• Title/Summary/Keyword: Consolidation Settlement

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Relationship Between Compression Index and Swelling Index for Remolded Clays (교란점토의 압축지수 및 팽창지수의 관계에 대해서)

  • Park, Jong-Hwa;Tatsuya, Koumoto
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.317-320
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    • 2002
  • The compression index, $C'_c$ and the swelling index, $C'_s$ which are obtained from the e-log p curve of the consolidation test, are used to calculate the consolidation settlement. In this research, $C'_c$ and the two new methods of $C'_s$ i.e. $C'_{s1}$, $C'_{sm}$ for remolded clays were examined with the $({\omega}_0-{\omega}_p)$ and $(e_0-e_p)$ which are satisfied with the condition and the type of soil. Moreover, the relationships of $C'_{s1}$, and $C'_{sm}$ versus $C'_c$ were obtained.

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The Study on permeability enhancement in smear zone using electro-osmotic pressure (전기 삼투압을 이용한 교란영역의 투수성 개선에 관한 연구)

  • Ahn, Byung-Wook;Noh, Hee-Jeon;Kim, Hyun-Ki;Cho, Nam-Jun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.435-441
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    • 2008
  • More time is required for consolidating soft clay when its hydraulic conductivity around the vertical drains is reduced by soil disturbance. One of the methods to be proposed to solve such problem is the electro-osmotic flow application. This study presents the experimental results of model tests using a modified oedometer and a large-scale cylinder with a sand drain. Results show that the development of negative excessive pore water pressure due to the DC electrical field in saturated clay can be transformed to additional loads causing more consolidation settlement.

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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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The Effects of Negative Pressure on Horizontal Drain Method (수명배수공법에 있어서 부압의 영향에 관한 실험적 연구)

  • 김정기;김지용;정승용;김수삼
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.551-558
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    • 2001
  • The horizontal drain method is one of methods improving reclamation ground. This method reduces consolidation time by using drained installed horizontally, and negative pressure is applied on end of these drains by vacuum pump. But, effective negative pressure still wasn't evaluated in applying this method to reclamation ground. To estimate optimum negative pressure, soil box test that make a model the in-situ by installing horizontal drains in the center is performed pressing different vacuum pressure In the laboratory, and the variations in settlement and volume of drained water through the drains during consolidation process were measured. Also, water content with distance from drain and with depth is measured after the test.

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The Behavior of Undrained Pore Water Pressure in Normally Consolidated and Saturated Clay(II) - Visco Elastic Analysis Model - (포화된 정규압밀 점성토에서 비배수 공극수압의 거동(II) - 점탄성 해석 모델 -)

  • 임성훈
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.4
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    • pp.137-143
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    • 2003
  • The initial condition of $\Delta \sigma_3 \;=\; \Delta u$ is used for analyzing the time dependent behavior of ground. This is based on the concept that the coefficient of pore water B is the unity on the condition of saturation. but some measured consolidation data in the field showed that the pore water pressure was not dissipated as time elapsed but it was maintained constant value or it's dissipation rate was slower than that of the predicted. and so the measured data of pore water pressure was not consistent with that of settlement. In this study, the rheological model for the pore water pressure behavior on undrained condition was induced and compared with the experiment data of the literature. The result showed that the suggested model was consistent well with the result of experiment, but the suggested model could not explain the effect of the decrease of void ratio according to consolidation.

Physical and Mechanical Properties of Waterwaste Sludge and Stabilized Sludge (슬러지 및 안정화시킨 하수 슬러지의 물리적.역학적 특성)

  • 송창섭
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.41 no.6
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    • pp.97-104
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    • 1999
  • An experimental investigation was carried out to study the feasibility of using the stabiliozed sludge, as a backfill and cutoff-water materials for embankment structures. For stabilizing of sludge, hydrated lime and quick lime were used as additive, and a series of tests were performed on the sludge and the stabilized sludge to examine their physical and mechanical properties , compaction, compressive strength, hydraulic conuctivity and consolidation characteristics. From the test results, physical and mechanical properties of the stabilized sludge were improved as compared with the sludge. Especially from the viewpoint of physcial property, consolidation or settlement and cutoff-water, quick lime is more effective than the hydrated lime as a stabilization addtive. But, viewpoint of compaction and shear strength, hydrated lime is more effective than the quick lime as a atabilization additive. As a result of this study, it was found that the stabilized sludge can be developed the backfill and cutoff-water materials, improved the stabilizing method of sludge.

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Analyses on Consolidation Characteristics of Dredged and Reclaimed Soils in Busan Area (부산지역 준설매립지반의 압밀거동 특성 분석)

  • Yoo, Nam-Jae;Kim, Dong-Gun;Hwang, Hee-Seok
    • Journal of Industrial Technology
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    • v.32 no.A
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    • pp.87-94
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    • 2012
  • For soils with high void ratios, the inverse method of utilizing results obtained from centrifuge model test was used to find the constitutive relation of effective stress - void ratio - permeability whereas conventional oedometer test and constant rate of strain consolidation(CRS) test about settlement of interface and pore pressure and distribution with time were compared with numerically estimated values to confirm such a constitutive relation as obtained from the inverse method. As results of numerical method, the volumetric ratio and reclamation velocity were obtained for the reclamation condition.

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A Study on Caissons for Accelerating Consolidation (압밀촉진 케이슨 기초공법에 관한 연구)

  • 박정순;조남준
    • Journal of the Korean Geotechnical Society
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    • v.17 no.2
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    • pp.95-101
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    • 2001
  • 연약한 점토 지반에 안벽을 축조하고 매립하는 경우, 안벽의 기초로서 케이슨 기초공법이 종종 쓰이고 있다. 케이슨 기초는 안벽의 연직 하중을 지지층에 전달할 뿐만 아니라, 매립하중에 의한 연약 점토의 횡방향 소성 유동에 대하여는 매우 효과적인 공법으로 호안공사에서 그 사용 빈도가 증가하고 있는 추세이다. 반면 매립하중에 의해 점토지반에서 장기간에 걸쳐 발생하는 압밀침하에 대해서는 아무런 역할을 하지 못하는 단점이 있다. 따라서 본 연구에서는 기존 케이슨 기초의 배면에 다수의 강관 배수공을 설치함으로써 과잉간극수압의 횡방향 소산을 촉진시켜 압밀 시간을 단축시키는 \"매립측 연약점토 압밀촉진 케이슨 기초공법\"을 제안하였다. 이 새로운 케이슨 공법의 압밀촉진 효과를 분석하기 위하여 2차원 압밀방정식의 해석해를 유도하였다. 연구결과, 등방성 점토에서 압밀촉진 케이슨 사용시 ξ=0.1인 단면에서 평균압밀도 50%, 90%에 이르는 시간이 기존 케이슨을 사용한 것에 비해 각각 약 7배, 3.5배 단축되는 것으로 나타났다. 것으로 나타났다.

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Nonlinear Compression Characteristics of Highly Plastic Clays and Silts (고소성점토 및 실트의 비선형 압밀특성)

  • Han, Dae-Hee;Im, Jong-Chul;Kwon, Jung-Keun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1081-1089
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    • 2008
  • Highly plastic clays in their normally consolidated state are not linear but are concave upwards. Thus their compression index deceases with the increase in consolidation pressure. Likeness the e - log ${\sigma}\;_{\upsilon}\;'$ curves of the silts are not linear but are convex upwards. In this paper, conducted consolidation test with four undisturbed field soil and found that their e - log ${\sigma}\;_{\upsilon}\;'$ plots are not linear. And analyzed difference of settlement between computed value with compression index($C_c$) and computed value with improved compression index($\mathbb{C}$).

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Lateral Displacement and Ground Rising Movement with Soil Embankment (성토에 따른 지반의 측방변위와 지표면 융기량)

  • Jeong, Ji-Cheol;Shin, Bang-Woong;Oh, Se-Wook
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.2
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    • pp.63-69
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    • 2004
  • During and after the construction of embankment on soft ground, consolidation settlements and lateral displacements develop. But generally it's very difficult to predict the magnitude of lateral deformations and the correct distribution of lateral displacements with depth under the toe of embankment because the consolidation and the shear deformations of soft ground occur simultaneously. This study shows that later displacements of ground surface arise by embankment loading act on soft clay hight water contents in laboratory model testing. The results of model test are observed settlement of embankment, amount of maximum rising and displacement of ground surface with loading velocity. The formula were proposed to predict lateral movement by test series.

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