Static and dynamic mechanical properties tests of core material from hole U8j at the Nevada Test Site

Conference · Mon Jan 27 04:00:00 EST 1986

OSTI ID:6015928

Anderson, G D; Kusubov, A S

Core samples were obtained from Hole U8j at the Nevada Test Site. The cores were from depths of 494 m (Fraction Ash Flow Tuff) and 427 m (Altered Bedded Tuff). Quasi-static triaxial tests were performed at a strain rate of 10/sup -4//s at confining pressures from 0.1 to 300 MPa on material that retained the in-situ integrity and water content. The failure strength, defined as the difference in principal stresses at failure, of the material from 494 m increased from 9.7 MPa to over 90 MPa while that of the material from 427 m increased from about 10 MPa to over 300 MPa, over the range of confining pressures applied. The longitudinal strains at failure ranged from 2 to 7%. Dynamic high-strain-rate tests (10/sup 4//s-10/sup 5//s) were performed on solid core samples and on wet and dry reconstituted samples of the material from 494 m depth. These tests were flat impact tests using a gas gun and magnetic particle velocity gauges to look for dynamic strength effects. The shock wave stress regime was 250 to 1270 MPa. No wave structure indicative of dynamic yielding was observed in the reconstituted samples. However, a wave structure was observed in the core material. Interpreting this wave structure as dynamic failure and using a value of Poisson's ratio from ultrasonic data to compute the transverse stress, the data suggest a dynamic failure strength of unfractured material under uniaxial strain about 35% higher than that observed quasi-statically at comparable confining pressures. The absence of dynamic yielding in reconstituted samples suggests that the lower limit dynamic failure stress for reconstituted material is below 100 MPa. 5 refs., 7 figs., 5 tabs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6015928
• Report Number(s): UCRL-92456; CONF-850953-22; ON: DE86008387
• Country of Publication: United States
• Language: English

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CAVITIES
DATA
DRILL CORES
EXPERIMENTAL DATA
FAILURES
GROWTH
HIGH PRESSURE
IMPACT TESTS
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MATERIALS TESTING
MECHANICAL PROPERTIES
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NUMERICAL DATA
SHOCK WAVES
STRAINS
STRESSES
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US DOE
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