Analysis of the Load-Sharing Characteristics of a Piled Raft through Field Tests

Seok-Woo Hong; Young-Hoon Seo

doi:10.7843/kgs.2025.41.6.43

All Issue

2025 Vol.41, Issue 6 Preview Page Next Page

Analysis of the Load-Sharing Characteristics of a Piled Raft through Field Tests 현장시험 분석을 통한 말뚝지지 전면기초의 하중분담 특성

31 December 2025. pp. 43-52

PDF XML

Abstract

This study explored a construction method that enhances stability and economic efficiency for future large structures. Eight types of ground strength constants were calculated through analytical methods. The load-sharing rate was assessed using four pile diameters and five spacing ratios based on the calculated ground strength constants. In addition, the effects of cohesion force, internal friction angle, and deformation coefficient on ground deformation under load were investigated. An individual review was conducted, confirming that the deformation coefficient is the most significant parameter affecting ground subsidence. To accurately apply the deformation coefficient, which is critical for utilizing the formula proposed in this study for practical piled raft design, we directly compared the deformation coefficient values obtained from pressuremeter tests and large-scale plate bearing tests at the site. The results revealed a significant deviation in the range of 258%–618%. Establishing a clear theory through further tests on the correlation of the deformation coefficient between the pressuremeter and large-scale plate bearing tests could enable more precise design of piled rafts using the formula proposed in this study.

Keywords

Load sharing

Piled raft

Deformation coefficient

Large scale plate bearing test

Pressuremeter test

본 연구의 출발은 앞으로 지어질 대형 구조물에 대하여 지금보다 안정성을 확보하면서도 경제성이 확보되는 기초공법에 대한 고민에서 시작되었으며, 국내 대형 구조물 현장에서 실시된 대형평판재하시험을 실시한 네 곳의 자료와 유한요소해석을 통해 분석하여 8종류의 지반강도정수를 산정하였다. 산정된 지반강도정수의 조건으로 4가지 말뚝 직경과 5가지의 간격비로 하중분담률을 분석하였으며, 지반강도정수의 각 매개변수 점착력, 내부마찰각, 변형계수가 하중에 따른 지반의 변형에 미치는 영향을 파악하기 위해 개별적 검토를 실시하였으며, 검토 결과 지반의 침하에는 변형계수가 가장 큰 직접적인 매개변수임을 확인 할 수 있었다. 본 연구에서 제안한 식을 말뚝지지 전면기초의 실무 설계에 적용하기 위하여 가장 중요한 변수인 변형계수의 정확한 적용을 위해 사례 현장의 공내재하시험 변형계수 값과 대형평판재하시험 변형계수 값을 직접 비교한 결과를 정리하였으며, 그 결과가 258%~618%의 큰 편차가 있는 것으로 확인되었다. 대형평판재하시험과 공내재하시험과의 변형계수 상관관계에 대한 추가적인 시험을 통해 명확한 이론이 정립이 되면 본 연구에서 제안된 식을 이용한 말뚝지지 전면기초 설계를 보다 정확히 할 수 있을 것으로 판단된다.

References

Prakash, S. and Sharma, H. D. (1989), Pile Foundations in Engineering Practice, John Wiley & Sons, Inc., New York, p.768.

Katzenbach, B. and Reul, O. (1997), “Design and Performance of Piled Rafts”, 14th Intermational Conference on Soil Mechanics and Foundation Engineering, Hamburg, Vol.4, pp.2253-2256.

Randolph, M. F. (1983), “Design of Piled Raft Foundation”, Proceedings of the Intemational Symposium on Recent Development in Laboratory and Field Test and Analysis of Geotechnical Problems, Bangkok, pp.525-527.

Hong, S. W. (2009), “Analysis Method Considering the Ground Reinforcement Effect of Micropile by Field Loading Tests”, Journal of the Korean Geotechnical Society(KGS), Vol.25, No.1, pp.7-13. (in Korean)

Jeong, S.S. (2010), “The Unified Analysis of High-rise Building and Piled Raft Foundations”, Proceedings of Architectural Institute of Korea, Vol.30, No.1, pp.119-120.

Choi, K.J., Park, D.K., and Lee, J.H. (2012), “Load Sharing Analysis of Piled Rafts Based on Non-linear Load-Settlement Characteristics”, Journal of the Korean Geotechnical Society(KGS), Vol.28, No.11, pp.33-40. (in Korean)

10.7843/kgs.2012.28.11.33

Lee, J.H., Cho, H.Y., You, K.H., and Jeong, S.S. (2012), “A Study on the Ultimate Point Resistance of Rock Socketed Drilled Shafts Using FLAC3D and UDEC”, Journal of the Korean Geotechnical Society(KGS), Vol.28, No.1, pp.29-39. (in Korean)

10.7843/kgs.2012.28.1.29

Seo, Y.H. (2021), A Study on the Load Sharing Characteristics of the Piled Raft, PhD thesis, Dongeui University.

Hong, S. W. and Hwang, G. B. (2019), “A Study on Characteristics of the Unit Skin Friction Using the Wall Roughness in the Soft Rock”, Journal of the Korean Geotechnical Society(KGS), Vol.35, No.12, pp.7-13, https://doi.org/10.7843/kgs.2019.35.12.7. (in Korean)

10.7843/kgs.2019.35.12.7

Information

Publisher :The Korean Geotechnical Society
Publisher(Ko) :한국지반공학회
Journal Title :Journal of the Korean Geotechnical Society
Journal Title(Ko) :한국지반공학회 논문집
Volume : 41
No :6
Pages :43-52
Received Date : 2025-09-10
Revised Date : 2025-10-01
Accepted Date : 2025-10-01
DOI :https://doi.org/10.7843/kgs.2025.41.6.43

Journal of the Korean Geotechnical Society ISSN:1229-2427(Print) 2288-646X(Online) 한국지반공학회 논문집

All Issue