CiviLab 7.1 processes the triaxial test from the readings of each specimen (typed or imported from Excel) and produces the complete test sheet. Standards applied:
- NF EN ISO 17892-8:2018 — unconsolidated undrained test (UU);
- NF EN ISO 17892-9:2018 — consolidated tests CU / CIU, CAU and drained tests CD / CID, CAD;
- NF P 94-070 — interpretation (failure criteria, c′ and φ′).
CiviLab allows you to:
- calculate the corrected area and the membrane and filter-paper corrections;
- calculate total and effective stresses and the B coefficient = Δu/Δσc (warning if B < 0.95);
- choose the failure criterion: maximum deviator stress, maximum σ′v/σ′h ratio or limiting strain (15 % without peak);
- obtain c′ and φ′ by the regression t = k + s′·tan α′ (NF P 94-070, annex B), or the undrained shear strength cu = (σv − σh)f/2;
- plot the deviator stress and Δu (or volumetric strain) against axial strain, the Mohr circles with the failure envelope, and the t – s′ stress paths;
- work in SI or US units, import and export readings (Excel / CSV) and export results to AGS4.
Validation on published tests
- British Geological Survey (report IR/06/065): 4 CIU tests — published c′ and φ′ reproduced within 0.01;
- University of Waterloo (Winnipeg clay): 4 CD tests from the raw readings — φ′ = 17.97°, c′ = 26.14 kPa, identical to the independent calculation;
- UU test: equations (1) to (6) of NF EN ISO 17892-8 checked by hand.