Interrelation of flow or fracture and phase transition in the deformation of carbonate rock
Shock wave, ultrasonic, hydrostatic, and triaxial compression data for carbonate rock are considered in terms of the mechanisms of yielding. The results suggest that yielding by flow or fracture can be replaced by phase transformation for selected stress paths. For certain calcite rocks, these stress paths include uniaxial strain loading. The results further suggest that when initial yielding is by flow or fracture, behavior is strain rate dependent. This is apparently the case for Vermont marble and Blair dolomite, as comparison of the dynamic and quasi-static stress-strain paths and yield stress under uniaxial-strain loading indicates. In contrast, similar comparisons for Solenhofen limestone and Oakhall limestone show little rate dependence, suggesting that the apparent initial yielding is dominate by onset of the calcite I-II phase transition. Both static and dynamic studies show that the I-II transition in calcite rock is largely rate independent, reversible, continuous (gradual), and shear stress sensitive. Rate indepdencence and reversibility are apparently the consequence of displacive and coherent phase transformation. Continuous transformation appears to be due to rock microstructure which leads to stress concentrations and hence a spread in the macroscopic stress region over which the transition occurs. Shear stress sensitivuty can be due to both microscopic dependence of the transition on local shearing stresses and shear stress dependence of the microstructural stress injomogeneities.
- Research Organization:
- Sandia Laboratories, Albuquerque, New Mexico 87185
- OSTI ID:
- 5556673
- Journal Information:
- J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 84:B13; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
ALKALINE EARTH METAL COMPOUNDS
CARBON COMPOUNDS
CARBONATE ROCKS
CARBONATES
COMPRESSION
CRYSTAL STRUCTURE
DEFORMATION
DOLOMITE
FAILURES
FRACTURES
LIMESTONE
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MARBLE
METAMORPHIC ROCKS
MICROSTRUCTURE
MINERALS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RESERVOIR ROCK
ROCK MECHANICS
ROCKS
SEDIMENTARY ROCKS
STRESSES