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수축 균열 발달 과정을 위한 단순 모델

A Simple Model of Shrinkage Cracking Development for Kaolinite

  • Min, Tuk-Ki (Dept. of Civil & Engiron. Engrg., Univ. of Ulsan) ;
  • Nhat, Vo Dai (Dept. of Civil & Engiron. Engrg., Univ. of Ulsan)
  • 발행 : 2007.09.30

초록

본 연구에서는 카올린점토에 대한 실내실험을 통하여 수축으로 인한 균열발생을 조사하고 균열 단계를 모사할 수 있는 단순모델을 제안하였다. CPS 기법을 이용하여 디지털 카메라에 의해 얻은 균열 이미지를 분석하였다. 함수비의 감소에 따라 균열의 길이와 면적은 1차 균열단계, 2차 균열단계, 수축단계 균열의 3단계로 나타났다. 균열 면적의 1차 및 2차 균열 최종 단계에서의 정규화된 함수비는 시료 두께에 상관없이 각각 0.92와 0.70에서 발생하였다. 반면 균열 길이는 1차 균열 최종 단계에서의 함수비는 시료 두께와 상관없이 0.92에서 발생하였으나, 2차 균열 최종 단계에서의 함수비는 시료 두께가 0.5, 1.0, 2.0cm로 증가함에 따라 함수비는 0.79, 0.82, 0.85로 증가하였다. 수축 균열을 모사할 수 있는 3개의 직선으로 구성된 단순모델을 제안하였다.

The experiments have been conducted on Kaolinite in laboratory to investigate the development of shrinkage cracking and propose a simple model. Image analysis method consisting of control point selection(CPS) technique is used to process and analyze images of soil cracking captured by a digital camera. The distributions of crack length increment and crack area increment vary as a three-step process. These steps are regarded as stages of soil cracking. They are in turn primary crack, secondary crack and shrinkage crack stages. In case of crack area, the primary and secondary stages end at normalized gravimetric water content(NGWC) of 0.92 and 0.70 for different specimen thicknesses respectively. In addition, the primary stage in case of crack length also ends at NGWC of 0.92 while the secondary stage stops at NGWC of 0.79, 0.82, and 0.85 for the sample thicknesses of 0.5, 1.0, and 2.0 cm respectively Based on the experimental results, the distributions of crack length increment and crack area increment appear to be linear with a decrease of NGWC. Therefore, the development of shrinkage cracking is proposed typically by a simple model functioned by a combination of three linear expressions.

키워드

참고문헌

  1. Albrecht, B. A. and Benson, C. H. (2001), 'Effect of Desiccation on Compacted Natural Clays', Journal of Geotechnical and Geoenvironmental Engineering, Vol.127, No.1, pp.67-75 https://doi.org/10.1061/(ASCE)1090-0241(2001)127:1(67)
  2. Homand, F., Hoxha, D., Belem, T., Pons, M-N. and Hoteit, N. (2000), 'Geometric Analysis of Damaged Microcracking in Granites', Mechanics and Materials, Vol.32, Issue.6, pp.361-376 https://doi.org/10.1016/S0167-6636(00)00005-3
  3. Hu, L. B., Peron, H., Hueckel, T. and Laloui, L. (2006), 'Numerical and Phenomenological Study of Desiccation of Soil', Advances in Unsaturated Soil, Seepage, and Environmental Geotechnics (GSP 148), Proceedings of Sessions of GeoShanghai 2006, pp.166-173
  4. Karmakar, S., Kushwaha, R.L. and Stilling, D. S. D. (2005), 'Soil Failure Associated with Crack Propagation for an Agricultural Tillage Tool', Soil and Tillage Research, Vol.84, Issue.2, pp.119-126 https://doi.org/10.1016/j.still.2004.10.005
  5. Kodikara, J. K,. Barbour, S. L. and Fredlund, D. G. (2000), 'Desiccation Cracking of Soil Layers', Unsaturated Soils for Asia, Rahardjo, Toll & Leong (eds). Balkema, Rotterdam, ISBN 90 5809 139 2, pp.693-698
  6. Konrad, J.-M. and Ayad, R. (1997), 'Desiccation of a Sensitive Clay: Field Experimental Observations', Canadian Geotechnical Journal, Vol.34, No.6, pp.929-942 https://doi.org/10.1139/cgj-34-6-929
  7. Morris, P. H., Graham, J. and Williams, D. J. (1993), 'Cracking in Drying Soils', International Journal of Rock Mechanics and Mining Science & Geomechanics Abstracts, Vol.30, No.2, pp.263 -277
  8. Peng, X, Hom, R., Peth, S. and Smucker, A. (2006), 'Quantification of Soil Shrinkage in 2D by Digital Image Processing of Soil Surface', Soil & Tillage Research, Vol.91, Issues.1-2, pp.173-180 https://doi.org/10.1016/j.still.2005.12.012
  9. Preston, S., Wirth, S., Ritz, K., Griffiths, B. S. and Young, I. M. (2001), 'The Role Played by Microorganisms in The Biogenesis of Soil Cracks: Importance of Substrate Quantity and Quality', Soil Biology and Biochemistry, Vol.33, Issues.12-13, pp.1851-1858
  10. Yelde, B. (1999), 'Structure of Surface Cracks in Soil and Muds', Geoderma, Vol.93, Issues.1-2, pp.101-124 https://doi.org/10.1016/S0016-7061(99)00047-6
  11. Yelde, B. (2001), 'Surface Cracking and Aggregate Formation Observed in a Rendzina Soil, La Touche (Yienne) France', Geoderma, Vol.99, Issues.3-4, pp.261-276 https://doi.org/10.1016/S0016-7061(00)00074-4
  12. Yogel, H.-J., Hoffmann, H. and Roth, K. (2005), 'Studies of Crack Dynamics in Clay Soil I. Experimental Methods, Results, and Morphological Quantification', Geoderma, Vol.125, Issues.3-4, pp.203 -211 https://doi.org/10.1016/j.geoderma.2004.07.009
  13. Waller, P. M. and Wallender, W. W. (1993), 'Changes in Cracking, Water Content, and Bulk Density of Salinized Swelling Clay Field Soils', Soil Science, Vol.156, No.6, pp414-423 https://doi.org/10.1097/00010694-199312000-00006
  14. Weinberger, R. (1999), 'Initiation and Growth of Cracks during Desiccation of Stratified Muddy Sediments', Journal of Structural Geology, Vol.21, Issue.4, pp.379-386 https://doi.org/10.1016/S0191-8141(99)00029-2
  15. Wijeyesekera, D. C. and Papadopoulou, M. C. (2001), 'Cracking in Clays with an Image Analysis Perspective', Clay Science for Engineering, Adachi & Fukue (eds) Balkema, Rotterdam, ISBN 90 5809 175 9, pp437-482
  16. Yesiller, N., Miller, C. J., Inci, G. and Yaldo, K. (2000), 'Desiccation and Cracking Behavior of Three Compacted Landfill Liner Soils', Engineering Geology, Vol.57, Issues. 1-2, pp.105-121 https://doi.org/10.1016/S0013-7952(00)00022-3