KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Finite Difference Modeling of a Piled Raft Foundation with Axisymmetry Condition and Interface Element

축대칭 조건 및 경계면 요소를 이용한 Piled Raft 기초의 유한차분 모델링 연구

  • 유광호 (수원대학교 토목공학과) ;
  • 김형렬 (수원대학교 토목공학과) ;
  • 배상한 (수원대학교 토목공학과)
  • Received : 2015.01.21
  • Accepted : 2015.06.03
  • Published : 2015.08.01
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Abstract

In this study, FDM modelling with axisymmetry condition and interface element was verified whether it is reasonable to estimate compositive behavior of a piled raft foundation. To this end, the modelling validity of piled raft foundations was estimated by comparing and analyzing numerical analysis results and laboratory model test results. Also, load bearing ratio of a raft is analyzed by performing sensitivity analysis of foundation parameters with the actual field conditions. As a result of this study, correlation between bearing capacity and vertical displacement of numerical results turned out to be similar with that of a laboratory model test. In addition, ultimate bearing capacity of piled rafts and load bearing ratio of the raft is calculated to be similar in both cases. The load bearing ratio of the raft was also estimated to be in the range of 33% to 52% from the sensitivity analysis. The results were confirmed to be similar to the previous studies. Therefore, it can be inferred that piled rafts can be effectively modelled applying axisymmetry condition and interface element.

본 연구에서는 수치해석을 이용한 piled raft 기초의 복합적인 거동평가를 위해 축대칭 조건 및 경계면 요소를 적용한 유한차분해석 모델링 방법이 합리적인지 검증하였다. 이를 위해 실내모형실험 결과와 수치해석 결과를 비교 분석하여 piled raft 기초의 모델링 방법의 적합성을 평가하였다. 그리고 실제 현장조건을 고려한 기초 매개변수에 대한 민감도분석을 수행하여 raft의 하중분담율을 분석하였다. 연구 결과, 실내모형실험과 수치해석 결과에서 지지력-수직변위의 상관관계가 동일한 경향을 보였으며, piled raft 기초의 극한지지력과 raft의 하중분담율이 비교적 유사하게 산정되었다. 그리고 민감도분석을 통해 raft의 하중분담율은 약 33%~52% 사이에서 산정되어, 기존 연구 결과와 유사함을 확인하였다. 따라서 piled raft 기초는 축대칭 조건 및 경계면 요소를 이용하여 효과적으로 모델링될 수 있을 것으로 판단된다.

Keywords

References

  1. Choi, K. J. (2013). Analysis of behavior and load sharing of piled rafts, Master's Dissertation, Yonsei University (in Korean).
  2. Gunaratne, M. (2005). The foundation engineering handbook, CRC Press, Boca Raton.
  3. Itasca Consulting Group, Inc. (2005). Fast Lagrangian Analysis of Continua, Ver. 5.0, Itasca Consulting Group, Minnesota, USA.
  4. Jeang, Y. K. (2004). Study on soil properties and earth pressure at domestic multi-layer, Master's Dissertation, Hankyong National University (in Korean).
  5. Jeon, S. K. (1998). Design manuals of foundation structure for practitioners, Sciencebook (in Korean).
  6. Kateznbach, R. and Reul, O. (1997). "Design and performance of piled rafts." Proc. 14th ICSMFE, Hamburg, Vol. 4, pp. 2,253-2,256.
  7. Kim, B. S. (2013). Finite element analysis on the behavior of piled raft installed in soft clay, Master's Dissertation, Pukyong National University (in Korean).
  8. Kim, C. K. (2002). 3-D Behavior of adjacent structures in tunnelling induced ground movement, Master's Dissertation, Dankook University (in Korean).
  9. Kim, H. R. (2014). The estimation of bearing capacity for a piled raft foundation using finite element method, Master's Dissertation, University of Suwon (in Korean).
  10. Kim, S. M. (2008). Analysis of axial load sharing of piled raft in layered soil, Master's Dissertation, Yonsei University (in Korean).
  11. Kim, T. J. (2013). A numerical investigation on end bearing capacity of single pile installed in fractured rock mass, Master's Dissertation, Sungkyunkwan University (in Korean).
  12. Korean Agency for Technology and Standards (KATS) (2014). Pretensioned spun high strength concrete piles, KS F 4306 (in Korean).
  13. Lee, J. H., Cho, H. Y., You, K. H. and Jeong, S. S. (2012). "A study on the ultimate point resistance of rock socketed drilled shafts using FLAC 3D and UDEC." Journal of the Korean Geotechnical Society, Vol. 28, No. 1, pp. 29-39 (in Korean). https://doi.org/10.7843/kgs.2012.28.1.29
  14. Lee, W. (2003). A study on load bearing ratio of raft in piled raft on granular soil, Ph.D. Dissertation, Keimyung University (in Korean).
  15. O'Neill, M. W. and Hassan, K. M. (1994). "Drilled shaft : Effects of Construction on Performance and Design criteria." Federal Highways Administration, Vol. 1, pp. 137-187.
  16. Park, S. K. (2001). A study on the interaction of the piled raft foundation from model test, Master's Dissertation, Hongik University (in Korean).
  17. Seo, Y. K. (2004). "Piled-raft foundation on soft clay in Gimhae area." Journal of Ocean Engineering and Technology, Vol. 18, No. 3, pp. 20-25 (in Korean).
  18. Song, J. W. (2003). A study on load bearing capacity of piled raft using finite element analysis, Master's Dissertation, Sunmoon University (in Korean).

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