• Title/Summary/Keyword: 토의

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Prediction of Physical Characteristics of Cement-Admixed Clay Ground (점토-시멘트 혼합 지반의 물리적 특성 예측)

  • Park, Minchul;Jeon, Jesung;Jeong, Sangguk;Lee, Song
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.2
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    • pp.529-536
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    • 2014
  • Physical characteristics of cement-admixed clay such as water content, specific gravity, unit weight and void ratio are main factors for strength, compressibility and prediction of consolidation behavior. In the past, the physical characteristics of admixed soils could be understanded through complex laboratory tests and field survey after construction. In this study, the tests were performed with conditions such as clay water contents 0%-170%, cement contents 5%-25% and curing period 3-90days after that analyzed for changes which are water content, specific gravity unit weight and void ratio of admixed soils. A prediction of properties through mechanical relationships with clay in situ water content, cement content and curing period could be proposed using the test results. The prediction equation of void ratio of admixed soils was derived using void ratio equation in geotechnical engineering and compared with test results of bangkok clay and then this study could be verified.

A Numerical Study on Granular Compaction Pile Method Reinforcing by Using Lean-Mixed Concrete (빈배합 콘크리트로 보강된 조립토 다짐말뚝공법에 관한 기초연구)

  • Kim, Seung-Wook;Kim, Hong-Taek;Kim, Jeong-Ho;Baek, Seung-Cheol
    • Journal of the Korean GEO-environmental Society
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    • v.7 no.1
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    • pp.5-18
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    • 2006
  • Stone column or granular compaction pile have been used in widely during the several decades as a technique to reinforce soft cohesive soils and increase bearing capacity, accelerate consolidation settlement of the foundation soil. The bearing capacity of the granular compaction pile is governed mainly by the lateral confining pressure mobilized in the native soft soil to restrain bulging collapse of the granular pile. Therefore, the technique becomes unfeasible in soft, compressible clayey soils that do not provide sufficient lateral confinement. This paper presents the main results of numerical study of granular compaction pile which is partly mixed with lean concrete. 3D finite element analyses are performed with composite reinforced foundations by both granular compaction pile and partly mixed granular compaction pile with lean-mixed concrete. Finally, a regression formula for calculating settlement reduction coefficients is proposed in this study by using numerical analysis results and applicability of the proposed method is identified by a series of parametric study about settlement reduction coefficients.

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Strength and Deformation Characteristics, and Numerial Analysis for Cement Admixed Clay and Composite Ground (시멘트 혼합토 및 복합지반의 강도, 변형 특성 및 수치해석)

  • Jeon, Jesung
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.8
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    • pp.51-58
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    • 2014
  • In this research, the composite grounds including original clay and soil-cement were constructed for conducting uniaxial compression test. Strength and deformation properties were analysed using results of laboratory tests with variations of water content of clay, replacement ratio and cement content. Numerical simulation using 3D distinct element method was conducted for soil cement. For strength of composite ground that contains more than cement contents of 15 %, it is more effective to increase cement content than increase of replacement ratio. Strength and elastic modulus of composite ground could be predicted by regression equations using uniaxial compression strength of clay, cement content of soil cement and replacement ratio. For strength and elastic modulus of soil cement, which is most important things for predicting final strength and elastic modulus of composite ground, numerical simulation using the distinct element method adapted bonding model could be used to verify laboratory test, and predict strength and elastic modulus.

Flow and Compressive Strength Properties of Low-Cement Soil Concrete (저시멘트 소일콘크리트의 유동성 및 압축강도 특성)

  • Park, Jong-Beom;Yang, Keun-Hyeok;Hwang, Chul-Sung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.1
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    • pp.1-7
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    • 2018
  • This study examined the effect of binder-to-soil ratio(B/S) and water-to-binder ratio(W/B) on the flow and compressive strength development of soil concrete using high-volume supplementary cementitious materials. As a partial replacement of ordinary portland cement, 10% by-pass dust, 40% ground granulated blast-furnace slag, and 25% circulating fluidized bed combustion fly ash were determined in the preliminary tests. Using the low-cement binder incorporated with clay soil or sandy soil, a total of 18 soil concrete mixtures was prepared. The flow of the soil concrete tended to increase with the increase in W/B and B/S, regardless of the type of soils. The compressive strength was commonly higher in sandy soil concrete than in clay soil concrete with the same mixture condition. Considering the high-workability and compressive strength development, it could be recommended for low-cement soil concrete to be mixed under the following condition: B/S of 0.35 and W/B of 175%.