Elasticity of Rock in Uniaxial Strain
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF EARTH ATMOSPHERIC AND PLANETARY SCIENCES
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Deformation under conditions of uniaxial strain was found elsewhere to be very nearly recoverable for rocks like granite, diabase and certain limestones. This apparent elastic behavior is examined here in greater detail. Volumetric compression as a function of mean stress was closely predictable from our measurements of compressibility. However, Poissons ratio in uniaxial strain was up to 25 percent higher than the value the authors obtained in a direct static measurement. Motion on cracks was assumed to have occurred during uniaxial strain, and an elastic analysis was carried out based on the model of a crack-filled solid developed previously by Walsh. The theory correctly predicted characteristics of volumetric compression and Poissons ratio observed experimentally. The pressure calculated in a shock experiment for Westerly granite would be up to 30 percent higher if the appropriate Poissons ratio for uniaxial strain is used instead of the commonly tabulated value found at high hydrostatic pressure.
- Geology, Geochemistry and Mineralogy