A.V. Garcia, R.M. Rached, J.C. Santamarina
Geotechnical Testing Journal, volume 41, issue 4, (2018)
Geophysics, Rock mechanics, Hydraulic fracturing, True triaxial, Fractured rock, Jointed rock, Rock testing, Fracture network, P-wave, Load frame
The study of fractured rock masses in the laboratory remains challenging
because of the large specimen sizes and bulky loading systems that are
required. This article presents the design, structural analysis, and
operation of a compact and self-reacting true triaxial device for
fractured rock. The frame subjects a 50 cm by 50 cm by 50 cm fractured
rock specimen to a maximum stress of 3 MPa along three independent axes.
Concurrent measurements include long-wavelength P-wave propagation,
passive acoustic emission monitoring, deformations, and thermal
measurements. The device can accommodate diverse research, from rock
mass properties and geophysical fractured rock characterizations, to
coupled hydro-chemo-thermo-mechanical processes, drilling, and grouting.
Preliminary wave propagation data gathered under isotropic and
anisotropic stress conditions for an assembly of 4,000 rock blocks
demonstrate the system’s versatility and provide unprecedented
information related to long-wavelength propagation in fractured rock
under various stress anisotropies.