The Stability module of CiviLab 7.1 has its own ribbon tab, organised in four groups: Bishop method, Spencer / Morgenstern-Price, Non-circular surfaces and Seismic. Each group has its own input window, list of calculations and sheets.
Pseudo-static seismic analysis
- RPA 2024 §10.3: kh = A·I·S·ST/3 (10.22); kv = ±kh/2 in zones IV to VI (type 1) or ±kh/3 in zones I to III (type 2) (10.23); A table 3.2, I table 3.10, S tables 3.3 / 3.4, ST annex C;
- seismic forces applied to the soil and to the supported loads; required F = 1.15 (§10.3.6);
- NF P 94-270 annex I.4: kh = ½·(ag/g)·S·ST; kv = ±0.5·kh if avg/ag > 0.6, ±0.33·kh otherwise;
- or user-defined kh and kv;
- force kh·W at the centre of gravity of each slice, both signs of kv calculated, most unfavourable combination retained;
- calculation by Bishop, Spencer or Morgenstern-Price.
Geometry and soils
- soil layers defined by their top boundary, with γ, γsat, c′ / φ′ (drained) or cu (undrained);
- water table and surcharge at the crest;
- input window with a permanent scaled section and Excel import / export.
Eurocode 7 check
- factor of safety F compared with the required factor;
- NF P 94-270 §10: design approach 3 (A2 + M2 + R3), partial factors of annex C (γQ = 1.3; γφ′ = 1.25; γc′ = 1.25; γcu = 1.4), γR;d = 1.10 (§10.5), inequality 10.2.1 Fd ≥ γR;e·γR;d.
Results
- scaled sheet: layers, water table, surcharge, critical surface and slices, soil table and results;
- comparison Fellenius / Bishop / Spencer / Morgenstern-Price (with λ) on the critical surface;
- "Test data" pages with the slices of the critical surface.
Validation on published cases
Each published case was entered in CiviLab and compared with the reference value and with the GeoStudio SLOPE/W results (verification manual). Difference = (CiviLab − GeoStudio) / GeoStudio, same method.
| Case | Method | Published reference | GeoStudio | CiviLab 7.1 | Difference / GeoStudio |
|---|---|---|---|---|---|
| ACADS — non-homogeneous slope, seismic kh = 0.15 | Bishop | 1.00 | 1.016 | 1.011 | −0.5 % |
| ACADS — non-homogeneous slope, seismic kh = 0.15 | Spencer | 1.00 | – | 0.984 | – |
| ACADS — non-homogeneous slope, seismic kh = 0.15 | Morgenstern-Price | 1.00 | 0.989 | 0.983 | −0.6 % |
| Calculation | Expected | CiviLab |
|---|---|---|
| Infinite slope, kh = 0.10 (analytical solution) | 1.1087 | 1.1093 (+0.05 %) |
| RPA 2024, zone III, group 2, site S3: kh; kv | 0.0775; 0.02583 | identical |
| RPA 2024, zone V, group 1B, site S2, ST = 1.2: kh; kv | 0.1440; 0.0720 | identical |
| RPA 2024 §10.3.6: required F | 1.15 | 1.15 |
| NF P 94-270 I.4, ag/g = 0.2, S = 1.2: kh; kv (avg/ag = 0.9 then 0.5) | 0.12; 0.06; 0.0396 | identical |
| Excel recalculation, ACADS 1(a), kh = 0.15: Fellenius; Bishop; Spencer | 0.68711; 0.71586; 0.71711 | 0.68711; 0.71586; 0.71711 |