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Analysis of Diameter Effects on Skin Friction of Drilled Shafts in Sand

사질토 지반에 설치된 현장타설말뚝의 말뚝지름에 따른 주면마찰력 분석

Sung-June Lee1*
이 성준1*
1Assistant Prof., Dept. of Civil Engineering, Cheongju Univ.
1청주대학교 토목공학과 조교수
*교신저자. *Corresponding Author. 
31 January 2013. pp. 161-170
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Abstract

In this paper, numerical pile segment analysis is conducted with an advanced soil elastoplastic model to investigate the diameter effects on skin friction behaviour of a drilled shaft in sand. Ultimate skin friction and 't-z' behavior from the pile segment analyses for drilled shafts show good agreement with those from design methods. Higher ultimate skin friction for the smaller diameter pile is related to the greater increase in the effective radial stress at the interface due to the localized dilation at and near the pile interface. Stiffer t-z curve for the smaller diameter pile is related to the early occurrence of three shear stages (early, dilation, constant volume shear stages). The diameter effects on ultimate skin friction of drilled shafts are more prominent for denser sand and lower confining pressure.

Keywords
Drilled shafts
Pile diameter
Skin friction
Pile segment analysis
Sand

본 연구에서는 사질토지반의 거동을 상세히 모사할 수 있는 탄소성모델 및 말뚝절편 수치해석을 적용하여 말뚝지름에 따른 사질토지반에 설치된 현장타설말뚝의 주면마찰거동을 분석하였다. 수치해석 결과는 현재 사용되는 설계방법과 비교하여 극한주면마찰력과 t-z거동을 잘 예측하는 것으로 나타났다. 말뚝지름이 감소함에 따라 말뚝-지반 경계면 및 주위지반에 국부적으로 발생되는 체적팽창과 이에 따라 말뚝주면에 발현되는 유효수평응력이 더 크게 발생하기 때문에 극한주면마찰력이 증가하는 것으로 나타났다. 말뚝지름이 감소함에 따라 t-z곡선 기울기의 증가는 말뚝재하에 따라 발생하는 세가지 전단단계(초기, 체적팽창, 및 일정체적 전단단계)가 일찍 발현되기 때문인 것으로 나타났다. 이러한 현장타설말뚝의 말뚝지름에 따른 극한주면마찰력에 대한 영향은 사질토지반의 상대밀도가 증가하고 구속압이 감소할수록 커지는 것으로 나타났다.

References
1
1.ABAQUS (2010). Theoretical user’s manual (ver. 6-10). Dassault Systemes Simulia Corp.
2
2.Boulon, M. and Foray, P. (1986). “Physical and numerical simulation of lateral shaft friction along offshore piles in sand.” Proceedings of 3rd Conference on Numerical Methods in Offshore Piling, Nantes, pp.127-147.
3
3.Cho, C. W., Kim, H. M., and Kim, W. K. (2004). “Bearing Capacity Evaluation of the Drilled Shaft Using Small Scale Model Test.” Journal of Korean Geotechnical Society(KGS), Vol.20, No.5, pp.117-126.
4
4.Christoulas, S. and Frank, R. (1991) “Deformation parameters for pile settlement.” Proceedings of the International Conference on Soil Mechanics and Foundation Engineering.Deformation of Soils and Displacements of Structures X ECSMFE, Florence, Italy, Vol.1, pp.373-376.
5
5.Foray, P., Balachowsky, L., and Rault, G. (1998). “Scale effects in shaft friction due to the localization of deformations.” Proceedings of Centrifuge 98, Tokyo, pp.211-216.
6
6.Korean Geotechnical Society(KGS) (2009). Design Standard for Structure Foundation. Goomibook
7
7.Lee, S. (2004). Behavior of a single micropile in sand under cyclic axial loads. Ph.D. Thesis, University of Illinois at Urbana-Champaign, Urbana, IL.
8
8.Lehane, B. M., Gaudin, C., and Schneider, J. A. (2005). “Scale effects on tension capacity for rough piles buried in dense sand.” Geotechnique, Vol.55, No.10, pp.709-719.
9
9.Ling, H. I. and Liu, H. (2003). “Pressure-level dependency and densification behavior of sand through generalized plasticitymodel.” Journal of Engineering Mechanics, Vol.129, No.8, pp.851-860.
10
10.Nova, R. and Wood, D. M. (1979). “A constitutive model for sand in triaxial compression.” International Journal for Numerical and Analytical Methods in Geomechanics, Vol.3, pp.225-278.
11
11.O’Neill, M. W. and Reese, L. C. (1999). Drilled Shaft: Construction Procedures and Design Methods. Publication No. FHWAIF-99-025, U.S. Department of Transportation, Federal Highway Administration, Washington, DC.
12
12.Pastor, M., Zienkiewicz, O. C., and Leung, K. H. (1985). “Simple model for transient soil loading in earthquake analysis: II. Non- associative models for sands.” International Journal for Numerical and Analytical Methods in Geomechanics, Vol.9, pp.477-498.
13
13.Pastor, M., Zienkiewicz, O. C., and Chan A. H. C. (1990). “Generalized plasticity and the modelling of soil behavior.” International Journal for Numerical and Analytical Methods in Geomechanics, Vol.14, pp.151-190.
14
14.Potts, D. M. and Martins, J. P. (1982). “The shaft resistance of axially loaded piles in clay.” Geotechnique, Vol.32, No.4, pp.369-386.
15
15.Reese, L. C. and O’Neill, M. W. (1988). Drilled Shafts: Construction Procedures and Design Methods. Publication No. FHWAHI-88-042, U.S. Department of Transportation, Federal Highway Administration, Washington, DC.
16
16.Sagon, M. and Chun, B. S. (2005). “Study on the Side Resistance and Size Effect of Rock Socketed Drilled Shafts.” Proceedings of Korea Society of Civil Engineers (KSCE) Conference 2005, KSCE, pp.3976-3979.
17
17.Sagon, M., and Paik, K. H. (2004). “Side Resistance of Rock Socketed Drilled Shafts in Consideration of the Shaft Size Effects.” Journal of Korean Geotechnical Society(KGS), Vol.20, No.9, pp.115-123.
18
18.Sidarta D. E. (2000). Neural network-based constitutive modeling of granular material. Ph.D. Thesis, University of Illinois at Urbana- Champaign, Urbana, IL.
19
19.Stewart, J. P. and Kulhawy, F. H. (1981). “Experimental investigation of the uplift capacity of drilled shaft foundations in cohesionless soil.” Contract Report B-49(6), Niagara Mohawk Power Corporation, Syracuse, NY; also, Geotechnical Engineering Report 81-2, Cornell University.
20
20.Turner, J. P. and Kulhawy, F. H. (1994). “Physical modeling of drilled shaft side resistance in sand.” Geotechnical Testing Journal, Vol.17, No.3, pp.282-290.
21
21. Zienkiewicz, O. C., Leung, K. H., and Pastor, M. (1985). “Simple model for transient soil loading in earthquake analysis: I. Basic model and its application.” International Journal for Numerical and Analytical Methods in Geomechanics, Vol.9, pp.453-476.
Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 29
  • No :1
  • Pages :161-170
  • Received Date : 2012-12-17
  • Accepted Date : 2013-01-08
  • DOI :https://doi.org/10.7843/kgs.2013.29.1.161
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