Effect of Configuration of Shaft and Helix Plate on Bearing Capacity of Moderate-size Helical Pile : II. Bearing Capacity Prediction

Jongwon Lee; Dongseop Lee; Kyunguk Na; Hangseok Choi

doi:10.12814/jkgss.2014.13.2.041

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2014 Vol.13, Issue 2 Preview Page Next Page

Effect of Configuration of Shaft and Helix Plate on Bearing Capacity of Moderate-size Helical Pile : II. Bearing Capacity Prediction 중소구경 헬리컬 파일의 축과 원판의 형상이 지지력에 미치는 영향 평가 : II. 이론식과 토크에 의한 지지력 예측 비교

30 June 2014. pp. 41-47

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Abstract

Various prediction methods for the bearing capacity of helical piles have been introduced with consideration of both the steel shaft and the helix plates attached to the shaft. In this paper, three representative methods, that is, individual bearing method, cylindrical shear method, and torque correlation method are discussed and compared to each other. The prediction methods were verified by comparing with a series of loading test results performed on moderate-size helical piles from the companion paper. As a result, the measured bearing capacity is greater than the bearing capacity predicted by the cylindrical shear method, but smaller than that of the individual bearing method. In addition, the bearing capacity predicted by the torque correlation method is in good agreement with the measured bearing capacity.

Keywords

Helical pile

Individual bearing method

Cylindrical shear method

Torque correlation method

Bearing capacity

헬리컬 파일은 나선형 원판이 부착된 철제 축과 나선형 원판이 모두 지지력을 발휘하기 때문에 지지력을 예측하는데 있어 기존의 일반적인 말뚝과는 다른 다양한 산정법이 적용되고 있다. 대표적으로 Individual bearing method, Cylindrical shear method, Torque correlation method가 사용되고 있다. 본 연구에서는 국내 지반에 시공된 중소구경 헬리컬 파일의 지지력을 예측하는데 있어 적절한 지지력 산정 방법을 검토하기 위해 연계논문의 현장 정재하시험에서 측정된 지지력과 3가지 방법으로 예측한 지지력을 비교 분석하였다. 비교 결과, 실측 지지력이 Individual bearing method와 Cylindrical shear method로 예측한 지지력의 최대값과 최소값 사이에 위치함을 확인하였으며, 상대적으로 Torque correlation method으로 예측한 결과가 실측지지력과 가장 유사함을 보였다.

References

1.Deardorff, D. (2007), “Torque Correlation Factors for Round Shaft Helical Piles”, In Proceedings of the 32nd Annual Con-ference of the Deep Foundation Institute, Colorado Springs, CO, pp.439-450.

2.Ha, T. S., Moon, H. R. and Moon, H. M. (2013), “An analysis of correlation between predicted and measured bearing capacity in Rotary(Helical) pile method”, Korean Geotechnical Society Conference.

3.Hoyt, R. M. and Clemence, S. P. (1989), “Uplift capacity of helical anchors in soil”, 12^th International Conference on Soil Mechanics and Foundation Engineering conducted in Rio de Janeiro, Brazil.

4.Lee, J., Lee, D., Kim, H-N and Choi, H. (2014), “Effect of configuration of shaft and helix plate on bearing capacity of moderate-size helical pile : I. Test-bed construction and field loading test”, Journal of the Korean Geosynthetics Society, under review.

5.Livneh, B. and Naggar, M. H. (2008), “Axial testing and numerical modeling of square shaft helical piles under compressive and tensile loading”, Canadian Geotechnical Journal, Vol. 45, Issue 8, pp.1142-1155.

6.Meyerhof, G. G. (1951), “The Ultimate Bearing Capacity of Foundations.” Geotechnique, Vol. 2, No. 4, pp. 301-331.

7.Mooney, J. S., Adamczak S. Jr., and Clemence. S. P. (1985), “Uplift Capacity of Helix Anchors in Clay and Silt.” Uplift Behavior of Anchor Foundations in Soil, ASCE pp. 48-72.

8.Perko, H. A. (2009), Helical Piles, John Wiley & Sons, Inc., Hobojen, New Jersey, p.105-122.

9.Terzaghi, K. (1943) Theoretical Soil Mechanics. New York: John Wiley and Sons.

Information

Publisher :Korean Geosythetics Society
Publisher(Ko) :한국지반신소재학회
Journal Title :Journal of the Korean Geosynthetics Society
Journal Title(Ko) :한국지반신소재학회 논문집
Volume : 13
No :2
Pages :41-47
Received Date : 2014-05-08
Revised Date : 2014-06-04
Accepted Date : 2014-06-07
DOI :https://doi.org/10.12814/jkgss.2014.13.2.041

Journal of the Korean Geosynthetics Society ISSN:2508-2876(Print) 2287-9528(Online) 한국지반신소재학회 논문집

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