Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
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A Study on the Correlation Evaluation of Confining Pressure and Pile-Soil Interface Strength Reduction Factor Using Numerical Analysis

수치해석에 의한 지중 구속압과 말뚝-지반 경계면 강도감소계수 관계 분석

  • Tae-Gyeom Lee (School of Civil Engineering, Chung-Ang Univ.) ;
  • Jung-Geun Han (Department of Civil&Environmental Engineering, Chung-Ang Univ., Intelligent Energy&Industry, Chung-Ang Univ.) ;
  • Gigwon Hong (Dept. of Urban Infra Engineering, Halla University) ;
  • Seung-Kyong You (Dept. of Civil Engineering, Myongji College)
  • Received : 2024.02.19
  • Accepted : 2024.02.27
  • Published : 2024.03.30
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Abstract

In order to evaluate the relationship between the ground confining pressure and the shear characteristics of the pile-soil interface, this study described the comparative results of the existing experimental results and the FEA results using the strength reduction factor. The strength reduction factor was applied to simulate the shear behavior of the pile-soil interface in finite element analysis(FEA). The analysis results showed that the maximum pullout resistance decreased due to the influence of low confining pressure, as the fines content increased. This trend was similar to the previous experimental research, and this FEA model simulated with the interface strength reduction factor was evaluated as reasonable. The analysis results of the variation in the interface strength reduction factor clearly showed that the interface strength reduction factor clearly increased at a high fines content when the confining pressure was 50kPa. However, it was found that the increase rate was low when the confining pressure was 100kPa and 150kPa. Therefore, confining pressure and fines content need to be considered in FEA to evaluate the shear behavior of the pile-soil interface.

본 연구에서는 지중 구속압과 말뚝-지반 경계면 전단 특성의 관계를 평가하기 위하여 기존의 실험결과와 강도감소계수가 적용된 해석 결과를 비교하였다. 유한요소해석에서 말뚝-지반 경계면의 전단거동 모사는 강도감소계수를 적용하였다. 해석 결과, 세립분 함유율이 증가할수록 구속압의 영향이 낮아지면서 최대 인발저항력은 감소하였다. 이 해석결과의 경향은 기존 실험 결과와 유사한 것으로서, 경계면 강도감소계수가 적용된 유한요소해석 모델은 적절하게 모사된 것으로 평가되었다. 경계면 강도감소계수의 변화를 분석한 결과, 구속압 50kPa의 경우에는 세립분 함유율이 증가할수록 경계면 강도감소계수의 증가가 확연하게 나타난 반면에, 구속압이 100kPa 및 150kPa의 경우에는 그 증가폭이 낮은 것을 알 수 있었다. 따라서 말뚝-지반 경계면의 전단 거동을 평가하기 위한 유한요소해석은 구속압과 세립분 함유율이 고려되어야 한다.

Keywords

Acknowledgement

This research has been supported by the National Research Foundation of Korea(NRF) grant funded by Korea government(MSIT) (No. 2021R1F1A1052445).

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