Tunnel and Underground Space (터널과지하공간)

Korean Society for Rock Mechanics and Rock Engineering (한국암반공학회)
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Influence of the Geometry of Guide Groove on Stress Corrosion Index of Rock in Double Torsion Test

이중 비틀림 시험에서 유도 홈의 형상이 암석의 응력부식지수에 미치는 영향

  • 정해식 (서울대학교 지구환경시스템공학부) ;
  • 미원우삼 (일본 구마모토대학 환경시스템공학과) ;
  • 전석원 (서울대학교 지구환경시스템공학부)
  • Published : 2004.10.01
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Abstract

Double torsion (DT) tests were carried out to investigate the influence of the geometry of guide groove on stress corrosion index of Kumamoto andesite. The fracture toughness was measured in the constant displacement rate, which was set to 2.07 MN/m$^{3}$2/ in average regardless of crack velocity. Stress corrosion indices, n were evaluated using specimens with rectangular, circular and triangular grooves and were 37, 36 and 38 in average, respectively. The n values were constant regardless of the groove geometry, however the DT specimen with triangular groove geometry showed the largest standard deviation in the relationship between crack velocity and stress intensity factor. The DT test was found to be effective in using a rectangular-grooved specimen and the width of the groove must be greater than the average grain size of minerals.

구마모토 안산암을 대상으로 이중 비틀림(DT) 시험을 통해 유도 홈의 단면 형상이 암석의 응력부식지수에 미치는 영향에 대하여 조사하였다. 정변위속도법에서 변위속도가 증가할수록 균열성장속도는 증가하지만 파괴인성계수는 평균 2.07 MN/m$^{3}$2/로 거의 일정하였다. 정변위법을 통하여 유도 홈의 형상이 사각형, 원형, 삼각형인 시험편을 이용하여 얻은 응력부식지수는 각각 평균 37, 36, 38로 홈의 형상에 관계없이 거의 일정한 값을 보이지만 표준편차는 삼각형 홈에서 가장 크게 나타났다. 암석의 DT시험은 중앙부에 유도 홈이 있는 시험편을 이용하는 것이 효과적이지만 광물의 평균입경 이상의 폭을 가진 사각형 단면의 홈을 이용하는 것이 가장 적절하다.

Keywords

References

  1. Anderson, O.L. and P.C. Grew, 1977, Stress corrosion theory of crack propagation with applications to geophysics, Rev. Geophys. Space Phys., 15, 77-104 https://doi.org/10.1029/RG015i001p00077
  2. Atkinson, B.K. and P.G. Meredith, 1987, The theory of subcritical crack growth with applications to minerals and rocks, in Fracture Mechanics of Rock, edited by Atkinson, B. K., Academic press, London, 111-166
  3. Bruce J.G. and B.G. Koepke, 1977, Evaluation of $K_{IC}$ by the double-torsion technique, J. Am. Ceram. Soc., 60, 284-285 https://doi.org/10.1111/j.1151-2916.1977.tb14131.x
  4. Evans, A.G., 1972, A method for evaluating the time dependent failure characteristics of brittle materials and its application to ploycrystalline alumina, J. Mater. Sci., 7, 1137-1146 https://doi.org/10.1007/BF00550196
  5. Evans, A.G. and H. Johnson, 1975, The fracture stress and its dependence on slow crack growth, J. Mater. Sci., 10, 214-222 https://doi.org/10.1007/BF00540345
  6. Fuller Jr., E.R., 1979, An evaluation of double-torsion testing : Analysis, ASTM STP, 678, 3-18
  7. Jeong, H.S. and Y. Obara, 2002, Strength of Kumamoto andesite in non-atmospheric environments, Shigen-to-Sozai, 118, 599-604(in Japanese) https://doi.org/10.2473/shigentosozai.118.599
  8. Michalske, T.A. and S.W. Freiman, 1982, A molecular interpretation of stress corrosion in silica, Nature, 295, 511-512 https://doi.org/10.1038/295511a0
  9. Obara, Y., K. Sakaguchi, T. Nakayama and K. Sugawara, 1992, Anisotropy effect on fracture toughness of rock, Proc. ISRM Symposium, Eurock '92, Telford, T., London, 7-12
  10. Pabst R.F. and J. Weick, 1981, Double-torsion measurements with and without a guiding notch, J. Mater. Sci., 16, 836-838 https://doi.org/10.1007/BF02402805
  11. Pletka, B.J., E.R. Fuller and B.G. Koepke, 1979, An evaluation of double-torsion testing experimental, ASTM STP, 678, 19-37
  12. Sano, O., 1988, A revision of the double-torsion technique for brittle materials, J. Mater. Sci., 23, 2505-2511 https://doi.org/10.1007/BF01111909
  13. Speidel, M.O., 1971, Current understanding of stress corrosion crack growth in aluminum alloys, In: The theory of stress corrosion cracking in alloys, ed. Scully, J.C., North Atlantic Treaty Organization, Brussels, 289-344
  14. Trantina, G.G., 1977, Stress analysis of the double-torsion specimen, J. Am. Ceram. Soc., 60, 338-341 https://doi.org/10.1111/j.1151-2916.1977.tb15556.x
  15. Wakai, F., H. Sakuramoto, S. Sakaguchi and Y. Matsuno, 1986, Evaluation of crack propagation in ceramics by double-torsion, Zairyo, 35, 898-903 (in Japanese)
  16. Williams, D.P. and A.G. Evans, 1973, A simple method for studying slow crack growth, J. Test. Eval., 1, 264-270 https://doi.org/10.1520/JTE10015J