Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
권호 표지
DOI QR코드

DOI QR Code

Leaching Characteristics on Clay Ground induced by Artesian Pressure

피압에 의한 점토 지반의 용탈 특성

  • Yun, Daeho (Department of Ocean engineering, Pukyong National University) ;
  • Kim, Yuntae (Department of Ocean engineering, Pukyong National University)
  • Received : 2016.11.07
  • Accepted : 2016.12.25
  • Published : 2016.12.30
Download PDF
⟨ Previous Next ⟩

Abstract

This paper performed consolidation tests on soft ground with and without artesian pressure conditions to find out characteristics of leaching effects using two types of one-dimensional column equipment(height : 1,100mm, outer diameter : 250mm). Artesian pressure of 5.5kPa was applied to the bottom of soft ground inside column equipment. Distribution of salinity and shear strength with soil depth were measured after the consolidation test. From the results, it was found that distribution of undrained shear strength and salt concentrations were similar at the top of clay ground irrespective of artesian pressure condition. However, at the bottom of clay ground, the values of undrained shear strength and salt concentration under artesian pressure were lower than those without artesian pressure. This result indicates that structure of soft soil with artesian pressure was weakened by salt leaching. Electronic resistance results showed that void ratio under artesian pressure condition was more reduced than that without artesian pressure condition.

본 연구에서는 피압의 작용에 따른 점토 지반의 용탈 특성을 조사하기 위해 두 종류의 원통형 일차원 대형 컬럼 장치(높이 : 1,100mm, 직경 250mm)를 제작하여 점토 지반의 압밀 거동 실험을 수행하였다. 피압의 크기는 5.5kPa로 하부지반에서부터 작용하도록 하였으며, 압밀 실험 종료 후 점토층의 깊이에 따른 염분의 농도와 비배수 전단강도를 측정하였다. 실험 결과 비배수 전단강도 및 염분 분포는 점토층 하부에서 뚜렷한 차이를 보였으며, 상부로 갈수록 유사한 경향을 보였다. 이는 피압이 작용할 경우 점토층 내에 용탈현상이 발생하여 지반이 구조적으로 취약해져 나타난 결과로 판단된다. 또한 전기전도도 측정을 통해 시간에 따른 간극비 변화를 살펴본 결과, 피압이 작용하는 지반에서 간극율 변화가 더 크게 나타났다.

Keywords

References

  1. Archie, G. E. (1942), The electrical resistance log as an aid in determining some reservoir characteristics, Transactions of the American Institute of Mining, Metallurgical, and Petroleum Engineers, Vol.146, No.1, pp.54-62.
  2. Baek, S. H. (2002), Characterisation and Geotechnical Properties of Pusan Clays by Insitu Tests, PhD's thesis, pp.1-165(in Korean).
  3. Bjerrum, L. (1967), Engineering geology of Norwegian normally-consolidated marine clays as related to settlements of buildings, Geotechnique, Vol.17, No.2, pp.83-118. https://doi.org/10.1680/geot.1967.17.2.83
  4. Campanella, R. and Weemees, I. (1990), Development and use of an electrical resistivity cone for groundwater contamination studies, Canadian Geotechnical Journal, Vol.27, No.5, pp.557-567. https://doi.org/10.1139/t90-071
  5. Chung, S. G., Giao, P. H., Nagaraj, T. S. and Kwag, J. M. (2002), Characterization of Estuarine Marine Clays for Coastal Reclamation in Pusan, Korea, Marine Georesources and Geotechnology, Vol.20, No.4, pp.237-254. https://doi.org/10.1080/03608860290051930
  6. Han, Y. C. and Yu, G. Y. (1999), A Study of Artesian Characteristics in Yangsan/Mulgeum Site, KGS Fall '99 National Conference, pp.123-130 (in Korean).
  7. He, P., Ohtsubo, M., Abe, H., Higashi, T. and Kanayama, M. (2014), Quick Clay Development and Cation Composition of Pore Water in Marine Sediments from the Ariake Bay Area, Japan, International Journal of Geosciences, Vol.5, No.6, pp.595-606. https://doi.org/10.4236/ijg.2014.56054
  8. Heo, D. Y. (2003), A Study on the Depositional Environment and Geotechnical Properties of Clay Deposited at the Busan New Port Site, Dong-A University, PhD's thesis, pp.8-198 (in Korean).
  9. Jackson, P., Smith, D. T. and Stanford, P. (1978), Resistivityporosityparticle shape relationships for marine sands, Geophysics, Vol.43, No.6, pp.1250-1268. https://doi.org/10.1190/1.1440891
  10. Kim, H. T., Cho, J. H., Yoo, J. Y., Ro, J. K. and Kim, S. W. (2002), Self-Weight Consolidation Settlement of Soft-Grounds on the Artesian Pressure After the Penetration of Vertical Drain, KGS Fall '02 National Conference, pp.597-604 (in Korean).
  11. Kim, T. H., Yu, J. M., Lee, M. J., Bae, K. H. and Jung, D. S. (2006), A Design Case Study Considering the Artesian Pressure in Hwa Jeon Site of Nakdong Delta Area, Korean Association of Professional Engineers Soil Mechanics & Foundation Engineering, pp.311-319 (in Korean).
  12. Kim, Y. T. and Do, T. H. (2010), Effect of Leaching on the Compressibility of Busan Clay, Journal of Civil Engineering, Vol.14, No.4, pp.291-297.
  13. Nagase H., Shimizu K., Hiro-oka A., Tanoue Y. and Saitoh Y. (2006), Earthquake-induced residual deformation of Ariake clay deposits with leaching, Soil Dynamics and Earthquake Engineering, No.26, pp.209-220.
  14. Ohtsubo, M., Egashira, K. and Takayama, M. (1996), Mineralogy and Chemistry, and Their Correlations with the Geotechnical Properties of Marine Clays in Ariake Bay, Japan: Comparison of Quick and Nonquick Clay Sediments, Journal og Marine Georesources & Geotechnology, Vol.14, No.3, pp.263-282. https://doi.org/10.1080/10641199609388316
  15. Ryu. C. K. (2003), Engineering Geological Characteristics of the Holocene Marine Clayey Sediments in the Estuary of Nagdong River, Pusan University, Master's thesis, pp.1-230 (in Korean).
  16. Ryu, C. K., Kang, S. R, Chung, S. G. and Jeon, Y. M. (2011), Late Quaternary Depositional Environmental Change in the Northern Marginal Area of the Nakdong River Delta, Journal of the Geological Society of Korea, Vol.47, No.3, pp.213-233 (in Korean).
  17. Salem, H. S. and Chilingarian, G. V. (1999), The cementation factor of Archie's equation for shaly sandstone reservoirs, Journal of Petroleum Science and Engineering, Vol.23, No.2, pp.83-93. https://doi.org/10.1016/S0920-4105(99)00009-1
  18. Torrance, K. J. (1974), A laboratory Investigation of the Effect of Leaching on the Compressibility and Shear Strength of Norwegian Marine Clays, Norwegian Geotechnique, Vol.24, No.2, pp.155-173. https://doi.org/10.1680/geot.1974.24.2.155
  19. Woo, S. M., Moh, Z. C. and Burmungsup, T. (1977), Effects of Soil Structure on Compressibility of an Artificially Sedimented Clay, Proceeding of International Symposium on Soft Clay, pp.311-325.