• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.369-378
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• 2010

In this study, a computer program to predict the behavior of laterally loaded single pile and pile groups was developed by using a beam-column analysis in which the soils are modeled as nonlinear springs by a family of p-y curves for subgrade modulus. The special attention was given to the lateral displacement of a single pile and pile groups due to the soil condition and the cap rigidity. The analysis considering group effect was carried out for $2{\times}2$ and $3{\times}3$ pile groups with the pile spacing 3.0B, 4.0B and 5.0B. Based on the results obtained, it is found that the overall distributions of deflection, slope, moment, and shear force in a single pile give a reasonable results irrespective of cap connectivity conditions. It is also found that even though there are some deviations in deflection prediction compared with the observed ones, the prediction by present analysis simulates much better the general trend observed by the centrifuge tests than the numerical solution predicted by PIGLET.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.831-837
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• 2005

In this study, a computer program to predict the behavior of laterally loaded single pile and pile groups was developed by using a beam-column analysis in which the soils are modeled as nonlinear springs by a family of p-y curves for subgrade modulus. The special attention was given to the lateral displacement of a single pile and pile groups due to the soil condition and the cap rigidity. The analysis considering group effect was carried out for $2\;{\times}\;2\;and\;3\;{\times}\;3$ pile groups with the pile spacing 3.0B, 4.0B and 5.0B. Based on the results obtained, it is found that the overall distributions of deflection, slope, moment, and shear force in a single pile give a reasonable results irrespective of cap connectivity conditions. It is also found that even though there are some deviations in deflection prediction compared with the observed ones, the prediction by present analysis simulates much better the general trend observed by the centrifuge tests than the numerical solution predicted by PIGLET.

• Coupled systems mechanics
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• 제1권1호
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• pp.1-7
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• 2012

The problem of laterally loaded piles is particularly a complex soil-structure interaction problem. The flexural stresses developed due to the combined action of axial load and bending moment must be evaluated in a realistic and rational manner for safe and economical design of pile foundation. The paper reports the finite element analysis of pile groups. For this purpose simplified models along the lines similar to that suggested by Desai et al. (1981) are used for idealizing various elements of the foundation system. The pile is idealized one dimensional beam element, pile cap as two dimensional plate element and the soil as independent closely spaced linearly elastic springs. The analysis takes into consideration the effect of interaction between pile cap and soil underlying it. The pile group is considered to have been embedded in cohesive soil. The parametric study is carried out to examine the effect of pile spacing, pile diameter, number of piles and arrangement of pile on the responses of pile group. The responses considered include the displacement at top of pile group and bending moment in piles. The results obtained using the simplified approach of the F.E. analysis are further compared with the results of the complete 3-D F.E. analysis published earlier and fair agreement is observed in the either result.

• Geomechanics and Engineering
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• 제20권5호
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• pp.433-445
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• 2020

A new code, called PRaFULL (Piled Raft Foundation Under Lateral Load), was developed for the analysis of laterally loaded Combined Pile Raft Foundation (CPRF). The proposed code considers the contribution offered by the raft-soil contact and the interactions between all the CPRF system components. The nonlinear behaviour of the reinforced concrete pile and the soil are accounted. As shallower soil layers are of great relevance in the lateral response of a pile foundation, PRaFULL includes the possibility to consider layered soil profiles with appropriate properties. The shadowing effect on the ultimate soil pressure is accounted, when dealing with pile groups, as proposed by the Strain Wedge Model. PRaFULL BEM code obviously requires less computational resources compared to FEM (Finite Element Method) or FDM (Finite Difference Method) codes. The proposed code was validated in the linear elastic range by comparisons with the code APRAF (Analysis of Piled Raft Foundations). The reliability of the procedure to predict piled raft performance was then verified in nonlinear range by comparisons with both centrifuge tests and computer code PRAB.

• Interaction and multiscale mechanics
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• 제5권1호
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• pp.57-73
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• 2012

The paper presents the analysis of two groups of piles subjected to lateral loads incorporating the non-linear behaviour of soil. The finite element method is adopted for carrying out the parametric study of the pile groups. The pile is idealized as a one dimensional beam element, the pile cap as two dimensional plate elements and the soil as non-linear elastic springs using the p-y curves developed by Georgiadis et al. (1992). Two groups of piles, embedded in a cohesive soil, involving two and three piles in series and parallel arrangement thereof are considered. The response of the pile groups is found to be significantly affected by the parameters such as the spacing between the piles, the number of piles in a group and the orientation of the lateral load. The non-linear response of the system is, further, compared with the one by Chore et al. (2012) obtained by the analysis of a system to the present one, except that the soil is assumed to be linear elastic. From the comparison, it is observed that the non-linearity of soil is found to increase the top displacement of the pile group in the range of 66.4%-145.6%, while decreasing the fixed moments in the range of 2% to 20% and the positive moments in the range of 54% to 57%.

• 한국지반공학회논문집
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• 제19권3호
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• pp.53-64
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• 2003

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.