• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.255-262
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• 2000

Shaking table tests were peformed to evaluate the subgrade reaction of ground according to the build-up of pore water pressure. Model pile was installed in the sand ground. The acceleration of the model ground, the pore water pressure build-up and displacement of pile were recorded by measuring devices. Subgrade reaction approach based on Winker soil model was applied to obtain the modulus of the horizontal subgrade reaction. The results of analysis show that the reduction factor of the subgrade reaction due to pore pressure increase is about 1 and the horizontal subgrade reaction of liquefied ground is not influenced by the stiffness of pile, a ground acceleration and the intial ground density.

• 한국철도학회논문집
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• 제6권1호
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• pp.29-40
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• 2003

In this study, the three dimensional pile-soil dynamic interaction analysis of the railway bridge pile foundation was performed using SASSI 2000 program and the applicability of SASSI 2000 about an evaluation of the seismic stability of a pile foundation was examined. The numerical analysis was executed on the two site of actual construction and input properties such as the acceleration of bedrock were estimated by one dimensional seismic response analysis using the Pro-SHAKE. Consequently, all the piles of the subject of investigation showed that displacement occurred within a permitted limit and the shear force and moment largely occurred at the point where the soil stiffness varied rapidly.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.407-414
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• 1999

Sand drain as a vertical drainage is widely used in soft ground improvement. Recently, sand, the principal source of sand drain, is running out. A laboratory model test was carried out to utilize gravel as a substitute for sand. Though which the characteristics of gravel are compared to those of sand for engineering purpose. According to the test, the settlement was found to be smaller in gravel drain than in sand drain. The increase in bearing capacity by gravel rile explains the result. The clogging effect was not found in gravel column. As a result, it is assumed that gravel is relatively acceptable as a drainage material. Gravel material seems better than sand material in bearing capacity and it is found that bearing capacity is larger when gravel is used as compaction pile than as drain from in-situ test on bearing capacity. Increase of bearing capacity with gravel pile means an effect of composite ground by stiffness of gravel material. It can lie supposed to use gravel pile instead of sand pile in view of consolidation effect and bearing capacity.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.147-152
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• 2003

The purpose of this paper is to develope an understanding of fundamental mechanism of shear behaviour between granite and concrete interfaces. The interface of pile socketed in rock can be modeled in laboratory tests by resolving the axisymmetric pile situation into the two dimensional situation under CNS(constant normal stiffness) direct shear condition. In this paper, the granite core samples were used to simulate the interface condition of piles socketed In granite. The samples were prepared in the laboratory to simulate field condition, roughness(angle, height), stress boundary condition, and then tested by CNS direct shear tests. This paper gives some points about shearing behaviour of socket piles into domestic granite through the analysis of CNS tests results.

• 한국지반공학회논문집
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• 제18권4호
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• pp.285-294
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• 2002

연약지반상에 제방 성토시 예상되는 연약지반의 측방유동을 적극 억지할 수 있는 성토지지말뚝공법은 말뚝두부에 캡을 설치하는 형태에 따라 크게 말뚝슬래브공법, 캡보말뚝공법 및 단독캡말뚝공법으로 구분할 수 있다. 이들 공법중 캡보말뚝공법 및 단독캡말뚝공법에서는 성토지지말뚝과 지반간의 상대적인 강성차이로 인해 성토지반 속에 지반아치가 발생하게 되고, 대부분의 성토하중은 발달된 지반아치를 통해 말뚝으로 전달된다. 두 공법에서 발생되는 지반아치의 차이는 그 형태가 캡보말뚝공법의 경우 터널의 형태와 유사하게 2차원적이고, 단독캡말뚝공법에서는 돔의 형태와 유사하게 3차원적이라는 것이다. 따라서 이 두 경우의 지반아치로 인한 성토지지말뚝의 하중분담효과에 관한 이론식을 각각 유도 제안하여 비교하였으며, 두 이론식의 타당성을 입증하기 위한 일련의 모형실험을 수행하였다.

• Interaction and multiscale mechanics
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• 제3권1호
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• pp.55-79
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• 2010

The effect of soil-structure interaction on a single-storey, two-bay space frame resting on a pile group embedded in the cohesive soil (clay) with flexible cap is examined in this paper. For this purpose, a more rational approach is resorted to using the finite element analysis with realistic assumptions. Initially, a 3-D FEA is carried out independently for the frame on the premise of fixed column bases in which members of the superstructure are discretized using the 20-node isoparametric continuum elements. Later, a model is worked out separately for the pile foundation, by using the beam elements, plate elements and spring elements to model the pile, pile cap and soil, respectively. The stiffness obtained for the foundation is used in the interaction analysis of the frame to quantify the effect of soil-structure interaction on the response of the superstructure. In the parametric study using the substructure approach (uncoupled analysis), the effects of pile spacing, pile configuration, and pile diameter of the pile group on the response of superstructure are evaluated. The responses of the superstructure considered include the displacement at top of the frame and moments in the columns. The effect of soil-structure interaction is found to be quite significant for the type of foundation considered in the study. Fair agreement is observed between the results obtained herein using the simplified models for the pile foundation and those existing in the literature based on a complete three dimensional analysis of the building frame - pile foundation - soil system.

• 한국지반공학회논문집
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• 제26권12호
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• pp.31-40
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• 2010

본 연구에서는 수직 및 수평하중을 받는 말뚝기초의 두부구속조건(고정단, 힌지단)에 따른 3차원 수치해석을 수행하였다. 수평하중과 수직하중 작용 시 말뚝과 기초의 강결합(고정단)이 힌지결합에 비하여 말뚝두부에서 횡방향 강성 및 단면 발생모멘트(휨모멘트)가 크게 나타나고 전면기초(raft)에서 발생하는 전단력도 크게 나타남을 알 수 있었다. 따라서 말뚝의 두부구속조건이 말뚝기초 전체의 거동에 지대한 영향을 미치는 것을 알 수 있었으며, 힌지결합이 강결합과 비교하여 전면기초의 두께 및 말뚝의 철근 배근량을 감소시킬 수 있기 때문에 허용변위를 만족하는 선에서 경제적인 말뚝기초의 설계가 가능할 것으로 판단된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.173-183
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• 2010

Numerical analysis using a three dimensional finite element program(ABAQUS) is a powerful method which can evaluate the soil-pile-structure interaction under the dynamic loading and reduce the computation time significantly, but has not be widely used because modeling a soil-pile system and setting the parameter for the entire model are difficult and a three dimensional finite element program is not user friendly. However, a three dimensional finite element program is expected to be widely used because of advance in research of modeling technique and development of the modeling and visualization. In this study, ABAQUS is used to simulate the 1g shaking table model pile test, and the numerical results are compared with the 1g shaking table test results. The application about the soil stiffness and boundary condition change is estimated and then parametric study for various input acceleration amplitudes, various input frequencies, and various surcharge is carried out.

• 한국지반공학회논문집
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• 제32권12호
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• pp.15-22
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• 2016

본 연구에서는 Strain wedge 해석모델을 이용하여 수평하중이 작용하는 단말뚝의 극한수평저항력 산정식을 제안하였다. 저항특성은 쐐기 후면부의 수평저항토압, 쐐기 측면부의 전단저항, 그리고 말뚝과 지반의 마찰저항으로 구분하였고, 이들의 합으로써 극한수평저항력을 산정하였다. 제안된 식을 기존의 쐐기 이론과 현장실험, 유한차분법과비교 분석하였다. 그 결과 제안식의 값이 기존의 쐐기 이론과 1.03%, 현장실험과는 0.40~3.32%, 유한차분법과는 6.02%의 차이를 보였다.

• 한국지반공학회논문집
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• 제26권11호
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• pp.39-46
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• 2010

본 연구에서는 Strain Wedge 해석모델을 이용하여 수평하중이 작용하는 단독말뚝의 수평저항력 산출식을 제시하였고, 이를 모형실험, 현장 실험의 결과와 기존의 문헌에서 제시된 수평저항력 산정식과 비교 분석하였다. 그 결과 모형 실험의 시험 결과보다 조금 작게 나타났고, 현장 재하실험 결과와는 말뚝 두부의 변위가 작을 경우 상당히 잘 일치하고 있으나, 말뚝 두부의 변위가 증가할 수록 결과 값의 차가 조금씩 발생하였다. 그리고 기존의 산출식과 비교 검토한 결과 유한차분법과 잘 일치하였다.