• Title/Summary/Keyword: 기초침하

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Study on Effects of Foundation Behavior influencing Pavement deteriorated by Chloride ion (염해를 받는 해안도로의 포장체에 미치는 하부지반의 영향에 관한 연구)

  • Cho, Gye-Chun;Jo, Seon-Ah
    • Proceedings of the KAIS Fall Conference
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    • 2009.12a
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    • pp.367-369
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    • 2009
  • 해안도로에 건설되는 콘크리트 포장체는 염해의 영향을 받는다. 또한 해안도로의 기초가 되는 지반은 약 5%가 연약지반으로 이루어져 있으며, 이에 대해 적절한 처리가 이루어지지 않으면 시간이 지남에 따라 침하가 발생하여 포장체에 부정적인 영향을 끼칠 수 있다. 연약지반의 장기적 거동에 의한 부등침하로 콘크리트 포장체에 균열이 발생할 경우, 염분의 침투 및 포장체내로의 확산이 가속되어 균열을 더욱 심화시키는 역할을 하게 된다. 본 연구에서는 이와 같이 포장체와 하부지반의 상호 유기적인 관계를 규명하고 부정적 영향의 정도를 예측함으로써 해안도로의 건전성 및 공용성을 확보를 위한 근간을 제공하고자 한다.

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A Model test on the behavior of Backfill Materials improvement at Abutment (교대 뒤채움 재질 변경시 지반거동에 관한 실내모형실험)

  • Jeon, Nam-Soo;Shin, Jae-Hong;Cho, Min-Hyuk;Choe, Myong-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1061-1064
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    • 2010
  • 뒷채움재료의 선정기준으로 구조물과 연이은 토공부 사이의 부등침하를 최소화하기 위해 맞물림(Interlocking)효과 및 다짐성이 우수하고 배수가 원활히 될 수 있는 입상재료인 선택층 재료를 사용하는 것으로 규정 및 설계하고 있다. 일률적으로 정해진 현재의 뒤채움재료 선정기준은 건설초기에 손쉽게 구할 수 있었던 선택층 재료인 SB-1의 공급이 어려워져 적절하게 현장여건을 고려하기 곤란하다. 공학적 측면에서 지나치게 안전측으로 선택 및 설계되는 경우가 있어 공사비의 상승 등 시공성과 경제성 측면에서 많은 문제점을 가지고 있다. 본 연구에서는 실내 모형토조를 이용하여 뒤채움 완료 후 뒤채움부 상단에서 교통하중에 의한 장기동적토압을 모사해 뒤채움부의 장기 침하량과 수직, 수평토압을 측정 비교해 교대 뒤채움부 재질 변경을 위한 기초자료로 활용하고자 한다.

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A Study on the Numerical Model for Predicting Depth of Replacement and Consolidation by Embankment on Weak Soil (항만구조물의 기초처리공법 중 수치 PROGRAM을 이용한 강제치환 예상 추정선에 관한 연구)

  • 이상화;이영재
    • Journal of Ocean Engineering and Technology
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    • v.14 no.3
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    • pp.61-65
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    • 2000
  • The estimation of soil stabilization is of great importance concerning the construction of structures on weak soil. A typical model of soil stabilization is considered as replacement, which is based on ground at failure due to direct loading on weak soil. The calculation of the line of predicting settlement was carried out using RPL and DIKE programs. The DIKE program is showing a tendency to excel totally about this embankment of the seadike. Hereafter, This program will be contributed widely to the construction of offshore structures on weak soil.

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부산 신항 조성지역의 지반 개량된 미고결 퇴적층에 대한 물리탐사

  • 김성욱;김인수;김동곤;고윤경;조기영
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.442-446
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    • 2003
  • 연약지반으로 분류되는 조간대 퇴적층의 연구는 제한적인 시추자료에 의존하고 있다. 비파괴 지반조사 방법은 시추자료에서 획득할 수 없는 지층의 측방변화와 지질 이상대를 확인할 수 있는 대안이 될 수 있다. 지구물리탐사 방법은 현장 토질조사와 같이 직접적인 지반조사 방법과 병행할 경우 지반을 이해하는데 있어 한층 나은 결과를 얻을 수 있다. 부산신항 배후부지 조성지역에서 매질의 상이한 특성에 기초한 비파괴 지반조사 방법으로 이용되는 지구물리탐사를 실시하였다. 각 탐사의 결과는 서로 유사한 지층경계를 나타내며, 시추와 매립공사의 결과와도 일치한다. 또한 계측을 위해 매설된 침하판이나 매설관로의 탐지, 압밀차이에 의한 부등 침하의 측방변화 등과 같이 시추조사에서 인지하기 어려운 부분에 대한 정보를 제공하고 있다.

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Analysis of Settlement Characteristics of Shallow Foundation on Sandy Soil Overlained by Rigid Ground (강성지반위 사질토층에 위치한 얕은기초의 침하량특성분석)

  • Hwang, Hui-Seok;Kim, Dong-Geon;Yoo, Nam-Jae
    • Journal of Industrial Technology
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    • v.34
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    • pp.45-52
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    • 2014
  • In this paper the settlement characteristic of shallow foundation on sandy soil overlained by rigid ground was investigated by analyzing results of model tests. For model experiments, model tests were performed with sandy soils sampled from the field, changing the relative density of sandy soil and the ratio of thickness of sandy layer(H) to the width of model strip footing(B). As result of tests, settlement of sandy soils increases as the value of H/B increases, whereas it increases with relative density of soil. Bearing capacity decreases as the thickness of the sand layer relative to the footing width increases. In order to analyze the settlement characteristics of sandy ground, the results of model tests were compared with the predicted values using the empirical formulas proposed by Terzaghi, De Beer and Schmertmann. The method by De Beer was found to be in good agreements with test results.

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The study on the bearing capacity and settlement of a foundation placed over a tunnel (Tunnel 상부지반의 기초 지지력과 침하에 관한 연구)

  • 김수삼;정승용;김용수;권태창
    • Journal of the Korean Society for Railway
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    • v.2 no.4
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    • pp.20-31
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    • 1999
  • When a foundation on the ground with tunnel is constructed, the ultimate bearing capacity of a footing is reduced by tunnel. In practice, structure may bate a considerable damage because of large settlement. This study shows that the settlement which is caused by variety of the ultimated bearing capacity leads fatal damages to the footing above tunnel. Therefore, it is necessary to study on the reduction both of the ultimate bearing capacity which leads a failure and of tolerable settlement which satisfies the safety of the building. For this reason, the variety of ultimated bearing capacity was analyzed using tub-dimensional elasto-plastic finite difference method in this paper. As a result, bearing capacity of the foundation above tunnel should be determined after establishing limit of allowable settlement and considering reduction-ratio of bearing capacity.

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Analysis of seabed behavior in foundation structure under wave loading (파랑 작용하에 있는 기초 구조물 해저지반의 거동에 관한 연구)

  • Yun, Seong-Kyu;Lee, Min-Ah;Choi, Seong-Jun;Kim, Tae-Hyung
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.187-190
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    • 2011
  • 방파제 설계시 고려되는 파랑하중에 대한 설계 방법으로 기존 설계는 정수압만을 고려한 정적해석을 실시하였으며 최근 설계에서는 정정해석과 동적해석을 동시에 실시하고 있다. 하지만 이때의 동적해석 방법은 파랑하중에 의한 파압을 구조물내의 임의의 지점에서만 산정하여 등가파압으로 적용하여 해석을 하고 있다. 본 연구에서는 방파제의 경사면뿐만 아니라 해저지반에서의 파압을 추가적으로 고려함과 동시에 등 가파압이 아닌 모든 절점에서의 파압을 산정하여 파압을 적용하였다. 그 결과 현재의 설계법과 본연구의 설계법으로 구한 침하량의 값이 상당한 차이를 나타내고 있다.

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A Study on Behavior of Elastic Settlement of Coastal Structure on Sandy Ground (모래층 지반 안벽구조물의 탄성침하거동 연구)

  • Yoo, Nam-Jae;Jun, Sang-Hyun;Jeon, Jin-Yong
    • Journal of Industrial Technology
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    • v.27 no.B
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    • pp.201-208
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    • 2007
  • This paper is research results of investigating the elastic settlement behavior of the coastal caisson structure built on the sandy deposit by comparing results of centrifuge model experiments and those of existing methods of estimating elastic settlement. Basic soil property tests such as specific gravity test, grain size distribution test and organic content test with disturbed soil sampled from the site were carried out. The centrifuge experiment of model satisfying the required design criteria was performed under 50 of artificial accelerated gravitational force condition. The Centrifuge model experimental results were compared and analyzed with the current methods of estimating settlement based on the elastic modulus obtained from the results of odeometer tests and empirical methods from literature reviews.

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Analysis of the Behavior Characteristics of Pile Foundations Responding to Ground Deformation (지반 변형 대응형 말뚝 기초의 거동 특성 분석)

  • Lee, Junwon;Shin, Sehee;Lee, Haklin;Kim, Dongwook;Lee, Kicheol
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.4
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    • pp.21-32
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    • 2020
  • As the global large-scale infrastructure construction market expands, the construction of civil engineering structures in extreme environments such as cold or hot regions is being planned or constructed. Accordingly, the construction of the pile foundation is essential to secure the bearing capacity of the upper structure, but there is a concern about loss of stability and function of the pile foundation due to the possibility of ground deformation in extreme cold and hot regions. Therefore, in this study, a new type of pile foundation is developed to respond with the deformation of the ground, and the ground deformation that can occur in extreme cold and hot region is largely divided into heaving and settlement. The new type of pile foundation is a form in which a cylinder capable of shrinkage and expansion is inserted inside the steel pipe pile, and the effect of the cylinder during the heaving and settlement process was analyzed numerically. As a result of the numerical analysis, the ground heaving caused excessive tensile stress of the pile, and the expansion condition of the cylinder shared the tensile stress acting on the pile and reduced the axial stress acting on the pile. Ground settlement increased the compressive stress of the pile due to the occurrence of negative skin friction. The cylinder must be positioned below the neutral point and behave in shrinkage for optimum efficiency. However, the amount and location of shrinkage and expansion of cylinder must comply with the allowable displacement range of the upper structure. It is judged that the design needs to be considered.

Engineering Characteristic of High Density Expansion Materials for Structure Restoration Technology (기초침하복원을 위한 급속 팽창재료의 공학적 특성에 관한 연구)

  • Shin, Eun-Chul;Cha, Yong-In
    • Journal of the Korean Geosynthetics Society
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    • v.7 no.2
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    • pp.1-5
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    • 2008
  • The differential settlement on ordinary concrete buildings and paved roads are often occurred and which caused the failure of structure. The grouting method can be used for correcting the settlement of the structure. However, the grouting method has a disadvantage like that it takes a long time period to get a desired strength, and it is not a continuous in the phase of reinforced effect. In this paper, as an injecting material called GPCON to complement disadvantage, it is estimated about the characteristic that has a high-density expansion. With the changing of ground conditions and amount of injection, the change of physical strength on compression, the stability against chemical material are studied through the filming of SEM. The physical strength with compression is developed to high strength due to mixing with other material. It is not react with most of the material on chemical conditions except the component of alcohol. Through the SEM test. it is confirmed that the strength of material was increased as formation is being densified.

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