Compressibility Characteristics of Estuarine Clays in the Nakdong River Plain

낙동강 하구점토의 압축특성에 관한 연구

  • 정성교 (동아대학교 토목공학과) ;
  • 곽정민 (동아대학교 토목공학과) ;
  • 장우영 (일본 교토대학 대학원) ;
  • 김덕곤 (동아대학교 토목공학과 대학원)
  • Published : 2002.08.01

Abstract

In the Nakdong River plain a very thick clayey soils are covered widely. Since the early 1990's, some huge reclamation projects have been performed for the development of industrial and residential complexes and so on. Despite a large number of soil investigations have been carried out for the projects, the geotechnical properties have never been elucidated well, so that the settlements of the ground due to the mischaracterized properties were greatly underestimated. Therefore, it has been needed to evaluate definitely the characteristics of the clayey soils, particularly for the compressibility characteristics to help understand the settlement behavior. For the compressibility characteristics of the Pusan clays, physical index and consolidation tests were conducted on the reconstituted and undisturbed samples. Using the result of physical index, the Pusan clays could be divided into two different units, which have different depositional environments. According to the concepts of Burland (1990) and Nagaraj et. al. (1990), the intrinsic state line and field compression curve of the Pusan clays could be established. It could be found from their concepts that the Pusan clays are under the cemented and young normally consolidated state and largely consisted of two units. The cementation of the clays was as well identified by compression index ratio (Tsuchida et. al.,1991) and sensitivity (Leroueil et. al.,1983).

낙동강하구 지역에는 두터운 점성토 퇴적지반이 넓게 분포되어 있다. 1990년대 초반부터 이러한 점성토 퇴적지반을 이용한 공업 및 주거단지 등의 확보를 위해 개발이 활발하게 진행되어 왔다. 이 과정에서 수많은 지반조사가 실시되었음에도 불구하고 이들 점성토 지반의 토질특성이 명확하게 규명되지 못했으며, 또한 잘못 결정된 토질정수로 인하여 지반침하 예측이 과소평가 되는 등의 문제점을 안고있다. 이러한 침하거동을 이해하기 위해서는 압축특성을 포함한 토질특성을 명확히 규명하는 것이 필요하다. 본 연구에서는, 부산점토의 압축특성을 규명하기 위하여 재구성된 시료와 불교란 시료를 이용하여 기본적인 물성시험과 압밀시험이 수행되었다. 물리적 특성으로부터 부산점토는 상부와 하부층의 구분이 뚜렷하게 나타나며, 퇴적환경이 서로 상이한 것을 알 수 있었다. Bluland(1990)와 Nagaraj(2000)의 연구를 배경으로 부산점토의 고유상태선과 현장압축곡선을 구할 수 있었으며, 부산점토가 고결작용이 발달된 장년기(young) 정규압밀 점토라는 것과 대개 2개의 성질이 다른 지층으로 구성되어 있다는 사실을 알 수 있었다. 또한 압축지수비(Tsuchida et.al.,1991)와 예민비(Leroueil et. al.,1983)로부터 고결효과를 확인할 수 있었다.

Keywords

References

  1. 대한토목학회 논문집 v.21 no.4-C 현장 및 실내시험에 의한 양산 점토의 공학적 특성에 관한 연구 임형덕;김대규;이우진
  2. 가을 학술발표회 논문집 부산점토의 압축특성 정성교;장우영;P.H. Giao;김규종
  3. Geotechnique v.17 Engineering geology of Norwegian normally consolidated marine clay as related to settlement of buildings Bjerrum, L.
  4. Geotechnique v.40 no.3 On compressibility and shear strength of natural clays Burland, J. G. https://doi.org/10.1680/geot.1990.40.3.329
  5. Geotechnique v.29 no.4 A natural compression law for soils (an advance on e-log p') Butterfield, R. https://doi.org/10.1680/geot.1979.29.4.469
  6. Proc. of the 11th ARC on SMGE Engineering properties and consolidation characteristics of Kimhae estuarine clayey soils Chung, S. G.
  7. Canadian Geotechnical Journal Geotechnical properties of Pusan clays Chung, S. G.;Giao, P. H.;Kim, G. J.;Leroueil, S.
  8. Indian Geotechnical Conference-2001 v.2 Challenges in geotechnical investigation of Pusan clays Chung, S. G.;Giao, P. H.
  9. International Workshop on Characterization and Engineering Properties of Natural Soils Geotechnical characteristics and engineering problems of Pusan clays Chung, S. G.;Giao, P. H.;Tanaka, H.
  10. Soils and Foundations v.38 no.2 A method of correcting yield stress and compression index of Ariake clays for sample disturbance Hong, Z.;Onitsuka, K. https://doi.org/10.3208/sandf.38.2_211
  11. Canadian Geotechnical Journal v.36 On compression characteristics of Ariake clays Hong, Z;Tsuchida, T. https://doi.org/10.1139/cgj-36-5-807
  12. KGS 99 Dredging and Geoenvironmental Conference Large consolidation settlement occurred during reclamation works in the Nakdong river mouth Kim, S. K.
  13. Canadian Geotechnical Journal v.20 no.4 Proprietes caracteristiques des argiles de lest du Leroueil, S.;Tavenas, F.;Le Bihan, J. P. https://doi.org/10.1139/t83-076
  14. KGS '99 Dredging an Geoenvironmental Conference Microstructure, mineralogy and physical properties: techniques and application to the Pusan clays Locat, J.;Tanaka, H.
  15. The BK21 Invitation Lecture Naturally and induced cemented soft clays - Analysis and assessment of their behaviour Nagaraj, T. S.
  16. Journal of Geotechnical Engrg. v.116 no.1 Analysis of compressibility of sensitive soils Nagaraj, T.S.;B.R.S. Murthy;A. Vatsala;R.C. Joshi https://doi.org/10.1061/(ASCE)0733-9410(1990)116:1(105)
  17. Report of the Port and Harbour Research Institute v.17 no.3 Correlations of geotechnical parameters in port and harbor area Ogawa, F.;Matsumoto, K.
  18. International Seminar on Geotechnics in Kochi The mysterious formation of Nakdong river estuary soft soil Park, S.Z.;G.H. Jeong;J.H. Park;F.E. Bautista;S. Suwa;M. Fukuda;H. Tanaka;O. Mishima;M. Tanaka
  19. Soils and Foundations v.41 no.2 Charcterization of Yangsan clay, Pusan, Korea Tanaka, H.;Mishima, O.;Tanaka, M.;Park, S. Z.;Jeoung, G.H.;Locat, J. https://doi.org/10.3208/sandf.41.2_89
  20. Soils and Foundations v.31 no.4 Effect of aging of marine clays and its duplication by high temperture consolidation Tsuchida, T.;Kobayashi, M.;Mizukami, J. https://doi.org/10.3208/sandf1972.31.4_133
  21. IS-Yokohama 2000 Mechanical properties of Pleistocene clay and evaluation of structure due to aging Tsuchida, T.