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2017 Vol.16, Issue 4
Analysis of Axial Capacity and Constructability of Helical Pile with Inner Cone Penetration

내부 콘 항타를 적용한 헬리컬 파일의 지지력 및 시공성 분석

Jun-Ho Lee1
,
Kicheol Lee1
,
Dongwook Kim2*
이 준호1
,
이 기철1
,
김 동욱2*
1Member, Graduate Student, Dept of Civil and Environmental Engineering, Incheon National Univ.
2Member, Associate Professor, Dept of Civil and Environmental Engineering, Incheon National Univ.
*교신저자. *Corresponding Author. 
30 December 2017. pp. 1-11
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Abstract

In this study, 1/6 small-scale model tests of helical piles were conducted to evaluate their installation time and ultimate capacities. Model sand layers were constructed using sand pluviating method to produce uniform soil relative density. For installation of different helical piles varying locations (vertical center-to-center spacings of 50 mm and 150 mm) of helix plates, two different rotation speeds of 15 rpm and 30 rpm were implemented. Cone penetration equipment was installed within the hallow section of the helical pile to increase ultimate capacity of helical pile and to evaluate soil properties of plugged soils and soils below pile tip after installation of the piles. Based on the test results, the most fasted installation was possible under the condition of “rotation speed of 30 rpm and center-to-center spacing of 50 mm”, and the highest ultimate capacity was mobilized under the condition of “rotation speed of 30 rpm and center-to-center spacing of 150 mm with cone penetration implementation.”

Keywords
Helical pile
Inner cone penetration
Sand pluviator
Ultimate load
Installation time

본 연구에서는 헬리컬 파일의 관입시간과 극한하중에 관한 연구를 진행하고자 1/6 축소모형 실험을 진행하였다. 균질한 상대밀 도의 사질토 지반을 형성하기 위하여 강사법을 사용하였다. 실험 조건으로 헬리컬 파일의 나선형 원판(heilx plate) 간격을 50mm와 150mm 두 Type으로 제작하였고, 헬리컬 파일의 회전관입 시 회전속도를 15rpm과 30rpm으로 진행하였다. 관입 완료된 헬리컬 파일에 콘 장비를 항타하여 관입하였다. 콘 장비 관입으로 헬리컬 파일의 극한하중 증가와 폐색의 정도를 확인 할 수 있었다. 위의 실험 결과를 토대로 헬리컬 파일의 관입시간은 “회전속도 30rpm-나선형 원판 간격 50mm”에서 단축 되었고, 극한하중은“회전속도 30rpm-나선형 원판 간격 150mm-콘 장비 유”인 조건에서 높은 극한하중을 보였다.

References
1
Davisson, M. T. (1975), “Piles Load Capacity”, Proc. ASCE Conf. Design Construction and Performance of Deep Foundation, University of California, Berkeley.
2
Franke, E. (1989), “Co-report to Discussion, Session 13: large-diameter piles”, 12th Int. Conf. Soil Mechanics and Foundation Engineering, Rio de Janeiro.
3
Japanese Industrial Standards (JIS), (2009), Test method for minimum and maximum densities of sands, A 1224, Japanese Industrial Standards, Tokyo, Japanese.
4
Jeong, S. S. and Ko, J. Y. (2016), “Influence Factors on the Degree of Soil Plugging for Open-Ended Piles”, Journal of The Korean Geotechnical Society, Vol.32, No.5, pp.27-36.
5
Kim, S. R. and Chung, S. G. (2006), “Determination of True Resistance from Load Transfer Test Performed on a PHC Pile”, Journal of The Korean Geotechnical Society, Vol.22, No.11, pp.113-122.
6
Kindel, C. E. (1977), “Mechanism of Soil Resistance for Driven Pipe Piles,” The 4th Annual Symposium of the Waterway Port, Coastal and Ocean Division of ASCE, Long Beach, pp. 251-268.
7
Korean Agency for Technology and Standards (KATS), (2002), The method for particle size distribution of soils, F 2302, Korean Agency for Technology and Standards, Chung-cheongbuk-do, Korea.
8
Korean Agency for Technology and Standards (KATS), (2007), Testing method for direct shear test of soils under consolidated drained conditions, F 2343, Korean Agency for Technology and Standards, Chungcheongbuk-do, Korea.
9
Korean Agency for Technology and Standards (KATS), (2016), Standard test method for density of soil particles, F 2308, Korean Agency for Technology and Standards, Chungcheongbuk-do, Korea.
10
Lee, D. S., Na, K. U., Lee, W. J., Kim, H. N., and Choi, H. S. (2014), “Applicability of Bi-directional Load Test for Evaluating Bearing Capacity of Helical Piles”, Journal of Korean Geosynthetics Society, Vol.13, No.4, pp.77-85.
11
Lee, J. H., Ji, S. B., Lee, K. C., and Kim, D. W. (2017), “Analysis of Bearing Capacity Improvement Effect of Inner Cone Penetration Equiped Open-Ended Steel Pipe Pile”, Journal of Korean Geosynthetics Society, Vol.16, No.2, pp. 67-77.
12
Mooney, J. S., Stephan, A., and Samuel, P. C. (1985), “Uplift Capacity of Helical Anchors in Caly and Silt”, ASCE pp. 48-72.
13
Na, K. U., Lee, D. S., Lee, H. G., and Choi, H. S. (2015), “Optimization for Configuration and Material Cost of Helical Pile Using Harmony Search Algorithm”, Journal of the Korean Society of Civil Engineers, Vol.35, No.2, pp.377-386.
14
Narasimha, R. S., Prasad, Y. V. S. N., and Dinakara Shetty, M. (1991), “ The Behavior of Model Screw Piles in Cohesive soils, soils and Foundations”, Journal of the Japanese Society of Soil Mechanics and Foundation Engineering, Vol.31, No.2, pp.35-50.
15
Parkin, A. K., Holden, J., Aamot, K., Last, N., and Lunne, T. (1980), Laboratory Investigations of CPT’s in Sand, Report 52108-9, NGI, Oslo.
16
Perko, H. A. (2009), Helical Piles, John Wiley & Sons, Inc, Hobojen, New Jersey.
17
Sakr, M. (2009), “Performance of helical piles in oil sand”, Journal of the Canadian Geotechnical, Vol.46, pp.1046-1061.
18
Sowers, G. B. and Sowers, G. F. (1970). Introductory Soil Mechanics and Foundations, 3rd Edition, Collier Macmillan Ltd.
19
Terzaghi, K. (1943), “Theoretical soil mechanics”, New York: Wiley.
Information
  • Publisher :Korean Geosythetics Society
  • Publisher(Ko) :한국지반신소재학회
  • Journal Title :Journal of the Korean Geosynthetics Society
  • Journal Title(Ko) :한국지반신소재학회 논문집
  • Volume : 16
  • No :4
  • Pages :1-11
  • Received Date : 2017-09-29
  • Accepted Date : 2017-10-14
  • DOI :https://doi.org/10.12814/jkgss.2017.16.4.001
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