DETERMINATION OF THE VIRGIN STATE OF STRESS IN THE VICINITY OF A BOREHOLE FROM MEASUREMENTS OF A PARTIAL INELASTIC STRAIN TENSOR IN DRILL CORES

A LOW-COST METHOD IS DESCRIBED FOR DETERMINING THE DIRECTIONS AND VALUES OF PRINCIPAL STRESSES FROM MEASUREMENTS MADE ON CORES OBTAINED FROM A SINGLE DEEP BOREHOLE DRILLED IN A ROCK MASS OF A GIVEN DIRECTION. EXPERIENCE SHOWS THAT PARTIAL INELASTIC DEFORMATION IS PROPORTIONAL TO THE TOTAL DEFORMATION, THEREFORE TO THE INITIAL STATE OF STRESS IN RHEOLOGICALLY ISOTROPIC ROCKS. IF CORES ARE SUBMITTED TO NON-DESTRUCTIVE TESTING AS SOON AS THEY ARE DRILLED FROM THE BOREHOLE, IT IS POSSIBLE TO DETERMINE PART OF THE TOTAL STRAIN TENSOR. ELLIPSOIDS OF STRESSES AND DEFORMATIONS, CALCULATED FROM THESE VALUES, HAVE THE SAME SHAPE AND ORIENTATION THAN THOSE WHICH EXISTED BEFORE STRESS RELEASE. RELATIONS BETWEEN THE PRINCIPAL STRESSES CAN BE CALCULATED TOGETHER WITH THEIR PRINCIPAL STRESS VALUE BY PROPORTIONALITY FROM THE ELLIPSOID OF STRESSES (1) BY USING THE SLOPES OF THE RECOVERY CURVES WHICH DEPEND ON THE STRESS, (2) BY USING THE HYPOTHESIS THAT THE PRINCIPAL STRESS IS THE STRESS RESULTING FROM THE WEIGHT OF THE COVERING AND (3) BY USING "ABSOLUTE" MEASUREMENTS OBTAINED WITH STANDARD BIAXIAL APPARATUS WHICH CAN BE UTILIZED IN CONJUNCTION WITH PARTIAL INELASTIC DEFORMATION MEASUREMENTS. /LCPC(A)/RRL/

  • Supplemental Notes:
    • Vol 6/4, pp 201-215, 4 FIG, REGS
  • Authors:
    • VOIGHT, B
  • Publication Date: 1968

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Filing Info

  • Accession Number: 00235027
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Aug 29 1971 12:00AM