Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
권호 표지
DOI QR코드

DOI QR Code

Stress Concentration Ratio According to Penetration Rate of Composite Ground Reinforced with GCP

GCP로 개량된 복합지반의 관통률에 따른 응력분담비

  • Na, Seung-Ju (Department of Civil Engineering, Chosun Univ.) ;
  • Kim, Daehyeon (Department of Civil Engineering, Chosun Univ.) ;
  • Lee, Ik-Hyo (Department of Marine and Civil Engineering, Chonnam National Univ.) ;
  • Lee, Kang-Il (School of Civil and Environmental Engineering, Urban Design and Study, Daejin Univ.)
  • Received : 2017.05.02
  • Accepted : 2017.06.10
  • Published : 2017.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

Gravel compaction pile (GCP) is widely used as it increases the bearing capacity of soft ground and reduces the consolidation settlement. Stress concentration ratio for design is dependent on the area replacement, surcharge pressure, depth and penetration rate. However, a range of stress concentration ratio obtained through field, laboratory experiments and numerical analysis is large. But since the main objective of the study is to evaluate the stress concentration ratio and settlement for both area replacement ratio and penetration rate through numerical analysis. Numerical analysis using the finite element program ABAQUS 6.12-4 has been performed for the composite ground with GCP. As a result, the stress concentration ratio at the points except for the point of top is in the range of 1.21-5.36, 1.19-5.45, 2.16-5.60 for 60%, 80% and 100% penetration, respectively. In general, as the penetration rate and area replacement ratio increases, the stress concentration ratio tends to increase.

쇄석다짐말뚝(GCP)은 연약지반의 지지력 증가와 침하량 감소를 실현할 수 있어 연약지반 개량에 활발하게 사용되고 있다. 그리고 GCP 설계에 필요한 응력분담비는 치환율, 상재하중, 깊이, 관통률 등에 따라 달라진다. 그동안 많은 연구자들이 현장 실내 실험, 수치해석 연구를 통해 GCP로 개량된 복합지반의 응력분담비를 제안하였지만 명확하게 제시되지 못한 실정이다. 본 연구에서는 GCP공법의 합리적인 설계법 제안을 위한 기초연구로써, 유한요소해석프로그램인 ABAQUS 6.12-4를 이용하여 GCP로 개량된 복합지반을 모델링하여 치환율과 관통률에 따른 침하량과 응력분담비를 분석하고자 하였다, 그 결과, 최상부 지점을 제외한 다른 지점에서의 응력분담비의 값은 관통률 60%일 때 1.21~5.36, 관통률 80%일 때 1.19~5.45, 관통률 100%일 때 2.16~5.60 이었다. 이는 관통률과 치환율이 증가할수록 응력분담비의 값은 크게 증가함을 알 수 있다.

Keywords

References

  1. Bae, K.T. and Lee, C.K. (2007), "The Behavior of Rammed Aggregate Piers (RAP) in Soft Gmund (1)", Journal of Korean Geotechnical Society, Vol.23, No.4, pp.169-183.
  2. Busan New Port Corp. (1999), Report of North Container Terminal, pp.6.50-6.59.
  3. Dassault Systemes. (2008), Abaqus Version 6.12 Documentation. Providence, RI: Dassault Systemes.
  4. Goughnour, R.R. and Bayuk, A. A.(1979), "Analysis of stone column-soil matrix interaction under vertical load", Colleque International sur le reinforcement dessols, Paris, France, Vol.1, pp.271-277.
  5. Jeong, G. C., Heo, Y., and Bae, W. S. (2012), Behavior of Soft Ground Improved with Fully-Partly Penetrated Sand Compaction Piles, Journal of the Korean Geotechnical Society, Vol.13, No.9, pp.91-99.
  6. Ju, K. W. (2004), Consoildation Analysis of Soils Improved by Partly Penetrated SCP with Low Replacement Ratio, Master's Thesis, Univerity of Daejin, pp.1-95.
  7. Kang, J. G. (1998), Study on the Determination Methods of the Stress Concentration Ratio in SCP Method, Master's Thesis, University of Myungji, pp.1-57.
  8. Kim, J. H. (2009), (The) Experimental Study on Composite Ground Behavior and Aspect of Clay Gone Through Compaction Pile of Recycled Aggregate Compaction Piles, Hongik University, Master Thesis.
  9. Kim, Y. N. (2003), Study on the Consoildation Behavior of Cohesice Soils Improved by Penetratted and Partly Penetrated Sand Compaction Piles, Master's Thesis, Univerity of Suwon, pp.1-109.
  10. Kolekar, Y. A. and Murty, D. (2011), Numerical Simulation of Behavior of Partially Penetration Stone Coulomns, Pan-Am CGS Geotechnical, pp.107-112.
  11. Lee, C. H., Lim, H. D., and Lee, W. J. (2005), "Finite Element Analysis of GCP Ground with Replacement Ratio", KSCE Journal of Civil Engineering, Vol.2005, No.10, pp.5459-5462.
  12. Lee, K. I., Lee, J. W., Im, E. S., and Ju, K. W. (2012), Consoildation Analysis of Soils Improved by Partly Penetrated SCP with Degree of Consoildation and Replacement Ratio, Journal of the Korean Geosynthetic Society, Vol.11, No.2, pp.11-20. https://doi.org/10.12814/jkgss.2012.11.2.011
  13. Lee, M. H., Choi, Y. G., Im, J. C., and Hawng, G. B. (2003), "A Study on the Stress Concentration of Crushed-stone Compaction Piles through Field Loading Test", Journal of Korean Geotechnical Society, Vol.19, No.6, pp.107-114.
  14. Lee, M. H. (2004), A Study on the Load Support Mechanism and Stress Distribution Characteristic of Crushed-Stone Compaction Piles, Busan University, Master Thesis.
  15. Mohamed, E. and Basuony, E. G. (2016), Behavior of Raft Foundation Resting on Improved Soft Soil with Conventional Granular Piles, Journal of Scientific and Engineering Research, Vol.3, No.4, pp.428-434.
  16. Na, S.J., Kim, M.S., Park, K.H., and Kim, D. H. (2016), Stress Concentration Ratio of GCP Depending on the Mixing Ratio of Crushed Stone and Sand, Journal of the Korean Geotechnical Society, Vol.32, No.9, pp.37-50. https://doi.org/10.7843/KGS.2016.32.9.37
  17. Park, Y. W., Yoon, G. L., Moon, D. J., Kim, B. I., Lee, S. I., and Kwon, O. S. (2000), Behavior characteristics of Sand Compaction Pile with Varying Atea Replacement Ratio, Journal of the Korean Geotechnical Society, Vol.16, No.4, pp.117-128.
  18. Shin, H. Y. (2005), Analysis on the Behavior of Composite Ground Reinforced by Sand Compaction Pile with Low Area Replacement Ratio, Ph. D Dissertation, Univerity of Chungang, pp.1-241.
  19. Song, M. G., Bae, W. S., Ahn, S. R., and Heo, Y. (2011), "Centrifugal Model Test on Stress Concentration Behaviors of Composition Ground under Flexible/Stiff Surcharge Loadings", Journal of Korean Geo-Environmental Society, Vol.12, No. 6, pp.5-15.
  20. The Korea Expressway Corporation. (2009), Road Design Procedure, Part 2 Earthwork and Drainage.
  21. Transport and Marintime Affairs. (2012), Handbook of Road Design, Part 3 Earthwork and Drainage.