STATIC DETERMINATION OF THE EQUATION-OF-STATE OF CEDAR CITY TONALITE.
BATTELLE MEMORIAL INST COLUMBUS OHIO COLUMBUS LABS
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Static compressibility measurements were made on samples of Cedar City tonalite of nominal densities of 2.37, 2.54, and 2.61 gcc. The purpose of these measurements was to provide equation-of-state data for code calculations. Water-saturated and dry samples were cycled to 0-12-0-24-0-38-0 kb in a piston-cylinder solid pressure media apparatus. The effect of cycling the dry samples caused the denser samples to expand on cycling the low density sample showed a large, permanent negative strain after the 0-12 kb cycle. Further crack closure on cycling was elastic. At 40 kb the samples were approaching a density which suggested all the cracks and pores had been removed. The saturated samples behaved much differently than the dry samples. Their delta V was less, their hystersis was less and their compressibility curves reproduced on cycling. Hydrostatic cycling experiments were made to 9 kb using axially and circumferentially mounted strain gages on copper-jacketed rock cylinders. The rocks showed permanent set to pressures of 1 kb. Above 1 kb the cracks and pores appeared to be removed elastically. With a few notable exceptions, the linear compressibilities of all the samples were within 10 percent of each other. Thus, with these exceptions and the exclusion of the lower density 2.37 gcc material, the rock seems generally homogenous and isotropic elastically. Author
- Geology, Geochemistry and Mineralogy
- Soil Mechanics