Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical Simulation of Dynamic Soil-pile-structure Interaction in Liquefiable Sand

액상화 가능한 지반에 근입된 지반-말뚝-구조물 동적 상호작용의 수치 모델링

  • 권선용 (한국환경정책.평가연구원) ;
  • 유민택 (한국철도기술연구원) ;
  • 김석중 (한국건설기술연구원 지반연구소)
  • Received : 2018.05.31
  • Accepted : 2018.06.20
  • Published : 2018.07.31
Download PDF
⟨ Previous Next ⟩

Abstract

Three-dimensional continuum modeling of dynamic soil-pile-structure interaction embedded in a liquefiable sand was carried out. Finn model which can model liquefaction behavior using effective stress method was adopted to simulate development of pore water pressure according to shear deformation of soil directly in real time. Finn model was incorporated into Non-linear elastic, Mohr-Coulomb plastic model. Calibration of proposed modeling method was performed by comparing the results with those of the centrifuge tests performed by Wilson (1998). Excess pore pressure ratio, pile bending moment, pile head displacement-time history according to depth calculated by numerical analysis agreed reasonably well with the test results. Validation of the proposed modeling method was later performed using another test case, and good agreement between the computed and measured values was observed.

액상화 시 지반-말뚝 시스템의 동적 거동을 정확히 예측하기 위해 상용 유한 차분 프로그램인 FLAC3D를 이용하여 시간영역에서 3차원 수치 모델링을 수행하였다. 지반의 전단변형에 따른 간극수압의 발달을 직접적으로 모사하기 위해 유효응력 해석법을 이용한 액상화 모델인 Finn model을 적용하였으며 Mohr-Coulomb 탄소성 모델에 접목되어 해석이 수행되었다. 이력감쇠모델을 적용하여 지반 비선형 거동을 고려하였으며 지반과 말뚝 간의 분리현상, 미끄러짐 현상을 모사하는 인터페이스 모델을 적용하였다. 경계조건으로써 단순화 연속체 모델링 기법을 도입하여 반사파의 생성을 막고 해석 효율을 증가시켰으며 적절한 최대지반탄성계수와 항복 깊이의 설정으로 비선형 거동을 정확히 모사하고자 하였다. Wilson(1998)이 수행한 원심모형시험 케이스 중 상부지반 상대밀도가 55%인 모델을 이용하여 제안된 모델링 기법의 캘리브레이션을 수행한 결과, 수치해석으로부터 도출된 깊이 별 과잉간극수압 비-시간 이력, 휨모멘트-시간이력, 말뚝 두부 변위-시간이력이 실험 결과를 잘 모사하였다. 상부지반 상대밀도가 30%인 모델의 결과를 이용하여 제안된 모델링 기법의 적용성 평가를 수행한 결과, 수치해석으로부터 도출된 지반 및 말뚝 응답이 실험 결과를 잘 모사하였으며 제안된 모델링 기법이 지반-말뚝 시스템의 액상화 거동을 적절히 모사한다고 판단되었다.

Keywords

References

  1. Beringen, F. L., Windle, D., and Van Hooydonk, W. R. (1979), "Results of Loading Tests on Driven Piles in Sand", Fugro.
  2. Byrne, P. (1991), "A Cyclic Shear-volume Coupling and Porepressure Model for Sand. in Proceedings", Second International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics. St. Louis, Missouri. March. 1(24): 47-55.
  3. Cheng, Z. h. and Jeremic, B. (2009), "Numerical Modeling and Simulation of Pile in Liquefiable Soil", Soil Dynamics and Earthquake Engineering, 29(11-12): 1404-16.
  4. Finn, W. D. L. and Fujita, N. (2002), "Pile in Liquefiable Soils: Seismic Analysis and Design Issues", Soil Dynamics and Earthquake Engineering, 22(9-12): 731-742. https://doi.org/10.1016/S0267-7261(02)00094-5
  5. Fujii, S., Isemoto, N., Satou, Y., and Kaneko, O. (1998), "Investigation and Analysis of a Pile Foundation Damaged by Liquefaction during the 1995 Hyogoken-Nambu Earthquake. Soils and Foundations", Special issue on geotechnical aspects of the 17 January 1995 Hyogoken-Nambu Earthquake, No.2, pp.179-192.
  6. Hardin, B. O. and Drnevich, V. P. (1972), "Shear Modulus and Damping in Soils: Design Equations and Curves", Journal of the Soil Mechanics and Foundations Division, ASCE, 98(SM7): 667-692.
  7. Itasca Consulting Group (2006), "FLAC3D (Fast Lagrangian Analysis of Continua in 3Dimensions) User's Guide", Minnesota, USA.
  8. Kagawa, T. and Kraft, L. (1981), "Lateral Pile Response During Earthquakes", J. Geotech. Eng., ASCE, 107(12), pp.1713-1731
  9. Kim, S. H., Kwon, S. Y., Kim, M. M., and Han, J. T. (2012), "3D Numerical Simulation of a Soil-pile System under Dynamic Loading", Marine Georesources and Geotechnology, 30(4): 347-361. https://doi.org/10.1080/1064119X.2012.657997
  10. Klar, A. and Frydman, S. (2002), "Three-Dimensional Analysis of Lateral Pile Response using Two-Dimensional Explicit Numerical Scheme", Journal of Geotechnical and Geoenvironmental Engineering, 128(9): 775-784. https://doi.org/10.1061/(ASCE)1090-0241(2002)128:9(775)
  11. Kraft Jr, L. M. (1990), "Computing Axial Pile Capacity in Sands for Offshore Conditions", Marine Georesources & Geotechnology, 9(1): 61-92. https://doi.org/10.1080/10641199009388230
  12. Kwon, S. Y., Kim, S. J., and Yoo, M. T. (2016), "Numerical Simulation of Dynamic Soil-pile Interaction for Dry Condition Observed in Centrifuge Test", Journal of the Korean Geotechnical Society, 32(4): 5-14. https://doi.org/10.7843/kgs.2016.32.4.5
  13. Liyanapathirana, D. S. and Poulos, H. G. (2005), "Seismic Lateral Response of Piles in Liquefying Soil", Journal of geotechnical and geoenvironmental engineering, 131(12): 1466-1479. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:12(1466)
  14. Martin, G. R., Finn, W. D. L., and Seed, H. B. (1975), "Fundamentals of Liquefaction under Cyclic Loading", Journal of Geotechnical and Geoenvironmental Engineering, 101(ASCE# 11231 Proceeding).
  15. Oka, F., Lu, C. W., Uzuoka, R., and Zhang, F. (2004), "Numerical Study of Structure Soil-group Pile Foundations using an Effective Stress based Liquefaction Analysis Method", In Proceedings: 13th World conference on earthquake engineering, Canada. Vancouver. 3338.
  16. Popescu R. and Prevost J. H. (1993), "Centrifuge Validation of a Numerical Model for Dynamic Soil Liquefaction", Soil Dynamics and Earthquake Engineering, 12, 73-90. https://doi.org/10.1016/0267-7261(93)90047-U
  17. Randolph, M. F., Dolwin, R., and Beck, R. (1994), "Design of Driven Piles in Sand", Geotechnique, 44(3): 427-448. https://doi.org/10.1680/geot.1994.44.3.427
  18. Reddy, E. S., Chapman, D. N., and Sastry, V. V. (2000), "Direct Shear Interface Test for Shaft Capacity of Piles in Sand", Geotechnical Testing Journal, 23(2): 199-205. https://doi.org/10.1520/GTJ11044J
  19. Seed, H. B. and Idriss, I. M. (1970), "Soil Moduli and Damping Factors for Dynamic Response Analyses", Report to EERC-70/10; Earthquake Engineering Research Center, Univ. of California at Berkeley, Berkeley, CA.
  20. Wilson, D. W. (1998), "Soil-pile-superstructure Interaction in Liquefying Sand and Soft Clay", Ph.D. dissertation, University of California, Davis. USA.
  21. Yang, E. K. (2009), "Evaluation of Dynamic p-y Curves for a Pile in Sand from 1g Shaking Table Tests", Ph. D. Dissertation, Seoul National University. South Korea.
  22. Yao S., and Nogami T. (1994), "Lateral Cyclic Response of Piles in Viscoelastic Winkler Subgrade", J Eng Mech, 120(4): 758-75. https://doi.org/10.1061/(ASCE)0733-9399(1994)120:4(758)