Spacing

Source file: discontinuity-spacing.htm

The discontinuity spacing tool enables you to build a simple map of spacings between discontinuities. The tool allows you to specify the size to use for comparing overlaps of discontinuities, then examine the spacings between discontinuities with reference to an average orientation or a specific orientation of interest. The graphical results are stored in the geotechnical container. The report window also displays statistics for individual discontinuity sets, along with a final grouping of all discontinuities. You can save a list of the spacings to a text file.

Start with discontinuities that you've investigated using Extract discontinuities, Query dip and strike, or saved previously.
You can assess multiple sets of discontinuities in one operation. Results will be given for each set as well as for all discontinuities combined.

• To analyse discontinuity spacing, proceed as follows:

  1. On the Geotechnical tab, in the Analyse group, click Spacing.

  2. Add existing discontinuity sets or individual discontinuities to the Discontinuity selection list by selecting the discontinuities and clicking or by dragging the discontinuities into the field. To remove an entry, select the discontinuity and click .

     

  3. Adjust settings to refine your analysis. The following are available to help define the theoretical sizes of discontinuities or exclude certain spacings.

  • Select from the following optional settings as required:

    • Minimum spacing: Spacing less than this value will be ignored.
    • Maximum spacing: Spacing greater than this value will be ignored.

  • Choose one of the following methods to define the size of the discontinuities for the purpose of the analysis:

    • Assume discontinuities are infinite in size: Select this to treat discontinuities as infinite planes.
    • Use the current discontinuity geometry: Select to count only discontinuities that exactly intersect the orientation line.
    • Specify diameter: Select to treat discontinuities as circular discs of the specified diameter, located at their current centroids.
  • Choose whether to use an orientation line and specify its location. If you specify an orientation line, spacing will be calculated as the distance between discontinuities at the location they intersect the orientation line. Without an orientation line, spacing will be calculated based on the mean discontinuity orientation. Enter coordinates directly into the fields on the panel or select the fields and click in the view window where you want to define the orientation line.

  4. Click OK or Apply.

New sets of discontinuities will be created at the locations of the input discontinuities, but oriented to the mean direction of the discontinuity set. Lines representing the spacings between the nearest discontinuities are created, according to the criteria entered. Right-click on a discontinuity and chose View Front On or View Side On to see these angles accurately (ensure you are in orthographic projection mode, not perspective).

Note:   Spacings (represented by lines) can be deleted by manually selecting and removing them in the view window.

Tip:  Press Ctrl+ I to recalculate and update the properties, rather than running the Discontinuity Spacing tool again. This can be useful after cleaning up data and deleting incorrect lines. Delete all incorrect lines, select the remaining lines.

The summary of statistics for individual discontinuity sets (if present) as well as a final grouping of all discontinuities will be presented in the report window.

Tip:  Use the visibility editor to help differentiate elements to display.

• To save the spacings to a text file follow these steps:

  1. Select the Measurement lines sub-container in the discontinuity spacing of <name> container.

     

  2. From the Home tab, in the Data group, click Export.

  3. Set Export as as custom text file and the unit to export in.

     

  4. Click OK or Apply.

     

  5. In the Export custom ASCII format panel set the ASCII format type to New format... from the drop-down list.

  6. Set Export data to Edge properties.

  7. Click OK.

     The discontinuity spacings are exported as a text file.