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2016 Vol.32, Issue 11 Preview Page
Evaluation of Allowable Bearing Capacity of 600 mm Diameter Preboring PHC Piles Using Dynamic Load Test

직경 600mm PHC 매입말뚝의 동재하시험을 통한 허용 지지력 평가

Gyu-Seong Woo1
,
Jong-Bae Park2*
,
Mi-Jeong Seo1
,
Jong-Sub Lee3
우 규성1
,
박 종배2*
,
서 미정1
,
이 종섭3
1Graduate Student, School of Civil, Environmental and Architectural Engrg., Korea Univ.
2Research Associate, Housing & Urban Research Institute, LHI
3Prof., School of Civil, Environmental and Architectural Engrg., Korea Univ.
1고려대학교 건축사회환경공학부 석사과정
2한국토지주택공사 토지주택연구원 수석연구원
3고려대학교 건축사회환경공학부 교수
*교신저자. *Corresponding Author. 
30 November 2016. pp. 61-72
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Abstract

For the construction of high-rise structures and the optimized foundation design, the use of the large-diameter PHC pile has increased. Especially, the use of the 600 mm diameter PHC pile has significantly increased. In this study, for the evaluation of the suitability of the current design practice, the 46 dynamic pile load tests, which were carried out in the 600 mm diameter preboring PHC pile, are analyzed. The end bearing capacity is obtained from the end of initial driving test and the shaft capacity is estimated from the restrike test. The allowable capacities estimated by the dynamic load test are compared with those based on the current design practice. The analyses show that the allowable end bearing capacity evaluated by the dynamic pile load test is greater than the design practice in most piles. The allowable shaft capacity, however, is smaller than the design practice in many piles. The higher end bearing capacity and the smaller shaft capacity may result from the improvement of the drilling equipment and the increase in the penetration depth. Thus, the portion of the end bearing capacity in the total capacity increases.

Keywords
Allowable bearing capacity
Dynamic load test
End bearing capacity
Preboring piles
Safety factor
Shaft capacity

구조물의 고층화가 진행됨과 동시에 효율적인 기초 설계를 위해 대구경 PHC 말뚝의 사용이 증가하고 있으며, 특히 600mm PHC 말뚝의 사용량이 급증하고 있다. 본 연구에서는 현재 사용되고 있는 설계법의 적정성을 평가하기 위하여, 직경 600mm PHC 매입말뚝에 대하여 수행된 46본의 동재하시험 결과를 분석하였다. 선단지지력은 초기항타시험의 결과를 이용하였으며 주면마찰력은 재항타시험 결과를 이용하여 각각의 허용지지력을 산정하였다. 동재하시험으로부터 산정된 허용지지력을 현재 사용되는 설계법으로 평가된 허용지지력과 비교하였다. 분석결과, 동재하시험으로 산정된 허용선단지지력은 대부분의 말뚝에서 설계기준보다 컸지만, 허용주면마찰력은 많은 말뚝에서 설계기준보다 작게 산정되었다. 이와 같은 큰 선단지지력과 작은 주면마찰력은 천공장비의 성능 향상 및 굴착 깊이의 증가 때문이며 이로 인해 전체지지력에서 선단지지력이 차지하는 비율이 높아졌기 때문이다.

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Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 32
  • No :11
  • Pages :61-72
  • Received Date : 2016-09-06
  • Revised Date : 2016-10-18
  • Accepted Date : 2016-11-16
  • DOI :https://doi.org/10.7843/kgs.2016.32.11.61
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