Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
권호 표지
DOI QR코드

DOI QR Code

The Thickness of Shear Zone in Granular Materials Using Digital Image Processing

DIP 기법을 이용한 조립토의 전단영역 크기 분석

  • Min, Tuk-Ki (Dept. of Civil and Environmental Engrg., Univ. of Ulsan) ;
  • Kim, Chi-Young (Dongil Engrg. Consultants Co., Ltd.)
  • 민덕기 (울산대학교 건설환경공학부) ;
  • 김치영 (울산대학교 공과대학 건설환경공학부)
  • Published : 2006.08.01
Download PDF
⟨ Previous Next ⟩

Abstract

This study investigated the effect of relative density on the thickness of shear zone. Digital image processing was used to measure the thickness of shear zone under plane strain conditions. A suitable epoxy resin was injected into the sample and the thickness of the shear zone was investigated. Four independent condition samples were prepared and the thickness of the shear zone was measured. The results indicated that the thickness of shear zone increases as the initial density of sample increases, and during the shear, the void ratios of the shear zone were changed, but the thickness of shear zone was not changed. In addition, the result of measurement of the thickness showed that the thickness of shear zone was almost fixed before critical state, but beyond critical state, the thickness of shear zone sharply increases as relative density increases.

본 논문은 DIP(digital image processing)기법을 이용하여 조립토의 직접전단실험시 발생하는 전단영역의 크기에 대해 상대밀도와 전단하중이 미치는 영향에 대해 분석하였다. 전단변형 후 DIP기법을 적용하여 전단영역의 측정을 위해 적절한 고화제(epoxy resin)를 선택하여 4단계의 초기 상대밀도를 가진 시편이 준비되었고, 각각의 시료에 대해 전단시험 및 고화제 주입, 시편제작, 이미지 분석 등의 단계를 거쳐 전단영역의 크기가 측정하였다. 전단영역의 크기 측정 결과, 시료의 초기 삿대밀도가 증가할수록 전단영역의 크기도 증가하고, 전단하중 재하 중 전단영역 내부의 간극비는 변하지만 전단영역의 크기는 변하지 않는 것을 확인할 수 있었다. 또한, 시편의 초기 상대밀도가 한계상태 이전에는 상대밀도에 따라 전단영역의 크기가 거의 변하지 않으나 한계상태를 지나 조밀한 상태가 된 경우 상대밀도가 증가함에 따라 전단영역의 크기가 크게 증가하는 것으로 나타났다.

Keywords

References

  1. Alshibli, K. A. and Strure, S. (1999), 'Sand shear zone thickness measurements by digital imaging techniques', Journal of Computing in Civil Engineering, Vol.13, No.2, pp.103-109 https://doi.org/10.1061/(ASCE)0887-3801(1999)13:2(103)
  2. Bardet, J. P. and Proubet, J. (1991), 'A numerical investigation of the structure of persistent shear zones in granular media.', Geotechnique, Vol.41, No.4, pp.599-613 https://doi.org/10.1680/geot.1991.41.4.599
  3. Bhatia, S. K. and Soliman, A. F. (1990), 'Frequency distribution of void ratio of granular material determined by an image analyzer', Soils and Foundations, Vol.30, No.1, pp.1-16
  4. Frost, J. D. and Kuo, C. Y. (1996, a), 'Automated determination of the distribution of local void ratio from digital images', Geotechnical Testing Journal, ASTM, Vol.19, No.2, pp.107-117 https://doi.org/10.1520/GTJ10334J
  5. Frost, J. D. and Kuo, C. Y. (1996, b), 'Uniformity evaluation of cohesionless specimens using digital image analysis', Journal of Geotechnical Engineering, ASCE, Vol.122, No.5, pp. 390-396 https://doi.org/10.1061/(ASCE)0733-9410(1996)122:5(390)
  6. Matsuoka, H. (1974), 'A microscopic study on shear mechanism of granular materials', Soils and Foundations, Vol.14, No.1, pp.29-43 https://doi.org/10.3208/sandf1972.14.29
  7. Muhlhaus, H. B. and Vardoulakis, I. (1987), 'The thickness of shear zones in granular materials', Geotechnique, Vol.37, No.3, pp.271-283 https://doi.org/10.1680/geot.1987.37.3.271
  8. Oda, M. (1972, a), 'Deformation mechanism of sand in triaxial compression tests', Soils and Foundations, Vol.12, No.4, pp.45-63 https://doi.org/10.3208/sandf1972.12.4_45
  9. Oda, M. ( 1972, b), 'Initial fabrics and their relations to mechanical properties of granular material', Soils and Foundations, Vol.12, No.1, pp.17-36 https://doi.org/10.3208/sandf1960.12.17
  10. Oda, M, Kazama, H. and Konishi, J. (1998), 'Effects of induced anisotropy on the development of shear zones in granular materials', Mechanics of Materials, Elsevier, Vol.28, pp.103-111 https://doi.org/10.1016/S0167-6636(97)00018-5
  11. Scarpelli, G. and Wood, D. M. (1982), 'Experimental observations of shear zone patterns in direct shear tests', Proc. IUTAM Conf Deformation and Failure of Granular Materials, pp.473-484
  12. Sid-Ahmed, M. A. (1995), Image Processing Theory, Algorithms and Architectures, McGraw Hill, New York, 611 pp
  13. Yoshida, T., Taysuoka, F., Siddiquee, M. S. A. and Kamegai, Y. (1994), 'Shear banding in sands observed in plane strain compression', Proc. 3rd Int. Workshop on Localization and Bifurcation Theory for Soils and Rocks, (eds Chambon, R., Desrues, J. and Vardonlakis, I.) Rotterdam, Balkema, pp.165-180
  14. Image-Pro${\cicledR}$ Plus Version 4.5.1. (2002), User's Manual, Media Cybernetics, Inc