Geomechanical Testing

John Browning, BSc, MSc, PhD

EXPERIMENTAL APPARATUS DESIGN FOR CURRENT POST-DOCTORAL PROJECT

I have designed and manufactured a true triaxial loading apparatus which consists of:

60 MPa confining pressure vessel
Three sets of servo-controlled hydraulically operated actuators capable of loading up to 500 kN in three separate directions on cubic samples
Six-axis dual intensifier pore-fluid pressure system for testing water and gas permeability on jacketed samples
Installation, setup and programming of LabView software for operational control and data processing

This machine has been used for geomechanical testing of rocks in three-dimensional stress and strain fields. Data acquired will be used to understand how permeability (a fundamental property of rocks and geo-engineered materials) evolves under truly triaxial stress conditions.

Publications using these techniques:

Browning, J., Meredith, P., Stuart, C., Healy, D., Harland, S., Mitchell, T., (2017). Acoustic characterization of crack damage evolution in sandstone deformed under conventional and true triaxial loading. Journal of Geophysical Research: Solid Earth. 122, DOI 10.1002/2016JB013646

Browning, J., Meredith, P., Stuart, C., Healy, D., Harland, S., Mitchell, T., (i2018). A directional crack damage memory effect in Sandstone under true triaxial loading. Geophysical Research Letters.

Panteleev, I., Lyakhovsky, V., Browning, J., Meredith, P.G., Healy, D. and Mitchell, T.M., 2021. Non-linear anisotropic damage rheology model: Theory and experimental verification. European Journal of Mechanics-A/Solids, 85, p.104085.

LABORATORY GEOTECHNICAL CHARACTERISATION

Substantial experience of geotechnical characterization of materials using the following laboratory apparatus:

200 kN uniaxial press
1500 kN triaxial press and 150 MPa pore fluid pressure system
150 MPa hydrostatic permeameters
Helium pycnometre
Benchtop ultrasonic wave velocity measurements
High temperature furnace and acoustic emissions monitoring equipment
50 kN uniaxial press with environmental chamber

Relevant publications:

Castagna, A., Ougier-Simonin, A., Benson, P.M., Browning, J., Walker, R.J., Fazio, M., Vinciguerra, S. (2018) Damage and strain evolution in thermally treated Comiso limestone. Journal of Geophysical Research.

Daoud, A., Browning, J., Meredith, P., Mitchell, T. (2020). Mineralogical control on thermal damage and the presence of a thermal Kaiser effect during temperature-cycling experiments. Geophysical Research Letters.

Browning, J., Meredith, P., Gudmundsson, A. (2016) Cooling dominated cracking in thermally stressed volcanic rocks. Geophysical Research Letters. 43, 8417-8425.

Winnard, B., Meredith, P.G., Mitchell, T.M., Browning, J., Cuss, R., Norris, S. Evolution of bentonite permeability in response to changing salinity. Clay conference, Davos, 2017.

Harland, S., Healy, D., Cappa, F., Meredith, P., Mitchell, T., Browning, J., The influence of permeability anisotropy on effective stress and fault stability. EGU general assembly 2017, Vienna, Austria.

GEOTECHNICAL TESTING FOR INDUSTRY

Member of a Swiss Competence Center of Energy Research – Supply of Electricity (SCCCER – SOE) funded collaborative project (KG2B) to provide geotechnical characterisation of a Grimsel Granite from an underground hard rock laboratory.

David, C., Wassermann, J and the KG2B Team (2019). KG²B: a collaborative benchmarking exercise for estimating the permeability of the Grimsel granodiorite: measurements, pressure dependence and pore-fluid effects. Journal of Geophysical Research: Solid Earth

David, C., Wassermann, J and the KG2B Team (2019). KG²B, a collaborative benchmarking exercise for estimating the permeability of the Grimsel granodiorite: modeling, microstructures and complementary data. Journal of Geophysical Research: Solid Earth

Member of the KCL group run by the Universite de Clergy Pontoise designed to test Cobourg Limestone which is found at a depth of 600 m and is being considered by the Nuclear Waste Management Organisation (NWMO) for the siting of low-intermediete level nuclear waste in Canada.

Extensive characterisation and testing of materials proposed as part of engineered barriers (such as Bentonite and Granite) for the containment of nuclear waste in disposal facilities planned in the United Kingdom. Work in collaboration with the British Geological Survey and Radioactive Waste Management UK.

Winnard, B., Cuss, R., Mitchell, T., Norris, S., Browning, J., Meredith, P. Freeze-thaw effects on the microstructural properties of bentonite. Joint assembly, Liverpool, 2017.

Winnard, B., Meredith, P.G., Mitchell, T.M., Browning, J., Cuss, R., Norris, S. Evolution of bentonite permeability in response to changing salinity. Clay conference, Davos, 2017.

FIELD MAPPING AND MODELLING OF UNCONVENTIONAL HYDROCARBON RESERVOIRS

Mapping and fracture network characterisation and modelling of sills in Iceland and Northern England to assess suitability of sills to act as unconventional hydrocarbon reservoirs in the Voring Margin of Norway. Work sponsored by E.ON, E&P Norge, Repsol Exploration Norway, RWE Dea Norge and Tectonor AS.

BIAXIAL APPARATUS FOR METRE SIZE SAMPLES - APPLICATION TO BLOCK CAVING PROBLEMS

In order to understand the influence of elevated horizontal stresses on block caving processes we reconfigured an existing large-scale biaxial press in the Geotechnical Lab of PUC. Using metre size blocks of carefully characterized rock analogue materials, deformation was monitored with LVDT's and image reconstruction techniques.