BS 8006
BS 8006-1:2010 Section 7 — Reinforced Slopes
BS 8006-1:2010+A1:2016Revision 2Required FoS ≥ 1
Use it in Slope
In a design, choose it under Analyze → Design factor set, and the PDF report runs it too. It runs several checks: to change one, copy that check from the library's New set.
Checked against the standard · Slope convention · Not yet validated
The governing check is the one with the highest utilisation (G3); the wet-slope check runs when r_u > 0.15 anywhere or a water table crosses the reinforced zone.
Known limitations
- The ultimate limit state check always runs; the wet-slope check (FoS ≥ 1.3) runs only when the slope is wet (7.2.6). The result is the check with the higher utilisation.
Scope
- Soil nails: BS 8006-1 Section 7 covers reinforcement placed in fill, not soil nails — design them to BS 8006-2.
Ultimate limit state — required FoS ≥ 1
Checked against the standard · Not yet validated
Known limitations
- Table 21 gives ultimate values only; a helping dead load is taken at ×1.0 and a helping live load at ×0 (Slope convention, not the standard's).
- A1:2016 deleted the 7.4.4.3 slices equation; ffs on the whole slice weight with the pore pressure scaled follows 7.2.1 and Figure 82 (medium confidence).
- Layer rupture is divided by the fm entered on each element (7.2.3, Annex A); Annex A.2.2 gives fm = 1.50 for plain or galvanised steel in axial tension only.
- Direct sliding across a layer takes a′·tanφ′p/fms and a′bc·c′/fms ÷ fs (6.5.3 form); fn does not apply.
- Anchors, soil nails and piles are outside Section 7 and are unfactored; design soil nails to BS 8006-2.
- Surfaces wholly outside the reinforcement should be checked to BS EN 1997-1 and its UK National Annex (7.4.3); Slope flags them.
- Other strength models (Hoek–Brown, hyperbolic) are unfactored.
Values
Actions
| Soil weightγ | Unfavorable | ×1.50 |
| Favorable | ×1.50 | |
| Permanent loadγG | Unfavorable | ×1.20 |
| Favorable | ×1.00 | |
| Variable loadγQ | Unfavorable | ×1.30 |
| Favorable | ×0.00 | |
| Seismic coefficientγE | ×1.00 | |
Resistance
| Earth / global resistanceγRe | ÷1.00 | |
Materials
| Effective cohesionγc′ | ÷1.60 | |
| Friction (tanφ′)γφ | ÷1.00 | |
| Undrained strength (cu)γcu | ÷1.00 | |
| Shear strength (other models)— | ÷1.00 | |
Reinforcement
| Geosynthetic — ruptureγt | ÷1.00 | |
| Geosynthetic — pull-outγpo | ÷1.30 | |
| Geosynthetic — sliding acrossfs | ÷1.30 | |
| Steel strip — ruptureγt | ÷1.00 | |
| Steel strip — pull-outγpo | ÷1.30 | |
| Steel strip — sliding acrossfs | ÷1.30 | |
| Steel grid — ruptureγt | ÷1.00 | |
| Steel grid — pull-outγpo | ÷1.30 | |
| Steel grid — sliding acrossfs | ÷1.30 | |
Sources
Document: BS 8006-1:2010+A1:2016
Actions
| Factor | Value | Source |
|---|---|---|
| Soil weight — unfavorable | ×1.50 | 7.2.1, Table 21, ffs, PDF p145 · Slope convention · Not yet validated — ffs multiplies the whole slice weight (single source), and the pore pressure with it. A1:2016 deleted the 7.4.4.3 slices equation; 7.2.1 and Figure 82 (8.3.2.5) support this reading. |
| Soil weight — favorable | ×1.50 | 7.2.1, Table 21, ffs, PDF p145 · Slope convention · Not yet validated — ffs multiplies the whole slice weight (single source), and the pore pressure with it. A1:2016 deleted the 7.4.4.3 slices equation; 7.2.1 and Figure 82 (8.3.2.5) support this reading. |
| Permanent load — unfavorable | ×1.20 | 7.2.2, Table 21, ff, PDF p145 · Not yet validated |
| Permanent load — favorable | ×1.00 | 7.2.2, Table 21, PDF p145 · Slope convention · Not yet validated — The table gives ultimate values only (its 1.0 is the serviceability column); a helping dead load is taken at ×1.0. |
| Variable load — unfavorable | ×1.30 | 7.2.2, Table 21, fq, PDF p145 · Not yet validated |
| Variable load — favorable | ×0.00 | 7.2.2, Table 21, PDF p145 · Slope convention · Not yet validated — Table 21 gives no favourable factor; a helping live load is omitted (cf. walls Table 12 combination B, fq = 0). |
| Seismic coefficient | ×1.00 | Annex F, PDF p245 · Slope convention · Not yet validated — Annex F (informative) proposes no seismic method or partial factor. |
Materials
| Factor | Value | Source |
|---|---|---|
| Effective cohesion | ÷1.60 | 7.2.3, Table 21, fms on c′, PDF p145 · Not yet validated |
| Friction (tanφ′) | ÷1.00 | 7.2.3, Table 21, fms on tan φ′p, PDF p145 · Not yet validated |
| Undrained strength (cu) | ÷1.00 | 7.2.3, Table 21, PDF p145 · Slope convention · Not yet validated — Table 21 has no cu row; Section 6 Table 11 and Section 8 Table 22 give fms = 1.0. |
| Shear strength (other models) | ÷1.00 | 7.2.3, Table 21, PDF p145 · Slope convention · Not yet validated — BS 8006 gives no factor for other strength models; they are unfactored. |
Resistance
| Factor | Value | Source |
|---|---|---|
| Earth / global resistance | ÷1.00 | 7.2.1, Table 21, PDF p145 · Not yet validated |
Reinforcement
| Factor | Value | Source |
|---|---|---|
| Geosynthetic — rupture | ÷1.00 | 7.2.3, Table 21: fm consistent with the reinforcement and design life, PDF p146 · Not yet validated |
| Geosynthetic — pull-out | ÷1.30 | 7.2.4, Table 21, fp, PDF p145 · Not yet validated |
| Geosynthetic — sliding across | ÷1.30 | 7.2.4, Table 21, fs, PDF p145 · Not yet validated |
| Steel strip — rupture | ÷1.00 | 7.2.3, Table 21: fm consistent with the reinforcement and design life, PDF p146 · Not yet validated |
| Steel strip — pull-out | ÷1.30 | 7.2.4, Table 21, fp, PDF p145 · Not yet validated |
| Steel strip — sliding across | ÷1.30 | 7.2.4, Table 21, fs, PDF p145 · Not yet validated |
| Steel grid — rupture | ÷1.00 | 7.2.3, Table 21: fm consistent with the reinforcement and design life, PDF p146 · Not yet validated |
| Steel grid — pull-out | ÷1.30 | 7.2.4, Table 21, fp, PDF p145 · Not yet validated |
| Steel grid — sliding across | ÷1.30 | 7.2.4, Table 21, fs, PDF p145 · Not yet validated |
Wet slope (7.2.6) — required FoS ≥ 1.3 · applies to wet slopes only
Checked against the standard · Slope convention · Not yet validated
"Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3.
Known limitations
- Runs when r_u > 0.15 anywhere or a water table crosses the reinforced zone (7.2.6).
- Soil, loads and pull-out are unfactored and fn is not applied; layer rupture is divided by the element's fm (Slope convention).
Values
Actions
| Soil weightγ | Unfavorable | ×1.00 |
| Favorable | ×1.00 | |
| Permanent loadγG | Unfavorable | ×1.00 |
| Favorable | ×1.00 | |
| Variable loadγQ | Unfavorable | ×1.00 |
| Favorable | ×1.00 | |
| Seismic coefficientγE | ×1.00 | |
Resistance
| Earth / global resistanceγRe | ÷1.00 | |
Materials
| Effective cohesionγc′ | ÷1.00 | |
| Friction (tanφ′)γφ | ÷1.00 | |
| Undrained strength (cu)γcu | ÷1.00 | |
| Shear strength (other models)— | ÷1.00 | |
Reinforcement
| Geosynthetic — ruptureγt | ÷1.00 | |
| Geosynthetic — pull-outγpo | ÷1.00 | |
| Steel strip — ruptureγt | ÷1.00 | |
| Steel strip — pull-outγpo | ÷1.00 | |
| Steel grid — ruptureγt | ÷1.00 | |
| Steel grid — pull-outγpo | ÷1.00 | |
Sources
Document: BS 8006-1:2010+A1:2016
Actions
| Factor | Value | Source |
|---|---|---|
| Soil weight — unfavorable | ×1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Soil weight — favorable | ×1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Permanent load — unfavorable | ×1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Permanent load — favorable | ×1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Variable load — unfavorable | ×1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Variable load — favorable | ×1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Seismic coefficient | ×1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
Materials
| Factor | Value | Source |
|---|---|---|
| Effective cohesion | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Friction (tanφ′) | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Undrained strength (cu) | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
| Shear strength (other models) | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
Resistance
| Factor | Value | Source |
|---|---|---|
| Earth / global resistance | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — "Conventional limit equilibrium" is read as unfactored soil and loads with a lumped FoS ≥ 1.3. |
Reinforcement
| Factor | Value | Source |
|---|---|---|
| Geosynthetic — rupture | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — The reinforcement enters at its design strength TD = Tchar / fm (7.2.3); the lumped FoS of 1.3 covers the rest. |
| Geosynthetic — pull-out | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — A conventional analysis applies no pull-out factor; the lumped FoS of 1.3 covers it. |
| Steel strip — rupture | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — The reinforcement enters at its design strength TD = Tchar / fm (7.2.3); the lumped FoS of 1.3 covers the rest. |
| Steel strip — pull-out | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — A conventional analysis applies no pull-out factor; the lumped FoS of 1.3 covers it. |
| Steel grid — rupture | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — The reinforcement enters at its design strength TD = Tchar / fm (7.2.3); the lumped FoS of 1.3 covers the rest. |
| Steel grid — pull-out | ÷1.00 | 7.2.6, PDF p146 · Slope convention · Not yet validated — A conventional analysis applies no pull-out factor; the lumped FoS of 1.3 covers it. |