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2022 Vol.38, Issue 9 Preview Page
Three-Dimensional Numerical Analysis for Verifying Behavioral Mechanism and Bearing Capacity Enhancement Effect According to Tip Elements

선단 고정 지압구의 거동 메커니즘과 형상에 따른 지지력 증대효과 검증을 위한 3차원 수치해석

Seokhyung Lee1*
,
Seok-Jung Kim2
,
Jin-Tae Han3
,
Hyun-Sik Jin4
,
Gyu-Cheol Hwang5
,
Jeong-Seob Lee6
이 석형1*
,
김 석중2
,
한 진태3
,
진 현식4
,
황 규철5
,
이 정섭6
1Member, Postdoctoral Researcher, Korea Institute of Civil Engrg. and Building Technology
2Member, Senior Researcher, Korea Institute of Civil Engrg. and Building Technology
3Member, Research Fellow, Korea Institute of Civil Engrg. and Building Technology
4Member, CEO, Hydraulic and Geotechnical Consultants
5Member, CEO, Jaesung Construction Co. Ltd.
6Manager, Sejin E&C Co. Ltd.
1정회원, 한국건설기술연구원 박사후연구원
2정회원, 한국건설기술연구원 수석연구원
3정회원, 한국건설기술연구원 연구위원
4정회원, ㈜에이치앤지컨설턴트 대표이사
5정회원, 재성건설 대표이사
6비회원, ㈜세진이엔시 과장
*Corresponding Author
30 September 2022. pp. 53-67
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Abstract

Micropiles are cast-in-place-type piles with small diameters. They are widely used for the foundation reinforcement of existing buildings and structures because this technique is easy to construct and economic. A base expansion structure is developed following the mechanism of radial expansion at the pile tip under compression. Numerical analysis, durability tests, and centrifuge tests have been conducted using the base expansion structure. In this study, three-dimensional numerical modeling was performed to describe the behavioral mechanism of the base expansion structure using steel bar penetration under compressive loading, and numerical analyses using centrifuge test conditions were performed for the comparative studies. Additionally, the base structure was modified based on the results of lab-scale analyses, and the bearing capacities of micropiles were compared using field-scale numerical analyses under various ground conditions.

Keywords
Base expansion
Earth pressure
Foundation reinforcement
Micropile
Numerical analysis

마이크로파일은 소구경 현장타설말뚝으로, 시공방법이 간단하고 공사비용이 상대적으로 저렴하여 건축물을 비롯한 각종 구조물의 보수보강 및 증축 시 기초보강 등에 활용되고 있다. 시공이 용이하고 간단한 메커니즘의 구조체를 선단에 장착하여 지지력을 증대시키는 선단 확장형 마이크로파일이 개발되었으며, 이에 대한 수치해석, 내구성시험, 원심모형시험 등의 연구가 수행되어 왔다. 본 연구에서는, 기존에 수행된 수치모델링을 고도화하여 연직하중 재하에 의해 연결강봉 근입 시 고정 지압구가 활착되는 거동 메커니즘을 확인하고, 원심모형실험과 동일한 조건에서의 수치해석을 수행하여 그 결과를 비교하였다. 또한, Lab-scale 수치해석 결과를 바탕으로 고정 지압구의 형상 개선안을 도출하고, Field-scale 수치해석을 통해 일반 마이크로파일 대비 지지력 증대효과를 비교·검증하였다.

References
1
Han, J.T., Kim, S.R., Jang, Y.E., and Lee, S.H. (2013), Evaluation of Bearing Capacity of Waveform Micropile by Numerical Analyses, Journal of Academia-Industrial Technology, Vol.14, No.11, pp.5906-5914. 10.5762/KAIS.2013.14.11.5906
2
Kim, J.H., Kim, S.J., Han, J.T., and Lee, S.H. (2021), Evaluation of the Installation Mechanism of the Micropile with the Base Expansion Structure Using a Centrifuge Model Test, Journal of the Korean Geotechnical Society, 37(11), pp.37-49.
3
Lee, T.H. and Im, J.C. (2006), An Experimental Study on the Reinforcement Effect of Installed Micropiles in the Surround of Footing on Dense Sand, Journal of the Korean Geotechnical Society, Vol.22, No.5, pp.69-81.
4
Hwang, G.C., Ahn, U.J., Lee, J.S., and Ha, I.S. (2018), A Study on the Bearing Characteristics of No-grouted and End-compressed Micropile Adopting Wedge Horizontal, Journal of the Korean Geotechnical Society, Vol.34, No.3, pp.67-75.
5
Lee, S.H., Han, J.T., Jin, H.S., and Kim, S.J. (2021), 3-D Numerical Analysis for the Verification of Bearing Mechanism and Bearing Capacity Enhancement Effect on the Base Expansion Micropile, Journal of the Korean Geotechnical Society, 37(2), pp.19-31.
6
FHWA (2005), "Micropile Design and Construction", Publication No. FHWA NHI-05-039, U.S Department of Transportation, Washington, D.C.
7
Babu, G.L.S., Murthy, B.S., Murthy, D.S.N., and Nataraj, M.S. (2004), Bearing Capacity Improvement Using Micropiles: A Case Study, Geotechnical Special Publications, No. 124, pp. 0895-0563 10.1061/40713(2004)14
8
Fadeev, A.B., Inozemtsev, V.K., and Lukin, V.A. (2003), Effective Micropiles for the Strengthening of Foundations, Soil Mechanics and Foundation Engineering, Vol.40, No.2, pp.69-71 10.1023/A:1024492203444
9
Farouk, A. (2009), Behavior of Micropiles under Vertical Tension and Compression Loads, proceedings of the international conference on soil mechanics and geotechnical engineering, pp.1243-1246
10
Hill, R. (1950), The Mathematical Theory of Plasticity, Oxford University Press, London, U.K.
11
Murthy, B.S., Babu, G.L.S., and Srinivas, A. (2002), Analysis of bearing capacity improvement using micropiles, Ground Improvement, Vol.6, No.33, pp.121-128 10.1680/grim.2002.6.3.121
12
Sabatini, P.J. and Burak T. (2005), Micropile Design and Construction Reference Manual, FHWA-NHI-05-039, U.S Department of Transportation, Washington, D.C.
13
Smith, I.M. and Griffiths, D.V. (1982), Programming the Finite Element Method, John Wiley & Sons, Chisester, U.K., 2nd edition.
14
Vermeer, P.A. and Borst, R. (1984), Non-associated plasticity for soils, Concrete and rock, Heron, 29(3).
Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 38
  • No :9
  • Pages :53-67
  • Received Date : 2022-08-11
  • Revised Date : 2022-08-30
  • Accepted Date : 2022-08-30
  • DOI :https://doi.org/10.7843/kgs.2022.38.9.53
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