The Rock Mechanics and Physics Laboratory (RMPL)

MTS 815 load frame equipped with confining pressure vessel with hood up (LHS) and hood down (RHS).

The Rock Mechanics and Physics Laboratory (RMPL) undertakes research on the physical properties and behaviour of rock specifically for: planning, design and construction within the civil engineering sector; extraction and storage within the energy sector; developing our understanding of near–surface to shallow crustal earth processes in order to help predict and mitigate the effects of small and large scale geohazards.

The RMPL lab specialises in standard (ISRM and ASTM) and bespoke geomechanical and rock physics testing, including measurement of strength (triaxial and uniaxial), deformability, thermal properties, geophysical properties, sonic velocity, permeability, porosity and density.

RMPL is the home of BGS's large scale rock deformation apparatus which is used to measure the physical properties and behaviour of rock when subjected to changes in pressure and temperature associated with near surface to shallow crustal conditions (˜6 km). The system comprises an MTS 4.6 MN capacity servo–controlled hydraulic load frame, triaxial pressure vessel, confining pressure intensifier unit (140 MPa), a pore pressure intensifier unit (70 MPa total pressure and 35 MPa differential pressure) and heating system (200 °C). The rock deformation apparatus is able to make synchronous measurement of stress, strain, sonic velocity, acoustic emission and permeability during deformation.

Recent studies have focused on the geomechanical parameters of: reservoir (sandstone) and cap rocks (mudstone) from Carbon Capture & Storage (CCS) sites in the North Sea as part of the EPSRC–funded CONTAIN project; underground cavern host rock (halite) for proposed underground compressed air storage as part of the EPSRC-funded IMAGES project; strength and deformability of the Montorfano Granite as part of the SAFER project; and measurement and characterisation of stress induced changes in the electric stress field of geological and man–made materials as part of the EPSRC–funded E–Stress project.

Triaxial compression specimen encased in PTFE and mounted between hardened stainless steel platens fitted with acoustic emission transducers and pore water ports.

Intact rock testing undertaken in RMPL includes:

  • Index (density, effective porosity, and water content)
  • Uniaxial compressive strength and deformability (static elastic moduli)
  • Single– and multi–stage triaxial compressive strength and deformability (static elastic moduli, Hoek–Brown and Mohr–Coulomb failure envelope calculation)
  • Indirect tensile strength of weak rocks (Brazilian Disc, FRACKiT)
  • Transient permeability in triaxial compression (moderate to high permeability specimens)
  • P– and S–wave velocity in triaxial compression (including dynamic elastic moduli)
  • Direct shear strength (portable rock shear box)
  • Point Load Strength Index
  • Schmidt Rebound Hardness Value
  • 3D swelling strain
  • Slake durability

EU funded projects:

FP7-PEOPLE-2013- Marie Curie Career Integration Grant, SAFER, 2014


Other large initiatives:

Engineering and Physical Sciences Research Council (EPSRC) projects – CONTAIN, IMAGES, E-Stress.

Partnership with University Milano-Bicocca: Investigating strength anisotropy of alpine rocks (Undergraduate, PhD and post-doctoral research).

Partnership with the University of Leicester: Investigating geomechanical properties of igneous rocks (MSci and PhD research)

Commercial laboratory testing for rock strength and deformability – Saudi Aramco, Arup, Schlumberger, Building and Construction Authority (Singapore).

Contact

Please contact Marcus Dobbs for further information.


Selected publications:

Bubeck, A, Walker, R, Healy, D, Dobbs, M, Holwell, D and Stephens, T. ¿Cómo se lava? How representative are "typical lavas" in volcanic stability models? The Geology of Geomechanics. The Geological Society, Burlington House London. 28–29 October 2015.

Bolognesi, F, Vinciguerra, S, Bistacchi, A and Dobbs, M. The Role of Phyllosilicate&rich Mylonitic Fabric on Deformation, Failure Mode and Fault Weakness: New Insights from Rock Deformation Laboratory Experiments. 11th Euroconference on Rock Physics and Rock Mechanics. 6–11 September. Ambleside, UK.

Agliardi, F, Vinciguerra, S, Dobbs, M and Zanchetta, S. Contrasting Failure Modes of Folded Gneiss Revealed by Mechanical, Microseismic and Microstructural Data. 11th Euroconference on Rock Physics and Rock Mechanics. 6–11 September. Ambleside, UK.

Archer, J, W, Dobbs, M R, Reeves, H J and Prance, R J. Measuring Stress in Rock Using Electric Potential Sensor Technology. 11th Euroconference on Rock Physics and Rock Mechanics. 6–11 September. Ambleside, UK.

Dobbs, M R, Ougier-Simonin, A, Graham, C C, Cuss, R J and Harrington, J F. CONTAIN: The Geomechanics of Candidate CCS Reservoirs and Seals. 11th Euroconference on Rock Physics and Rock Mechanics. 6–11 September. Ambleside, UK.

Castagna, A, Vinciguerra, S, De Paola, N, Nielsen, S, Benson, P, Walker, R J and Ougier-Simonin, A. Frictional and Mechanical Properties of Volcanic and Sedimentary Rocks. Application to Mt. Etna (Sicily). 11th Euroconference on Rock Physics and Rock Mechanics. 6–11 September. Ambleside, UK.

Agliardi, F, Vinciguerra, S, Dobbs, M R, Zanchetta, S. Role of folded anisotropic fabric in the failure mode of gneiss: new insights from mechanical, microseismic and microstructural laboratory data. EGU General Assembly 2015, Vienna; 04/2015.

Agliardi, F, Vinciguerra, S, Dobbs, M, Zanchetta, S. Deformation and Brittle Failure of Folded Gneiss in Triaxial Compression: Failure Modes, Acoustic Signatures and Microfabric Controls. AGU Fall meeting 2014, San Francisco, 15–19 December 2014.

Bolognesi, F, Bistacchi, A, Dobbs, M, Vinciguerra, S. How does Brittle Deformation of Phyllosilicate-rich Mylonites Work? Implications for Fault Weakness. AGU Fall meeting 2014, San Francisco, 15–19 December 2014.

Dobbs M, Archer J, Aydin A, Kirkham M, Reeves H, and Prance, R. 2014. Physical and mechanical factors affecting stress induced electric potential field in rock. 10th Euroconference on Rock Physics and Rock Mechanics. 12–15 May 2014. Aussois, France.

Bolognesi, F, Bistacchi, A, Dobbs, M, and Vinciguerra, S. The lock–up angle for brittle activation of a phyllosilicate-rich Mylonitic fabric: implications for rock strength and failure modes. 10th Euroconference on Rock Physics and Rock Mechanics. 12—15 May 2014. Aussois, France.

Agliardi, F, Vinciguerra, S, Dobbs, M, and Zanchetta, S. Deformation and failure mode of the Monte Canale micro-folded gneiss. 10th Euroconference on Rock Physics and Rock Mechanics. 12–15 May 2014. Aussois, France.

Faoro, I, Vinciguerra, S, Marone, C, Elsworth, D, and Schubnel, A. 2013. Linking permeability and mechanical damage for basalt from Mt Etna Volcano, Geophysical Research Letters, VOL. 40, 1–6, doi:10.1002/grl.50436

Aydin, A, Dobbs, M R, Reeves, H J, Kirkham, M P, Graham, C C, and Jefferson, I. 2013. Electric field in compressed concrete using the Electric Potential Sensor. Second Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures. 9–11th September 2013. Istanbul, Turkey.

Aydin, A, Dobbs, M R, Reeves, H J, Kirkham, M P, and Graham, C C. 2013. Stress induced electric field measurements of different rock lithology using the Electric Potential Sensor. 47th US Rock Mechanics/Geomechanics Symposium. 23–26th June 2013. San Francisco, USA.

Aydin, A, Dobbs, M R, Reeves, H J, Graham, C C, and Kirkham, M P. 2013. Measuring stress induced electric field in Sandstone and Granite using the Electric Potential Sensor. EUROCK 2013 21–26th September 2013. Wroclaw, Poland.

Dobbs, M R, Culshaw, M G, Northmore, K J, Reeves, H J, Entwisle, D C. 2012. Methodology for creating national engineering geological maps of the UK. Quarterly Journal of Engineering Geology and Hydrogeology, 45 (3). 335–347. 10.1144/1470–9236/12–003