A portable triaxial cell for beamline imaging of rocks under triaxial state of stress

With recent developments in direct imaging techniques using x-ray and neutron imaging, there is an increasing need for an efficient design of a test setup to study mechanical and/or the transport behaviour of porous rocks. Bespoke design from commercial suppliers are expensive and often difficult to modify. This paper presents a novel design of a portable triaxial cell for imaging deformation (and suggestion for adaptation for introducing fluid transport) through rocks/sand/soil under triaxial state of stress representative of those encountered in case of ground water aquifers or subsurface hydrocarbon reservoirs. The design philosophy and the parameters are detailed so that interested researchers can use this experimental set up as a template to design and modify the triaxial cell to suit their own experimental requirements. The design has been used on two imaging beamlines- IMAT, ISIS facility, Harwell, Oxfordshire, UK and BT2 of National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, MD, USA. The mass attenuation coefficients extracted from the 2D radiograms of the triaxial cell were compared with those reported in the literature. Further suggestions for the adaptation of triaxial cell for studying mechanics of deformation and fracture in rocks are included.