Rock Mechanics Testing
Unconfined Compressive Strength Testing
The simplest of the laboratory geomechanics tests, giving a measure of strength together with Young’s Modulus and Poisson’s Ratio. No confining pressure and no pressure vessel — unconfined strength.
What you receive
- Unconfined compressive strength (peak stress)
- Young’s Modulus
- Poisson’s Ratio
- Full stress-strain plot
Sample diameter 0.75″ to 4″, length twice the diameter per ASTM/ISRM standard. Common sizes: 1″ × 2″ and 1.5″ × 3″.
- Rock strength underpins any field development decision — drilling a wellbore, designing a hydraulic fracture, or assessing the mechanical behaviour of a reservoir already producing.
- UCS is usually the first measurement made, because it is quick and it constrains everything that follows.
- Peak stress achieved during the test is reported as the UCS of the sample.
- Young’s Modulus is taken as the slope of the stress-strain plot through the linear-elastic region, after any micro-cracks have closed and before yield, so the value reflects elastic behaviour rather than early compaction.
