• Title/Summary/Keyword: foundation settlement

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얕은 기초에서의 침하문제 (Settlement Problems in Shallow Foundations)

  • 이상덕
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 기초기술위원회 워크샵
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    • pp.53-80
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    • 2002
  • Settlement in the Shallow Foundation are presented. Various practical methods to calculate immediate settlement, consolidation settlement, and secondary compression of the compressive soils under the shallow foundation are summerized. Especially the critical depth for settlement calculation, the contact pressure, the allowable settlement of the shallow foundation are recommended.

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연약지반에서 날개벽 기초의 침하량 산정 (Settlement Behavior of Wing-wall type Foundation on Soft Grounds)

  • 장시경;이광열;황재홍;정진교
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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    • pp.1164-1169
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    • 2009
  • Piled raft foundation is commonly used for structure on deep soft soil deposit rather than end bearing piles to control differential settlement. However, it is still expensive for light weight structures. Wing-wall type foundation has been successfully applied to reduce average settlement for light weight structure. This study will further investigate this type of foundation using bench scale experiments on clay and sand. Numerical analysis and approach method are used to verify load settlement curve of wing-wall foundation on experimentally study. Furthermore, normalized settlement curves are applied to define prediction of settlement on wing-wall foundation. In the result settlement on wing-wall foundation can be effectively done by increasing the length of wall instead of number of walls and equation for calculating average settlement can be derived using normalized load settlement curve.

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팽이기초공법(Top-Base Method)의 하중-침하량 분석 (Load-Settlement Characteristics of Concrete TOP-BASE Foundation on Soft Ground)

  • 김재영;정상섬;이재환
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 춘계 학술발표회
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    • pp.210-221
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    • 2009
  • A new foundation type which is called Top-Base method has been used frequently in engineering practices in Korea. In this study, the settlement behavior of concrete Top-Base foundation on soft ground is investigated since the consolidation settlement of the embedding depth and the effect of footing dimensions are not included in current Korean criterion (2007). To obtain detailed information, the model tests of the Top-Base foundation are performed using the PLAXIS 3D finite element analysis. It is shown that in-situ measurements and finite element analysis of the behavior of foundations indicate that consolidation settlement is reduced up and bearing capacity of the foundation increases up to 50%~100%, compared to the primary non-treated ground. Based on this study, it is found that the Top-Base foundation prevents the lateral deformation of soft ground and reduces its negative dilatancy to the surface settlement, and that the foundation creates rather uniform stress distribution under it to increase its bearing capacity. It is also found that the total settlement of Top-Base foundation was highly dependent on the consolidation settlement and footing configurations.

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경부고속철도 콘크리트궤도 토공 및 원지반 침하 (I) (Settlement of Embankment and Foundation for Concrete Track of Gyungbu High Speed Railroad)

  • 양신추;문재석;이현정;강대웅;김대상
    • 한국철도학회논문집
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    • 제9권6호
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    • pp.644-651
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    • 2006
  • An application of concrete track is being actively processed for the construction of Korean railroad. The concrete track has an advantage to decrease the maintenance ire, but is very difficult system to maintain after earthwork settlement occurred. Therefore, the management and control of embankment and foundation settlement is very important for the successful concrete track construction. We expect that the main part of the settlement of the concrete track is the one of embankment and foundation supporting it. Settlements vulnerable to the concrete track among the causes of lots of settlements are primary consolidation and secondary compression settlement of foundation, creep settlement of embankment, settlement caused by train load, and unequal settlement resulting from the difference of embankment material and construction process. This paper investigated the settlement causes to make badly effects on the concrete track and also evaluated the settlement with field tests and numerical analysis.

연약지반에서 경량구조물 기초의 침하거동에 관한 연구 (A Study on The Settlement Behavior of Foundations for Light-weight Structures on Clay Deposits)

  • 이광열;정진교;윤성태
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2007년 가을학술발표회
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    • pp.692-700
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    • 2007
  • There are several types of foundations for light-weight structures, such as low story buildings, on soft clay deposits. Those foundations, such as piled raft, compensated foundation, mat foundation, floating foundation are commonly used rather then end-bearing piles to get more benefits on the construction and cost savings. In this study, settlement behaviors are computed and compared for several types of foundations on soft clay deposits. Also, theoretical expressions of parameters for piled raft system were provided with co-relations for design purposes. The predictions of settlements of piled rafts foundation are proposed based on the pile dimensions and design loads. From this study, the piled raft foundations is more benefits for reducing the settlement of clay deposits, and it is found that the piled raft system is applicable and effective on thick clay deposits, and that differential settlements of the foundation should be managed by designing the configuration of pile lengths.

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유한요소법에 의한 얕은 기초의 지지력 및 침하 특성 연구 (A Study of Bearing Capacity and Settlement of Shallow Foundation by FEM)

  • 박종수;박춘식;장정욱
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2006년도 춘계 학술발표회 논문집
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    • pp.1312-1319
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    • 2006
  • This thesis studied the scale effects on bearing capacity and settlement characteristics by using FEM. The conclusions of the study are as follows. 1) For sandy soil, the bearing capacity ratio increased in the form of logarithm as the foundation width increased. Hence application of static mechanic theory results in overestimation of the bearing capacity when the bearing capacity should be derived from plate loading test results. 2) In clayey soil, the characteristics of the bearing capacity associated with foundation width met Terzaghi's bearing capacity theory. 3) In sandy soil, the settlement ratio increased non-linearly as foundation width increased. However, in clayey soil, the settlement ratio increased linearly. 4) In ordinary soil, the foundation width - settlement ratio turned out to be close to that of sandy soil.

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Assessment the effect of pile intervals on settlement and bending moment raft analysis of piled raft foundations

  • Ghiasi, Vahed;Moradi, Mobin
    • Geomechanics and Engineering
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    • 제16권2호
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    • pp.187-194
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    • 2018
  • Application the pile group foundation to reduce overall settlement of the foundation and also avoid a very fruitful settlement of foundations, inconsistent was carried out. In such a case, in event that the Foundation, not as a mere pile group, which as a system consisting of a broad foundation with pile Group, economic design criteria will be provided in spite of high safety. A new approach in the design of the Foundation can be introduced as the piles are just a tool to improve the parameters of soil hardness; that it can work with detachable piles from raft. Centralized arrangement of piles as the most optimal layout of piles in reducing inconsistent settlement, which is the lowest value of resulting layout in this differential settlement. Using the combination of piles connected and disconnected to form the raft, bending moment created in the raft is reduced. It also concentrated arrangements have greatest effect in reducing amount of moment applied to the raft.

Application of artificial neural networks in settlement prediction of shallow foundations on sandy soils

  • Luat, Nguyen-Vu;Lee, Kihak;Thai, Duc-Kien
    • Geomechanics and Engineering
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    • 제20권5호
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    • pp.385-397
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    • 2020
  • This paper presents an application of artificial neural networks (ANNs) in settlement prediction of a foundation on sandy soil. In order to train the ANN model, a wide experimental database about settlement of foundations acquired from available literatures was collected. The data used in the ANNs model were arranged using the following five-input parameters that covered both geometrical foundation and sandy soil properties: breadth of foundation B, length to width L/B, embedment ratio Df/B, foundation net applied pressure qnet, and average SPT blow count N. The backpropagation algorithm was implemented to develop an explicit predicting formulation. The settlement results are compared with the results of previous studies. The accuracy of the proposed formula proves that the ANNs method has a huge potential for predicting the settlement of foundations on sandy soils.

Settlement analysis of viscoelastic foundation under vertical line load using a fractional Kelvin-Voigt model

  • Zhu, Hong-Hu;Liu, Lin-Chao;Pei, Hua-Fu;Shi, Bin
    • Geomechanics and Engineering
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    • 제4권1호
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    • pp.67-78
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    • 2012
  • Soil foundations exhibit significant creeping deformation, which may result in excessive settlement and failure of superstructures. Based on the theory of viscoelasticity and fractional calculus, a fractional Kelvin-Voigt model is proposed to account for the time-dependent behavior of soil foundation under vertical line load. Analytical solution of settlements in the foundation was derived using Laplace transforms. The influence of the model parameters on the time-dependent settlement is studied through a parametric study. Results indicate that the settlement-time relationship can be accurately captured by varying values of the fractional order of differential operator and the coefficient of viscosity. In comparison with the classical Kelvin-Voigt model, the fractional model can provide a more accurate prediction of long-term settlements of soil foundation. The determination of influential distance also affects the calculation of settlements.

폐콘크리트 재생잔골재의 하수관거 모래기초 적용에 따른 침하 거동 (Settlement of Fine Recycled-concrete Aggregates Foundation under Sewage Conduit System)

  • 오재일;안남규;이주영
    • 대한환경공학회지
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    • 제27권5호
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    • pp.486-490
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    • 2005
  • 본 연구에서는 일반(천연)모래를 대체하여 폐콘크리트 재생잔골재(이하 재생모래)를 하수관거 모래기초용 재료로 활용하였을 경우 재생모래의 지반적 거동(침하)에 대한 다양한 적용성 평가를 실시하였다. 이를 위해 상대적 재료 특성 차이에 따른 침하량 전산모사(FLAC 사용)를 실시하였으며 실내 재하 실험을 통한 즉시침하 평가, 우수에 의해 예상되는 재료특성 변화를 살펴본 후 실규모급 현장 적용성 평가를 실시하였다. 그 결과 FLAC으로 예측된 재생모래기초의 침하량은 $5.0{\times}10^{-6}\;m$ 미만이었으며, 실내 침하실험에서는 침하가 발생되지 않았다. 또한 용출에 인한 재료특성(흡수율 등) 변화 역시 미미하였다. 마지막으로 실규모급 현장 시공의 침하 모니터링 결과, 원지반의 압밀침하로 예상되는 5 mm의 침하만이 발생하였다. 이를 통해서 재생모래의 하수관 모래기초 적용성은 충분한 타당성을 가지는 것으로 판단된다.