Multiple Joint Combinations

The Joint Combinations option allows you to select and analyze different combinations of joint planes within the same UnWedge file if your input data includes more than three possible joint planes. The selection of combinations can be done manually, or the Combination Analyzer can be used for a Deterministic Analysis to help you determine which are the most critical combinations of joints to analyze. For a Probabilistic Analysis, the Compute All Joint Combinations option can be used.

To use this option:

1. Select the Joint Orientations tab in the Input Data dialog.
2. The Joint Combinations option is only applicable if you have more than 3 joints defined in the Input Data dialog. To create new joints
   • Select the Add button for each new joint that you require, and enter the joint orientations, or
   • Use the Import from Dips option to import a Dips file, which may contain any number of joints.
3. When more than three joints are defined, you will be able to select any combination of three joints, using the Joint Combinations option. The selection of combinations can be done manually (as described below), or the Combination Analyzer can be used for a Deterministic Analysis to help you determine which are the most critical combinations of joints to analyze. For a Probabilistic Analysis, the Compute All Joint Combinations option can be used.
4. To manually analyze different joint combinations:
   • Use the drop-down list boxes to select any combination of 3 joints, by selecting the joint ID numbers (e.g. joints 1,2 and 4), or
   • Use the spinner control to automatically cycle through all possible combinations of three joints. The total number of possible combinations of three joints will be indicated in the dialog, based on the total number of joints which are defined. The number of distinct combinations is given by the formula:



Where:

• n = the number of joints
• N = the number of combinations

(Example: if 5 joints are defined, then the number of combinations = 5!/(3! 2!) = 10)

5. When you select joint combinations, notice that the Stereonet View at the right of the dialog is automatically updated. The three currently selected joints will be highlighted in colour on the Stereonet. All other (unused) joints will be displayed in grey on the stereonet.
6. Once you have selected a joint combination, then you can view the results in UnWedge. Only the 3 selected joints will be considered in the analysis. The unused joints will have no effect on the analysis.
7. Repeat these steps for each combination of 3 joints that you wish to analyze.
8. To automatically analyze all possible combinations for a Deterministic Analysis, select the Combination Analyzer option. For a Probabilistic Analysis, select the Compute All Joint Combinations option.

Joint Numbering

If you are using the Joint Combinations option to select joints, the joint ID numbering from the Input Data dialog, will be used throughout the program to identify the joints (e.g., joints 1, 2, 4, joints 2,3,5, etc.). This applies to the Info Viewer, Wedge Information panel in the Sidebar, Data Tips, etc.

Display of Unused Joints on Stereonet

When you have more than three joint orientations defined in the Input Data dialog, the "unused" joints can be displayed on the stereonet in gray. You can toggle the display of the unused joints on the stereonet on or off in the Display Options dialog. Select Display Options, and under the General tab, toggle the Show Unused Joints on Stereonet checkbox.