Shear and oedometer (compression) tests
Angle of internal friction, cohesion, deformation modulus and collapse properties — key inputs for foundation bearing capacity and settlement.
Licensed service · EL-845/2026
Foundation design for bearing capacity and settlement relies on two groups of mechanical parameters: strength (angle of internal friction and cohesion) and deformability (deformation modulus and compressibility). Both are determined in the laboratory by shear and oedometer tests.
In a direct shear test, an undisturbed sample is sheared along a horizontal plane under several normal loads. The peak shear stress is recorded for each load and the friction angle and cohesion are derived from the Mohr–Coulomb relationship. Depending on design conditions, the test is run as consolidated-drained or quick, at natural moisture or after saturation.
In an oedometer (one-dimensional compression) test, the sample is loaded in increments without lateral expansion and deformation is measured at each stage until it stabilises. A compression curve is plotted and the deformation modulus and coefficient of compressibility are calculated. For the loess-like soils found on the Absheron peninsula, collapse on wetting and the initial collapse pressure are determined; for expansive clays, the swelling pressure is measured.
Tests are performed on calibrated equipment in line with applicable standards (GOST, AzDTN/SNiP), and results are statistically processed for each engineering-geological unit.
When you need it
- Foundation bearing capacity design
- Settlement analysis of buildings and structures
- Stability analysis of slopes and retaining walls
- Study of collapsible (loess-like) and expansive soils
- Strengthening or extending existing buildings
What's included
- Trimming specimens from undisturbed samples
- Direct shear tests under several normal loads
- Calculating friction angle and cohesion
- Incremental-load oedometer test
- Determining deformation modulus and compressibility
- Collapse and swelling properties where required
How we work
- Agreeing the test scheme with the designer
- Sample receipt and specimen preparation
- Shear and oedometer testing
- Processing and statistical analysis
- Issue of certificates and charts
Deliverables
- Shear plots and strength parameters
- Compression curves and deformation modulus
- Collapse and swelling indicators where required
- Table of characteristic and design values
- Test certificates
