Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Buckling Behaviors of Tapered Piles

테이퍼 말뚝의 좌굴 거동

  • Received : 2018.12.11
  • Accepted : 2019.02.21
  • Published : 2019.02.28
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Abstract

In this study, an analytical model is proposed to estimate the buckling responses of tapered piles. The governing differential equation of the soil-pile system considering the tapering and side friction of the pile and the soil nonhomogeneity is derived, which is numerically integrated by the Runge-Kutta method and then the eigenvalue of bucking load is determined by Regula-Falsi algorithm. For a cylindrical pile, the results obtained from this study are found to compare well with those reported in literature. Illustrative examples for buckling load and stress as well as buckled shape are provided to investigate the effects of dimensionless parameters related to the soil-pile system.

본 논문에서는 테이퍼 말뚝의 좌굴 거동을 평가할 수 있는 해석모델을 제안하였다. 말뚝의 변단면과 주면마찰, 지반의 비균질성을 고려하는 지반-말뚝 시스템의 좌굴을 지배하는 미분방정식을 유도하였다. 이 지배방정식을 Runge-Kutta 법을 이용하여 직접 수치 적분하였고, 미분방정식의 고유치인 좌굴하중은 Regula-Falsi 법을 이용하여 산정하였다. 원통형 말뚝에 대한 문헌값과 이 연구의 좌굴하중을 비교하여 연구의 타당성을 검증하였고, 지반-말뚝에 관련된 무차원변수가 좌굴하중, 좌굴모드, 좌굴응력에 미치는 영향을 분석하였다.

Keywords

GJBGC4_2019_v35n2_19_f0002.png 이미지

Fig. 3. Comparison of obtained and existing solution for cylindrical piles with different boundary conditions: (a) free-free, (b) free-pinned, and (c) free-fixed

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Fig. 4. Variation of b with ar

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Fig. 5. Variation of b with ak

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Fig. 6. Variation of b with af

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Fig. 7. Variations of b with (a) γ and (b) α

GJBGC4_2019_v35n2_19_f0007.png 이미지

Fig. 8. Variation of b with β

GJBGC4_2019_v35n2_19_f0008.png 이미지

Fig. 9. Buckling modes of tapered friction piles: (a) free-free, (b) free-pinned, and (c) free-fixed

GJBGC4_2019_v35n2_19_f0009.png 이미지

Fig. 10. ζb profiles along ξ : (a) free-free, (b) free-pinned, and (c) free-fixed

GJBGC4_2019_v35n2_19_f0010.png 이미지

Fig. 1. Notations for soil-pile system: variations of (a) pile radius, (b) coefficient of subgrade reaction, and (c) unit side-friction resistance

GJBGC4_2019_v35n2_19_f0011.png 이미지

Fig. 2. (a) Idealization of a bucked taper pile embedded in elastic foundation supported by friction forces, and (b) defection and forces of pile segment

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