FORMATION OF FAULT DAMAGE ZONES
The goal of this research is to evaluate how the state of stress and material properties of rock affect the strain-rate dependence of fragmentation (fragment size distribution, shape, etc.) and by extension fracture density. Understanding this relationship is important in understanding damage produced during earthquakes, meteorite impacts (see Meteorite Impact research page), and landslides (see Volcanic Landslide and Southern Utah Landslides research pages). I focus on creating laboratory experiments that recreate the type of fragmentation /fracture density that occurs near the surface of planetary bodies, primarily the Earth. I use different rock testing apparatuses including a Split Hopkinson Pressure Bar (fast experiments) and a triaxial apparatus (slow experiments) to study a brittle deformation under a range of strain-rates. The sample configuration used in these devices can be modified to produce different kinds of stress. I primarily focus on a modified sample configuration that consists of a rock disk bound on either side by disks consisting of materials (e.g., lead) that are more compliant (smaller Young's Modulus) and less compressible (larger Poisson's Ratio) than the inner rock disk. This sample configuration allows me to evaluate rock fragmentation under transversely isotropic tension.
OSU Structural Geology and Geomechanics Laboratory showing a Split Hopkinson Pressure Bar (foreground) and a triaxial apparatus (background).
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High-speed video of a dynamic uniaxial compression test on Westerly Granite using a Split Hopkinson Pressure Bar. Experiment conducted at the OSU Structural Geology and Geomechanics Laboratory (Link). |