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Elastic-plastic deformation of anhydrite and polyhalite as determined from quasi-static triaxial compression tests

Technical Report ·
OSTI ID:6407017

Constant stress-rate triaxial compression experiments were performed on specimens of anhydrite and polyhalite at low confining pressure and at two temperatures. The loading rate was 5.75 x 10/sup -2/ MPa s/sup -1/; the confining pressures were 1, 5, 10, and 20 MPa and the two temperatures were 25/sup 0/C and 100/sup 0/C. The specimens were loaded to failure in a soft testing machine so that failure occurred at peak stress. Results from these experiments were used to construct yield envelopes, failure envelopes and stress-strain curves, and to determine mechanical properties. Yield, determined by the onset of dilatancy, occurs at about sixty percent of peak stress. The effect of temperature on both the yield and failure envelopes is negligible. The polyhalite specimens were found to be about twice as strong as the anhydrite specimens. The stress-strain data were fitted to a constitutive law.

Research Organization:
RE/SPEC, Inc., Rapid City, SD (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
6407017
Report Number(s):
SAND-81-7063
Country of Publication:
United States
Language:
English