A NOTE ON THE FRACTURE OF ROCK UNDER IMPULSES

IN ROCK BREAKING OPERATIONS A PARTICULAR TYPE OF FRACTURE IS OFTEN REQUIRED, THIS BEING CAUSED IN MOST CASES BY IMPULSE LOADING. THE RECENT INTRODUCTION OF THE HOPKINSON SPLIT BAR METHOD READILY ENABLES THE STUDY OF FRACTURING SPECIMENS UP TO TOTAL DISINTEGRATION. IT HAS BEEN SHOWN PREVIOUSLY THAT THERE EXISTS A LIMIT TO THE ENERGY WHICH CAN BE CARRIED BY A GIVEN PULSE THROUGH ROCK. THIS LIMIT IS ESSENTIALLY A STRESS AMPLITUDE LIMIT CORRESPONDING TO THE FRACTURE INITIATION STRESS. IN THE PRESENT WORK, SHALE SPECIMENS TAKEN PARALLEL AND PERPENDICULAR TO THE BEDDING WERE TESTED AND THE TYPE OF FRACTURE UNDER VARIOUS PULSE AMPLITUDES WAS OBSERVED. THE LOWER AMPLITUDE PULSE CAUSED A BETTER SPLITTING TYPE OF FRACTURE ALONG THE BEDDING PLANES THAN THE HIGHER AMPLITUDE PULSE, WHICH SUPPORTS THE CONCLUSION, THAT IF A SPLITTING TYPE OF FRACTURE IS DESIRED IT IS BETTER TO INCREASE THE DURATION OF THE PULSE RATHER THAN THE AMPLITUDE.

  • Supplemental Notes:
    • Vol 2, No 3-32, PP 223-226, 1 TAB, 3 PHOT, 5 REF
  • Authors:
    • Hakalehto, K O
  • Publication Date: 1970

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Filing Info

  • Accession Number: 00236182
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 22 1972 12:00AM