Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Compressibility and Stiffness Characteristics of Vanishing Mixtures

지반 소실 혼합재의 압축성 및 강성 특성

  • Truong, Q. Hung (Dept. of Civil, Environmental, and Architectural Engrg., Korea Univ.) ;
  • Eom, Yong-Hun (Dept. of Civil, Environmental, and Architectural Engrg., Korea Univ.) ;
  • Yoon, Hyung-Koo (Dept. of Civil, Environmental, and Architectural Engrg., Korea Univ.) ;
  • Lee, Jong-Sub (Dept. of Civil, Environmental, and Architectural Engrg., Korea Univ.)
  • 쭝꽝훙 (고려대학교 건축.사회환경공학과) ;
  • 엄용훈 (고려대학교 건축.사회환경공학과) ;
  • 윤형구 (고려대학교 건축.사회환경공학과) ;
  • 이종섭 (고려대학교 건축.사회환경공학과)
  • Published : 2008.12.31
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Abstract

Soils naturally contain grains of different minerals which may be dissolved under chemical or physical processes. The dissolution leads changes in microstructure of particulate media, such as an increase in local void or permeability, which affects the strength and deformation of soils. This study focuses on the small strain stiffness characteristics of vanishing mixtures, which consist of sand and salt particles at different volume fractions. Experiments are carried out in a conventional oedometer cell (Ko-loading) integrated with bender elements for the measurement of shear waves. Dissolutions of particles are implemented by saturating the mixtures at various confining stresses. Axial deformation and shear waves are recorded after each loading stage and during dissolution process. Experimental results show that after dissolution, the vertical strain and the void ratio increase, while the shear wave velocity and small strain shear modulus decrease. The decrease of the velocity results from the void ratio increase and particle contact decrease. The process monitoring during dissolution of the particles shows that the vertical strain dramatically increases at the beginning of the saturation process and converges after vanishing process finishes, and that the shear wave velocity decreases at the beginning and increases due to the particle reorientation. Specimens prepared by sand and salt particles are proved to be able to provide a valuable insight in macro structural behaviors of the vanishings mixtures.

지반은 화학적 및 물리적인 작용으로 인하여 지반 자체가 용해되어 지반 재료 자체가 자연적으로 소실(Vanishing)되는 입자를 포함하고 있다. 지반의 소실은 입자로 구성된 재질에서 국부적인 간극 및 투수계수의 증가와 같은 미소구조의 변화를 유발하여 지반의 강도와 변형에 영향을 미친다. 본 논문에서는 지반 재료의 소실 발생 시 대상지반의 국부적인 강성의 변화특성을 파악하기 위하여 소금과 모래를 여러 가지 부피비로 혼합하여 사용하였다. 실험은 전단파 측정을 위한 벤더 엘리먼트가 설치된 압밀셀을 이용하여 수행하였다. 입자의 용해는 다양한 구속응력 하에서 시료를 포화시켜 수행하였다. 축방향 변형률과 전단파 신호를 매 하중 단계와 입자용해 시 측정하였다. 실험 결과, 입자 용해 후 축방향변형률과 간극비는 증가하였고, 전단파 속도와 최대전단탄성계수는 감소하는 것으로 나타났다. 입자 용해로 인한 간극비 증가와 입자간의 접촉이 감소하여 전단파 속도가 감소하였다. 입자가 용해되는 동안 수직변형률은 포화 시작점에서 급격히 증가하였으며 입자 용해가 완료되면서 수렴하였으며, 전 단파속도는 시작 시 감소하였다가 입자가 재배열되면서 증가하는 것으로 나타났다. 모래와 소금으로 구성된 시료는 지반소실재의 거시적 구조 거동에 의미있는 결과를 보여줄 수 있는 것으로 나타났다.

Keywords

References

  1. Azam, S, (2000), 'Collapse and comprcssibilily behaviour of arid calcareous soil fomations', Bulletin of Engineering Geology and the Environment, Springer Berlin, 59(3), pp.211-217 https://doi.org/10.1007/s100640000060
  2. Bell. F. G. (2004), Engineerillg Gealogy-2nd edition. Elsevier. Great Britain
  3. Blyth, F.G.H. and de Freitas, M. H. (1984), A Geology for Engineers. Elsevicr Butterworth. Oxford
  4. Craft, D., Cain, C. and Sullivan. C. (2006), 'Seepage Geochemistry and Mineral Dissolution at Clark Canyon Dam, Pick-Sloan Missouri Basin Project, East Bench Unit, Montana,' Technical Memorandum 86-6829010, U.S. Department of the Interior - Bureau of Reclamation, Denver, Colorado, p.48
  5. Craft, D. (2005), 'Seepage Chemistry Manual', Report DSO-05-03, US Departent of the Interior, Bureau of Reclamation, Dam Safety Technology Development Program, Denver. Colorado. p.76
  6. Fam, M. A., Cascante, G., and Dusseault, M. B. (2002), 'Large and Small Strain Properties of Sands Subjected to Local Void Increase', Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 128(12), pp.1018-1025 https://doi.org/10.1061/(ASCE)1090-0241(2002)128:12(1018)
  7. Fam, M. A. and Santamarina, J. C. (1995), 'Study of geoprocesses with complementary wavc measurements in an oedometer', Geotechnical Testing Journal, ASTM. 18(3), 307-314 https://doi.org/10.1520/GTJ10999J
  8. Hillel, D. (2004), 'Encyclopedia of Soils in the Environment', Academic Press, Volume I
  9. Hardin, B. O., and Drnevich, V. P. (1972), 'Shear modulus and damping in soils: Measurement and parameter effects', Soil Mechenics and Foundation Division, ASCE, 98 (6), pp.603-624
  10. Jeremic, M. J. ( 1994), Rock Mechanics in Salt Mining. Balkema, Rotterdam
  11. Lee, J. S. and Santamarina, J. C. (2005), 'Bender elements: performance and signal interpretation', Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 131(9), pp.1063-1070 https://doi.org/10.1061/(ASCE)1090-0241(2005)131:9(1063)
  12. Lee, J.S., and Santamarina, J.C.(2007), 'Seismic monitoring short-duralion vents Liqucfaction in lg models', Canadian Geotechnical Journal, 44(6), pp.659-672 https://doi.org/10.1139/T07-020
  13. Lee, J.S., Guimaraes, M., and Santamarina. J. C. (2007-a), 'Micaceous sand: Fabric, stiffness, and strength', Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 133(9), pp.1136-1143 https://doi.org/10.1061/(ASCE)1090-0241(2007)133:9(1136)
  14. Lee, J.S., Dodds, J., and Santamarina, J.C. (2007-b), 'Behavior of rigid-soft particle mixtures'. Journal of Materials in Civil Engineering, ASCE, 19(2), pp.179-184 https://doi.org/10.1061/(ASCE)0899-1561(2007)19:2(179)
  15. Santamarina, J. C., Klein, K. A., and Fam, M. A. (2001), Soils and Waves - Particulate Materials Behavior, Characterization and Process Monitoring, JohnWiley and Sons. New York
  16. Yun. T.S. Jnd Santamarina, J.C. (2005). 'Decementation, softening and collapes: Changes in small-stain shear stiffness in Ko-loading', Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 131(3), pp.350-358 https://doi.org/10.1061/(ASCE)1090-0241(2005)131:3(350)