THE FAILURE OF ROCK

AN ANALYSIS OF THE ENERGY CHANGES ASSOCIATED WITH THE EXTENSION OF GRIFFITH CRACKS IN TENSION AND COMPRESSION /IN HARD ROCK/ IS MADE, WHICH SHOWS THAT THE NONELASTIC BEHAVIOR CAN BE DESCRIBED BY A CURVED GRIFFITH LOCUS IN THE STRAIN- STRESS PLANE. ONLY WHEN THE SLOPE OF THIS LOCUS IS GREATER THAN 0 IS A MATERIAL INTRINSICALLY BRITTLE AND LIABLE TO SPONTANEOUS FRACTURE. WHEN THE LOCUS IS LESS 0, CRACK EXTENSION CAN PROCEED BY UNSTABLE FRACTURE OR STABLE FAILURE , DEPENDING UPON THE AMOUNT OF ENERGY SUPPLIED TO THE MATERIAL BY THE LOADING SYSTEM. THE EFFECT OF TRIAXIAL CONFINEMENT IS TO REDUCE THE NEGATIVE SLOPE OF THE GRIFFITH LOCUS AND MAKE THE MATERIAL MORE DUCTILE THAN IT IS IN UNIAXIAL COMPRESSION. MICRO-SEISMIC ACTIVITY DURING THE TESTING OF ROCK SPECIMENS CAN BE ACCOUNTED FOR BY ASSUMING THAT ROCK IS A HETEROGENEOUS MATERIAL CONTAINING ELASTIC INCLUSIONS, AND ANALYZING THE FRACTURE OF THESE INCLUSIONS IN TERMS OF THE ABOVE. EXPERIMENTAL DATA OBTAINED FROM UNIAXIAL COMPRESSION TESTS ON TENNESSEE MARBLE AND ST. CLOUD GRANITE ARE PRESENTED AND ARE SHOWN TO BE IN ACCORD WITH THE ANALYTICAL PREDICTIONS. /AUTHOR/

  • Availability:
  • Supplemental Notes:
    • Vol. 2, No 4, PP 389-403
  • Authors:
    • Cook, N G
  • Publication Date: 1965

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  • Accession Number: 00234054
  • Record Type: Publication
  • Source Agency: Geophysical Abstracts
  • Files: TRIS
  • Created Date: Jun 5 1994 12:00AM