THE EFFECTS OF SIZE AND STRESS GRADIENT ON THE STRENGTH OF ROCK

THE INFLUENCE OF THE SIZE OF SPECIMEN ON THE STRENGTH OF ROCK HAS BEEN LITTLE STUDIED THOUGH IT IS COMMONLY ASSUMED, AS HAS BEEN DEMONSTRATED FOR COAL, THAT IMPORTANT SIZE EFFECTS EXIST. MEASUREMENTS HAVE BEEN MADE OF THE UNIAXIAL COMPRESSIVE STRENGTH OF CYLINDRICAL SPECIMENS OF WITWATERSRAND SHALE AND QUARTIZITE WITH A LENGTH TO DIAMETER RATIO OF 3 TO 1 COVERING A RANGE OF DIAMETERS FROM 0.56 CM TO 15.23 CM. BEARING TESTS TO FRACTURE HAVE ALSO BEEN MADE ON SPECIMENS OF THE SAME ROCKS USING CIRCULAR METAL PUNCHES COVERING THE SAME RANGE OF DIAMETERS. THE RESULTS SHOW THAT THE STRENGTH OF THESE ROCKS IS VIRTUALLY INDEPENDENT OF SIZE UNDER THE CONDITIONS OF UNIFORM STRESS PREVAILING IN THE UNIAXIAL TESTS BUT THAT THE PUNCH BEARING STRENGTH, WHERE STRESS GRADIENTS PREVAIL, IS MARKEDLY SIZE DEPENDENT. IT IS CONCLUDED THAT STRESS GRADIENTS ARE IMPORTANT IN DETERMINING THE STRENGTH OF STRUCTURES IN ROCK EXHIBITING BRITTLE BEHAVIOR. /AUTHOR/

  • Supplemental Notes:
    • Vol 2, No 3-5, PP 31-34, 2 FIG, 12 REF
  • Authors:
    • HODGSON, K
    • Cook, N G
  • Publication Date: 1970

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Filing Info

  • Accession Number: 00236166
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 22 1972 12:00AM