한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

  • 제28권8호
  • /
  • Pages.5-19
  • /
  • 2012
  • /
  • 1229-2427(pISSN)
  • /
  • 2288-646X(eISSN)
한국지반공학회 (Korean Geotechnical Society)
권호 표지
DOI QR코드

DOI QR Code

준설매립지반의 자중압밀을 고려한 2차원 축대칭 비선형 유한변형 압밀 모델

2-D Axisymmetric Non-linear Finite Strain Consolidation Model Considering Self-weight Consolidation of Dredged Soil

  • 곽태훈 ((주) 동명기술공단) ;
  • 이동섭 (고려대학교 건축사회환경공학부) ;
  • 임지희 (고려대학교 건축사회환경공학부) ;
  • 티모시 스탁 (미 일리노이대 토목환경공학과) ;
  • 최은석 ((주)서신엔지니어링) ;
  • 최항석 (고려대학교 건축사회환경공학부)
  • 투고 : 2011.09.18
  • 심사 : 2012.08.10
  • 발행 : 2012.08.31
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

준설매립지반 설계시 압밀 소요시간 단축을 위해 연직배수공법와 선행재하공법등의 연약지반 개량공법을 주로 적용한다. 준설매립지반의 자중에 의한 압밀이 완료되기까지는 많은 시간이 소요되므로 공사비 절감, 공기단축의 이유로 연약지반 개량공법은 일반적으로 자중압밀 도중 적용된다. 본 논문에서는 준설매립지반에서 연직방향으로 자중압밀이 진행되는 도중 연직배수재 타설에 의해 방사방향의 흐름이 추가로 발생하는 경우의 압밀거동 예측을 위하여 자중압밀을 고려한 2차원 축대칭 비선형 유한변형 압밀 지배방정식과 이를 적용하기 위한 수치모델(Axi-Selcon)을 개발하였다. Axi-Selcon의 검증과 자중압밀 도중 연직배수재가 타설된 준설매립지반을 모사하기 위해 일련의 실내시험을 수행하였다. 이를 위해 연직배수재가 타설된 준설매립지반을 모사하는 대형자중압밀 시험기를 고안하였다. 모델의 추가적인 검증을 위하여 기존에 제안된 간편 해석법을 적용한 결과와 Axi-Selcon의 해석결과와 비교하였다. 마지막으로, Axi-Selcon을 적용하여 가상의 대심도 준설매립지반의 거동을 예측하였다. 이와 같은 일련의 모델 검증과정을 통해 본 논문에서 개발된 Axi-Selcon은 자중압밀 도중 연직배수재 타설과 선행재하공법이 적용될 경우에 대한 초연약 준설매립지반의 압밀 거동을 적절히 예측할 수 있음을 보였다.

Vertical drains along with the preloading technique have been commonly used to enhance the consolidation rate of dredged placement formation. In practice, vertical drains are usually installed in the process of self-weight consolidation of a dredged soil deposit because this process takes considerable time to be completed, which makes conventional analytical or numerical models difficult to quantify the consolidation behavior. In this paper, we propose a governing partial differential equation and develop a numerical model for 2-D axisymmetric non-linear finite strain consolidation considering self-weight consolidation to predict the behavior of a vertical drain in the dredged placement foundation which is installed during the self-weight consolidation. In order to verify the developed model in this paper, results of the numerical analysis are compared with that of the lab-scaled self-weight consolidation test. In addition, the model verification has been carried out by comparing with the simplified method. The comparisons show that the developed model can properly simulate the consolidation of the dredged placement formation with the vertical drains installed during the self-weight consolidation. Finally, the effect of construction schedule of vertical drains and of pre-loading during the self-weight consolidation is examined by simulating an imaginary dredged material placement site with a thickness of 10 m and 20 m, respectively. This simulation infers the applicability of the proposed method in this research for designing a soil improvement in a soft dredged deposit when vertical drains and pre-loading are implemented before the self-weight consolidation ceases.

키워드

참고문헌

  1. An, Y. (2010), Experimental Study of Two-dimensional Axisymmetric Non-linear Finite Strain Consolidation Theory, MS thesis, Korea University, Seoul, Republic of Korea.
  2. An, Y., Kwak, T., Lee, C., Choi, H. and Choi, E. (2010), "Nonlinear Finite Strain Consolidation of Ultra-soft Soil Formation Considering Radial Drainage", Journal of Korean Geotechnical Society (KGS), Vol.26, No.11, pp.17-28.
  3. An, Y., Kwak, T., Lee, C., Choi, H. and Choi, E. (2010), "Nonlinear Finite Strain Consolidation of Ultra-soft Soil Formation Considering Radial Self-weight Consolidation", Proceedings of Korean Geotechnical Society Spring Conference, KGS, pp.495-508.
  4. Archie, G. E. (1942), "The electrical resistivity log as an aid in determining some reservoir characteristics", Transactions of the American Institute of Mining, Metallugical, and Petroleum Engineers, Vol.146, pp.54-62.
  5. ASTM D 4186-82, "Standard test method for one-dimensional consolidation properties of soils using controlled strain loading", American Society for testing and Materials, Philadelphia, USA.
  6. Barron, R. A. (1948), "Consolidation of fine-grained soils by drain wells", Transactions, American Society of Civil Engineers, Vol.113, pp.718-742.
  7. Cargill, K. W. (1982), "Consolidation of soft layers by finite strain analysis", Miscellaneous Paper GL-82-3, US Army Engineer Waterways Experiment Station, MS.
  8. Cargill, K. W. (1983), "Prediction of consolidation of very soft soil", Journal of Geotechnical Engineering, Vol.110, No.6.
  9. Cargill, K. W. (1986), "The large strain, controlled rate of strain (LSCRS) device for consolidation testing of soft fine-grained soils", Technical Report GL-86-13, Waterways Experiment Station, Corps of Engineer, Vicksburg, MI
  10. Carillo, N. (1942), "Simple two and three dimensional caese in the theory of consolidation of soils", Journal of Mathematics and Physics, Vol.21, No.1, pp.1-5.
  11. Gibson, R. E., England, G. L. and Cargill, K. W. (1967), "The theory of one-dimensional consolidation of saturated clays. I. Finite non -linear consolidation of thin homogeneous layers", Geotechnique, Vol.17, No.3, pp.261-273. https://doi.org/10.1680/geot.1967.17.3.261
  12. Hindebrand, F. B. (1949), "Advanced calculus for engineers", Prentice-Hall, Englewood Cliffs, N. J.
  13. Imai, G. (1981), "Experimental studies on sedimentation mechanism and sediment formation of clay materials", Soil and Foundations, Vol.21, No.1, pp.7-20. https://doi.org/10.3208/sandf1972.21.7
  14. Kwak, T., Lee, C., Lim, J., An, Y. and Choi, H. (2011), "Analysis Method for Non-Linear Finite Strain Consolidation for Soft Dredged Soil Deposit Part I: Parameter Estimation for Analysis", Journal of Korean Geotechnical Society (KGS), Vol.27, No.9, pp.13-24.
  15. Lo, D. O. K. (1991) Soil Improvement by Vertical Drains, PhD. Dissertation, Univ. of Illinois at Urbana-Champaign, USA.
  16. Mesri, G. and Godlewski, P. M. (1977), "Time- and stress -compressibility interrelationships", Journal of Geotechnical Engineering, ASCE, Vol.103, No.5, pp.417-430.
  17. Morris, P. H. (2002), "Analytical solutions of linear finite-strain one -dimensional consolidation", Journal of geotechnical and geoenvironmental engineering, Vol.128, No.4, pp.319-326. https://doi.org/10.1061/(ASCE)1090-0241(2002)128:4(319)
  18. Stark, T. D., Choi, H. and Schroeder, P. R. (2005), "Settlement of dredged and contaminated material placement areas, I : Theory and use of primary consolidation, secondary compression, and desiccation of dredged fill", Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, Vol.131, No.2, pp.43-51. https://doi.org/10.1061/(ASCE)0733-950X(2005)131:2(43)
  19. Stark, T. D., Choi, H. and Schroeder, P. R. (2005), "Settlement of dredged and contaminated material placement areas, II : Primary consolidation, secondary compression, and desiccation of dredged fill input parameters", Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, Vol.131, No.2, pp.52-61. https://doi.org/10.1061/(ASCE)0733-950X(2005)131:2(52)
  20. Wissa, A. E. Z., Christian, J. T., Davis, E. H. and Heilberg, S., (1971), "Consolidation at constant rate of strain", Journal of the Soil Mechanics and Foundations Division, ASCE, Vol.97, No.SM10, pp.1393-1413.
  21. Znidarcic, D. (1999), "Predicting the behavior of disposed dredging soils", Geotechnical Engineering for Transportation Infrastructure, Proceedings of the 12th European Conference on Soil Mechanics and Geotechnical Engineering, Vol.2, pp.877-886.