Joint Inputs and Analysis Modes
Enter joint strengths and orientations for single, combination, and probabilistic analyses.
Joint Setup
| Input | Range/units | Description |
|---|---|---|
| Enable joint scaling | On/off | Shows and applies joint length controls. Surface geometry is adjusted around entered maximum lengths; underground candidates are trimmed by the per-joint persistence distances. |
| Analysis Mode | Surface: Single, Combinations, Probabilistic. Extruded underground: Combinations, Probabilistic; Tunnel Intersection: Single | Controls whether the app evaluates one case, variable joint-set combinations, or deterministic samples from distributions. |
| Active Joint Set | Joint set list | Selects which joint set inputs are shown in Combinations and Probabilistic modes. Result-set modes can add more than the minimum required joint sets. |
| Joint colour swatch | Hex colour picker | Sets the displayed colour for that joint set in setup cards, stereonets, and 3D joint faces/traces. Default colours remain unchanged until edited. |
| Dip / Mean Dip | 0 to 90 degrees | Joint plane inclination. In probabilistic mode this is the mean orientation. |
| Dip Direction / Mean Dip Direction | 0 to 360 degrees | Azimuth toward which the joint dips. In probabilistic mode this is the mean orientation. |
| Length / Mean Length | >= 0.1 m | Maximum joint trace/face length used when joint scaling is enabled. |
| Cohesion / Mean Cohesion | kPa | Joint cohesion used for shear resistance. |
| Friction Angle / Mean Friction Angle | 0 to 90 degrees | Joint friction angle used for shear resistance and kinematic reserve. |
Single Mode
Single mode uses two joints for surface wedge sliding or one failure plane for planar sliding. Tunnel Intersection always uses exactly three direct joint cards with orientation, strength, colour, and optional persistence length. It searches the same eight three-joint and twelve two-joint block families across all junction regions, so a Single analysis may recover many wedges. Set/row management and probabilistic distributions apply only to extruded underground analyses.
Combinations Mode
| Function | Description |
|---|---|
| Active Joint Set | Shows one joint-set orientation table at a time. Hidden joint sets remain part of the result set. |
| Add Joint Set / Remove Active Set | Adds a new set copied from the active set, or removes the active set down to the mode minimum: two sets for surface, three for underground. |
| Strength Values | Chooses whether cohesion and friction angle are entered once per set or independently per orientation row. |
| Length Values | When joint scaling is enabled, chooses whether length is entered once per set or independently per orientation row. |
| Orientation Table | Surface evaluates every unordered joint-set pair and every row pair inside each set pair. Underground evaluates every unordered joint-set triplet, every row triplet inside each set triplet, and all eight block codes. |
| Add Row | Adds a new orientation row seeded from the last row. |
| Remove row | Removes an orientation row. Disabled when only one row remains. |
| Paste table data | Cells may be pasted from tab, comma, or space separated text into the visible columns: Dip, Dip Direction, optional Cohesion, optional Friction Angle, and optional Length. |
In underground Combinations mode, every active three-set selection uses the same set/row scope controls as surface Combinations mode. The app evaluates every unordered triplet of joint sets and all eight block-code candidates for each row group.
Underground Joint Scaling
In underground Combinations mode, Enable joint scaling adds Length Values controls. Set-level length applies to every row in that set; per-orientation length adds a Length column to the active table. In underground Probabilistic mode, scaling adds Persistence controls to each probabilistic joint set card. Selected underground candidates are trimmed by the configured one-sided persistence distance into the rock before the wedge is recovered.
Probabilistic Mode
| Input | Range/units | Description |
|---|---|---|
| Active Joint Set | Joint set list | Shows one probabilistic joint-set input card at a time. |
| Add Joint Set / Remove Active Set | Adds a new set copied from the active set, or removes the active set down to the mode minimum: two sets for surface, three for underground. | |
| Samples | 1 to 50,000 | Number of deterministic samples generated for each unordered surface pair or underground triplet. |
| Seed | 0 to 4,294,967,295 | Seed for repeatable sample generation. Same inputs and seed produce the same samples. |
| Fisher K | >= 0 | Concentration parameter for sampled plane orientation around the mean pole. Larger values produce tighter orientation clustering. |
| Std Dev | Input units | Standard deviation for cohesion, friction angle, or length. |
| Relative Min | Input units | Lower bound relative to the mean for sampled values. |
| Relative Max | Input units | Upper bound relative to the mean for sampled values. |
Surface probabilistic mode samples every unordered joint-set pair independently. Underground probabilistic mode samples every unordered joint-set triplet independently, including each joint set's cohesion and friction angle, then evaluates all eight block-code candidates for each sampled triplet.
The configured sample range is also subject to the 50,000 retained-result budget across the active model. Every surface pair contributes one result per sample; every underground triplet contributes eight block-code results per sample. Adding joint sets therefore lowers the largest computable sample count. The setup footer and Compute button report an over-budget draft explicitly; results are never truncated.