Discrete Strength Function

A Discrete Strength Function allows you to specify the shear strength at discrete x,y locations throughout a material. The shear strength at any point within the material can then be interpolated. Shear strength may be specified for either the undrained case (cohesion only), or drained (cohesion and friction angle).

To define a Discrete Strength Function:

1. Set the Strength Type = Discrete Function in the Define Material Properties dialog.
2. Select the New button.
3. You will see the Define Discrete Strength Function dialog.
4. Enter a Function Name.
5. Select the Function Type – Undrained (phi=0) or Drained (c, phi).
6. Enter the Discrete Strength Function data in the data entry grid.
• If the Function Type = Undrained, you will be able to enter the undrained Cohesion (Cu) at X,Y coordinates.
• If the Function Type = Drained, you will be able to enter drained Cohesion and Phi at X,Y coordinates.
You can use the buttons at the top of the data entry grid to help carry out editing of the data (i.e. insert row, remove row, copy, paste etc.)
7. Select an Interpolation Method. This will determine the method used to interpolate the strength parameters at any point in the material. For details about the various Interpolation Methods, see the Interpolation Method topic in the Project Settings section of this Help system.
If your material is Drained, the Interpolation is performed independently for Cohesion and friction angle Phi.
8. You can also select the type of Symbol and colours which are used to display the location of the Discrete Strength function data points on the model.
9. When all data points have been entered, select OK, and you will be returned to the Define Material Properties dialog. The Name of the function you have just defined will appear in the Discrete function list. By selecting a Function Name from this list, you can now apply a Discrete Function to any material in the model.

Import/Export Discrete Strength Functions

Discrete Functions can be Exported (saved) in a separate functions file, and Imported into other Slide2 files, so that you do not have to re-define a Discrete Function if it is required for another Slide2 file.

Discrete Function files in Slide2 use a .FN6 filename extension.

To Export (save) a Discrete Function:

10. Select the Export button in the Define Discrete Strength Function dialog.
11. In the Save As dialog, enter a filename and save the file.
The default filename will use the Function Name, but this can be changed if required.

To Import a Discrete Function:

12. Select the Import button in the Define Discrete Strength Function dialog.
13. In the Open File dialog, open the Discrete Function file that you wish to import, and it will be imported into the Define Discrete Function dialog. File formats which can be imported include:
• Comma, Tab or Space delimited text files
• *.FN6 function files created with the Export option
• *.DXF files
14. Select OK to add this function to the list of currently defined Discrete Strength Functions in the current model.

Display of Discrete Strength Function

When a Discrete Strength Function has been defined for a material, the function will be displayed on the model by a symbol located at each x,y location defined in the function. The Symbol used for the function is the symbol selected in the Define Discrete Strength Function dialog. The strength function value(s) at each location, can be displayed by selecting the checkbox in the Display Options dialog.

In the Slide2 Interpret program, approximate contours of the interpolated Discrete Function can be displayed on the model by selecting the Supplemental Contours option in the Data menu.

The interpolation results should always be looked at to ensure that the interpolation correctly simulates your field data. If it does not, then either more data points should be used or a different interpolation technique. Since no interpolation method is guaranteed to work for all datasets, different methods should be tried in order to determine the best method for your data.