Ground Support & Reinforcement
Add anchors, geosynthetics, piles, and other reinforcement.
Ground support represents reinforcement that resists slope failure: anchors, tiebacks, soil nails, geosynthetic layers, and piles. Each support is drawn on the model as a two-point line and assigned a support material that defines its capacity and how its force is applied.
Workflow
- Define one or more support materials in the support catalog and choose the support type for each.
- Draw the support on the model as a line between two points.
- Assign a support material to the drawn support.
Where the support line crosses a slip surface, the reinforcement contributes a force to the limit-equilibrium solution.
Active vs. passive force
Every support material applies its force as either active or passive:
- Active (Method A) — the support force is treated as a known applied load that helps drive equilibrium. It is included with the loads, reducing the demand the soil must resist.
- Passive (Method B) — the support force is treated as added shear resistance mobilized along the slip surface, increasing the available strength.
The two methods can yield different factors of safety; choose the one consistent with your design approach. Each support type has a default, listed below.
Force orientation
For all support types except piles, the reinforcement force can be oriented as:
| Option | Description |
|---|---|
| Parallel to Reinforcement | Along the support line. |
| Tangent to Slip Surface | Along the slip surface at the crossing point. |
| Bisector of Parallel and Tangent | Bisector of the parallel and tangent directions. |
| Horizontal | Horizontal. |
| User-defined Angle | At a specified angle (degrees). |
Piles instead choose between Tangent to Slip Surface and Perpendicular to Pile.
Support types
Capacities and strengths below are entered in the model's force/length units; spacing is out-of-plane (into the page).
End-Anchored
A bar or cable anchored at its far end, contributing tensile force.
| Parameter | Unit | Default | Description |
|---|---|---|---|
| Out-of-plane spacing | m | 1 | Horizontal spacing between anchors out-of-plane. |
| Tensile capacity | kN | 100 | Maximum tensile force the anchor can carry. |
| Force orientation | — | Parallel to Reinforcement | See orientation options above. |
Default force application: Active.
Grouted Tieback
A tensioned anchor with a grouted bond zone; force is limited by tensile, plate, and bond capacities.
| Parameter | Unit | Default | Description |
|---|---|---|---|
| Out-of-plane spacing | m | 1 | Horizontal spacing between tiebacks out-of-plane. |
| Bond length mode | — | Percentage | Whether bond length is given as a percentage of the support length or as an absolute length. |
| Bond length | % or m | 100 (%) | Bond zone length. As a percentage when in percentage mode; as a length in actual mode. |
| Tensile capacity | kN | 100 | Maximum tensile force in the tendon. |
| Plate capacity | kN | 100 | Capacity at the face plate. |
| Bond strength | kN/m | 10 | Bond resistance per unit length of the bond zone. |
| Force orientation | — | Parallel to Reinforcement | See orientation options above. |
Default force application: Active.
Soil Nail
A passive, fully bonded reinforcement that mobilizes force as the soil deforms.
| Parameter | Unit | Default | Description |
|---|---|---|---|
| Out-of-plane spacing | m | 1 | Horizontal spacing between nails out-of-plane. |
| Tensile capacity | kN | 100 | Maximum tensile force in the nail. |
| Plate capacity | kN | 100 | Capacity at the face plate. |
| Bond strength | kN/m | 10 | Bond resistance per unit length. |
| Force orientation | — | Parallel to Reinforcement | See orientation options above. |
Default force application: Passive.
Geosynthetic
A reinforcing strip or sheet (geotextile/geogrid), with capacity governed by tensile strength, coverage, anchorage, and pullout.
| Parameter | Unit | Default | Description |
|---|---|---|---|
| Tensile strength | kN/m | 100 | Long-term tensile strength of the reinforcement. |
| Strip coverage | % | 100 | Fraction of the area covered by reinforcement strips. |
| Anchorage | — | Slope Face | Where pullout resistance is developed: None, Slope Face, Embedded End, or Both Ends. |
| Connection strength | kN/m | 100 | Strength of the connection at the slope face. |
| Adhesion | kN/m² | 0 | Adhesion component of pullout resistance. |
| Friction angle | degrees | 30 | Friction component of pullout resistance (0 ≤ φ < 90). |
| Force orientation | — | Parallel to Reinforcement | See orientation options above. |
Default force application: Passive.
Pile
A structural pile resisting the sliding mass in shear.
| Parameter | Unit | Default | Description |
|---|---|---|---|
| Out-of-plane spacing | m | 1 | Horizontal spacing between piles out-of-plane. |
| Pile shear strength | kN | 100 | Shear capacity the pile provides across the slip surface. |
| Force orientation | — | Tangent to Slip Surface | Tangent to Slip Surface or Perpendicular to Pile. |
Default force application: Passive.
Note A drawn support must have two endpoints and be assigned a valid support material before the analysis will run. Spacing, capacity, and strength values must be valid (spacing greater than zero; capacities and strengths zero or greater; geosynthetic friction angle at least 0 and less than 90 degrees).