Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
권호 표지

Behaviors of Pile Croup Installed Near Inclined Ground

경사지반에 인접하여 설치된 무리말뚝의 거동연구

  • Published : 2003.06.01
Download PDF
⟨ Previous Next ⟩

Abstract

Many transmission towers, high-rise buildings and bridges are constructed near steep slopes and are supported by large-diameter piles. These structures may be subjected to large lateral loads, such as violent winds and earthquakes. Widely used types of foundations for these structures are pier foundations, which have large-diameters with high stiffness. The behavior of a pier foundation subjected to lateral loads is similar to that of a short rigid pile because both elements seem to fail by rotation developing passive resistance on opposite faces above and below the rotation point, unlike the behavior of a long flexible pile. This paper describes the results of several numerical studies performed with a three-dimensional finite element method (FEM) of model tests of a laterally loaded short pile located near slopes, respectively. In this paper, the results of model tests of single piles and pile groups subjected to lateral loading, in homogeneous sand with 30$^{\circ}$ slopes and horizontal ground were analyzed by the 3-D FE analyses. The pile was assumed to be linearly elastic. The sand was assumed to have non-associative characteristics, following the MC-DP model. The failure criterion is governed by the Mohr-Coulomb equation and the plastic potential is given by the Drucker-Prager equation. The main purpose of this paper is the validation of the 3-D elasto-plastic FEM by comparisons with the experimental data.

사면을 포함한 경사지에 설치된 송전탑, 교각, 고층빌딩 등을 지지하는 말뚝은 풍하중, 지진, 차량 등에 의한 수평하중을 고려하여 설계되어야 한다. 이러한 사면이나 경사지에 설치된 수평하중을 받는 말뚝은 편평한 지반에 비하여, 수평지지력이 감소하기 때문이다. 그러므로 이러한 구조물은 일반적으로 강성이 높고, 대구경의 기초인 피어기초가 사용된다. 수평하중을 받는 피어기초는 일반적으로 장대말뚝과 다른 거동을 한다. 즉, 수평하중에 의하여 말뚝 자체의 회전이 발생하고, 그 회전의 중심점 상부의 사면측의 수동토압에 의존하여 지반파괴가 발생한다는 측면에서 짧은 강성 말뚝과 유사한 거동을 한다. 본 논문은 모래사면의 언덕 근처에 설치된 짧은 말뚝의 수평하중의 영향에 대한 실험 및 수치해석 결과를 포함한다. 대부분을 모형실험과 3차원 탄소성 유한요소해석의 비교, 결과를 기술하였다. 먼저, 사면 언덕에서 모형말뚝까지의 거리를 3종류로 구분하여 단항의 모형실험과 군항말뚝의 수평하중 특성을 파악하기 위하여 수평지반과 사면지반(경사 30$^{\circ}$)에 대하여 말뚝중심간의 거리를 각2종류로 모형실험을 실시하였다. 동시에 3차원 탄소성 유한요소법에 의한 수치해석을 통하여 모형실험의 결과와의 비교를 시도하였다. 사용된 모래지반은 배수조건하에서 삼축압축실험으로 재현하였다. 3차원 탄소성 유한요소해석에서 완전탄소성모델의 파괴기준은 Mohr-Coulomb식, 소성 포텐셜은 Drucker-Prage식을 이용한 MC-DP모델을 적용하였다. 연구결과, 3차원탄소성 유한요소법이 사질토 지반에 설치된 짧은 말뚝의 수평거동을 파악하는데 유효하다는 것을 확인하였다.

Keywords

References

  1. Geotechnique v.31 The response of flexible piles to lateral loading Randolph,M.F. https://doi.org/10.1680/geot.1981.31.2.247
  2. Proc. of the 15th Int. Symp. On Numerical Models in Geomechanics 3-D finite element analyses of the ultimate behavior of laterally loaded cast-in-place concrete piles Kimura,M.;Adachi,T.;Kamei,H.;Zhang,F.
  3. J. Struct. Constr. Eng. AIJ v.478 Behaviour of lateral loaded pile near a cliff Chatani,F.;Nishiyama,T.
  4. Computers and Geotechnics v.10 no.1 3-dimensional finite element model of laterally loaded piles Brown,D.A.;Shiethree,C.F. https://doi.org/10.1016/0266-352X(90)90008-J
  5. Numerical Methods in Offshore Piling Application of a numerical produre for laterally loaded structures Desai,C.S.;Kuppusamy,T.
  6. Soils and Foundations v.32 3-D elasto-plastic finite element analyses of pile foundations subjected to lateral loading Wakai,A.;Gose,S.;Ugai,K.
  7. Computer and Geotechnics v.25 Three-dimensional finite element studies of the moment-carrying capacity of short pier foundations in cohesionless soil Laman,M.;King,G.J.W.;Dikin,E.A. https://doi.org/10.1016/S0266-352X(99)00019-1
  8. Danish Geotechnical Institute, Bulletin v.12 The ultimate resistance of rigid piles against transversal forces Brinch Hansen,J.
  9. J. of SMFE Div. v.90 Lateral resistance of piles of cohesionless soils Broms,B.B.
  10. Proc. 5th European Conf. on SMFE v.3 Ultimate lateral resistance of a rigid pile in cohesionless soil Petrasovits,G.;Award,A.
  11. Can. Geotech. J. v.18 Lateral resistance and deflection of rigid wall and piles in layered soils Meyerhof,G.G.;Mathur,S.K.;Valsangkar,A.J. https://doi.org/10.1139/t81-015
  12. Soils and Foundations v.15 no.4 Methods to estimate lateral force acting on stabilizing piles Ito,T.;Matsui,T. https://doi.org/10.3208/sandf1972.15.4_43
  13. Soils and Foundations v.40 no.1 Numerical analysis of the stability of a slope reinforced with piles Cai,F.;Ugai,K. https://doi.org/10.3208/sandf.40.73
  14. Principle of Soil mechanics(first revision) Deformation and stability analysis by finite element method Tankak,T.
  15. ASCE J. of Geotech. Eng. v.118 no.6 Analysis of laterally loaded shafts in rock Cater,J.P.;Kulhawy,F.H. https://doi.org/10.1061/(ASCE)0733-9410(1992)118:6(839)
  16. ASCE J. of SMFE Div. v.86 no.5 Generalized solutions for laterally loaded piles Matlock,H.;Reese,L.C.
  17. Can. Geotech. J. v.20 Ultimate capacity of rigid single piles under inclined loads in sand Chari,T.R.;Meyerhof,G.G. https://doi.org/10.1139/t83-091
  18. Geotechnique v.5 Evaluation of coefficients of subgrade reaction Terzaghi,K. https://doi.org/10.1680/geot.1955.5.4.297
  19. Soils and Foundations v.35 no.4 Three-dimensional limit equilibrium and finite element:a comparison of results Ugai,K.;Leshchinsky,D. https://doi.org/10.3208/sandf.35.4_1
  20. Introduction to strength of soils and failure of ground(third revision) Relationships between the stress and strain increments Tatsuoka,F.