 1.0. Note that if the biot-coefficient is set to something other than 1.0 then a biot-modulus must be specified and a fluid-modulus cannot be specified. This value is unitless.

biot-modulus f

Sets the Biot modulus. If the biot-coefficient is 1, this is related to the fluid-modulus by \(M = K_w/n\) where \(M\) is the Biot modulus, \(K_w\) is the fluid modulus, and \(n\) is the porosity. The default value is 0. In SI this value has units \([Pa]\).

fluid-density f

Specifies the fluid density for this mpoint. The default value is 0. In SI this value has units \([Kg/m^3]\). Note that the specified fluid density is only used to compute pore pressures with the mpoint pore-pressure command. This does not change the density of the volume represented by the material point. It is up to the user to specify different wet densities and dry densities above and below the water table.

fluid-modulus f

Specify the fluid modulus in material points. If the biot-coefficient is 1, this is related to the fluid-modulus by \(M = K_w/n\) where \(M\) is the Biot modulus, \(K_w\) is the fluid modulus, and \(n\) is the porosity. The default value is 0. In SI this value has units \([Pa]\).

fluid-tension f

MPoint fluid tension limit (f = -1e15 by default). This is the minimal (most tensile) pore pressure that can occur. Entry should be negative or zero.

porosity f

Specifies the porosity of the material points, \(n\). The default value is 0.5. This value is unitless.

pore-pressure-generation b

Specifies whether the material point will generate pore-pressure changes due to volumetric strain - or two way fluid coupling. By default this value is off.