Datum Dependent Properties
In the Material Properties dialog, the Datum Dependency tab allows you to define material properties that vary linearly with depth from a user-defined datum elevation, or linearly with radial distance from a user-defined center. The following properties can be specified as Datum Dependent:
- Cohesion and Friction Angle (only if Failure Criterion = Mohr-Coulomb and Material Type = Plastic).
To define Datum Dependent properties for a material:
- In the Material Properties dialog, select the Datum Dependency tab.
- Select the Datum Dependent checkbox.
- You will see the Datum Dependent Properties table, in which you can define the datum dependent properties as described below.
Cohesion
Cohesion can only be defined as a Datum Dependent property for materials with Failure Criterion = Mohr-Coulomb and Material Type = Plastic.
To define Cohesion as a Datum Dependent property, select the Cohesion checkbox in the Datum Dependent Properties table, and enter the following parameters.
DATUM TYPE
If the Datum Type = Depth you can define properties which vary linearly with depth from a user-defined datum elevation.
DATUM
The datum elevation (z-coordinate) when the Datum Type = Depth.
PEAK COHESION DATUM
The value of Cohesion (peak) at the Datum elevation (Datum Type = Depth). NOTE: the default value is taken from the Material Properties dialog.
PEAK CHANGE
The rate of change of Cohesion (peak) with (vertical) distance from the Datum (Datum Type = Depth). You can enter a positive or negative value to indicate increasing or decreasing rate of change with distance.
PEAK CUTOFF / CUTOFF VALUE
If you wish to specify a maximum (or minimum) value of Cohesion, select the Peak Cutoff checkbox and enter a Peak Cutoff Value. NOTE: if the rate of Change is positive, then the Cutoff Value represents the maximum peak cohesion. If the rate of Change is negative, then the Cutoff Value represents the minimum peak cohesion.
RESIDUAL COHESION AT DATUM
The value of Cohesion (residual) at the Datum elevation (Datum Type = Depth). NOTE: the default value is taken from the Material Properties dialog.
RESIDUAL CHANGE
The rate of change of Residual Cohesion with distance from the datum (elevation).
RESIDUAL CUTOFF / CUTOFF VALUE
You can specify a cutoff value for the Residual Cohesion, see above for details.
Friction Angle
Friction Angle can only be defined as a Datum Dependent property for materials with Failure Criterion = Mohr-Coulomb and Material Type = Plastic.
To define Friction Angle as a Datum Dependent property, select the Friction Angle checkbox in the Datum Dependent Properties dialog, and enter the Datum Dependent Friction Angle variables.
The definitions of the Datum Dependent variables for Friction Angle are the same as the definitions for Cohesion - see above for details.
Unloading Young's Modulus
Unloading Young's Modulus can be defined as a Datum Dependent property for materials with Use Unloading Condition = Yes. The following input properties of datum dependency will be applied to unloading young's modulus.