Rock mechanical properties

The Geotechnical Rock Testing Facility aims to investigate the mechanical and physical properties of near-surface rocks (less than 5 km deep) and building stones to the suggested ISRM (2007) and ASTM (1995) standards. The facility performs a range of classification (index), strength and deformation tests on core samples with diameters of 38 mm, 50 mm and 100 mm to ASTM (1995) standards.

Triaxial compressive strength and deformability testing with vertical and horizontal strain measurement on prepared rock core
Uniaxial compressive strength and deformability testing with vertical and horizontal strain measurement on prepared rock core

Triaxial and uniaxial strength and deformation testing are conducted on samples with diameters of 38 mm, 50 mm and 100 mm in a 2 000 Kn or 4 500 kN load frame. For triaxial testing, Hoek-Franklin cells are used and the confining pressures and axial loads are controlled and logged independently. The triaxial and uniaxial deformation tests are undertaken using Vishay electrical strain-gauges, which monitor the axial and lateral strain through out the deformation test, and are digitally logged using the the Vishay System 5000 Strain Indicator and Recorder.

Point load test on rock core
Sonic (P) wave velocity measurements of prepared rock core

Intact rock testing undertaken at BGS's Geotechnical Rock Testing Facility includes:

  • index (density, effective porosity, and moisture content)
  • uniaxial strength
  • uniaxial deformation
  • triaxial strength
  • triaxial deformation
  • indirect compressive strength
  • direct shear strength (portable rock shear box)
  • indirect tensile strength (Brazilian disc method)
  • 3D swelling strain
  • slake durability
  • point load
  • sound velocity (P and S wave)

Contact

Please contact Dr Helen Reeves for further information