• Title/Summary/Keyword: 지반 개량

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Improvement Effects of Soft Ground from Quick Lime Piles (생석회 말뚝에 의한 연약지반의 개량 효과)

  • Chun, Byung-Sik;Ko, Kab-Soo
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.1
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    • pp.91-101
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    • 2001
  • This paper investigates the effectiveness of quick lime piles for soft ground improvement. The field tests based on the results of the laboratory test were performed, and the results of field tests were compared with those of numerical analyses(FEM). The results of the field test showed that the domestic quick lime was very effective in reducing the water contents of the surrounding ground quickly due to its characteristics such as digestion, absorption, and exothermic reactions. Accordingly, consolidation occurred without any additional load increment and the shear strength of surrounding ground was increased more than twice. Therefore the quick lime pile method could be considered as an excellent improvement technique reducing the improvement period for soft ground. For the practical applications of the quick lime pile method, issues such as hydration heat, particulation and equipment enhancement should be solved through continuous research and development.

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A Study on the Effect of Improvement Boundary of Vertical Drain Method by Finite Element Analysis (유한요소해석을 이용한 연직배수재의 타설범위에 따른 개량효과에 관한 연구)

  • Chang, Y.C.;Kim, J.H.;Lee, J.S.
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.1
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    • pp.5-12
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    • 2004
  • Soft foundation is extensively distributed in coastal areas including our local regions. Embankment load on such soft foundation causes displacement due to lack of base ground supports. Long-term consolidation can result in settlement and destruction of shear failure and structure. Therefore, a variety of vertical drain methods are applied to construction sites to prevent base from breaking and changing for secure construction. This study analyzed the patterns of changes displacement to determine efficient range of improvement since range of vertical drain material determines vertical and horizontal changes based on the width range of under ground improvement. Changes of intensity with distance from embankment edge were also analyzed in the field study of embankment slope.

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Experimental Study on the Reinforcement Effect of Geogrid in Soft Ground Improvement (연약지반 개량시 지오그리드 보강효과에 관한 실험적 연구)

  • Ham, Hyeon-Su;Lee, Sang Duk
    • Journal of the Korean Geosynthetics Society
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    • v.17 no.2
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    • pp.1-7
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    • 2018
  • The number of construction of roads and railroads in soft ground such as coastal areas and wetlands is getting increased. For this reason cases that soft ground improvement is applied are increasing. In general, many ground improvement methods consider only the working conditions at the time or only economy. But if the working condition and economy are taken into consideration together, the number of applicable construction method gets limited. In such a case, a ground improvement method using both the surface layer portion and the deep layer portion is applied. But the basic research on this is still insufficient in practice. Therefore, in this study the reinforcement effect of geogrid was investigated by carrying out the model test realizing the case in which soft surface ground improvement and depth improvement are simultaneously applied. And it was intened to understand the effect of the thickness of surface layer, the diameter and length of the improvement body on the reinforcement effect of geogrid. The result showed that the effect of the surface layer thickness is greater than the effect of the deep layer diameter. Moreover, when the surface layer is reinforced with a geogrid, the strength of the surface layer part is enhanced and this effect of a geogrid reinforcement caused the reduction of surface settlement.

Study on Consolidation Behaviors of Soft Ground by Plastic Board Drain Using Model Tests (실내모형실험에 의한 Plastic Board Drain이 적용된 연약지반의 압밀거동에 관한 연구)

  • You, Seung-Kyong;Hong, Won-Pyo;Yoon, Gil-Lim
    • Journal of the Korean GEO-environmental Society
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    • v.4 no.4
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    • pp.17-23
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    • 2003
  • Accurate prediction of consolidation behaviors of the soft ground improved by plastic board drains is not easy because the consolidation characteristics of the improved ground has not been fully elucidated yet. The shape of drains is one of the most important factors which affect the consolidation characteristics of the improved ground. In this paper, a series of model consolidation tests of soft clay ground improved by plastic board drain were carried out, in order to investigate the effect of both plastic board width and stress level on consolidation characteristics of the improved ground. As the results, behaviors of both settlement and excess pore pressure dissipation were elucidated. Also, the non-uniform distribution of water content in the model ground was obtained. Then, in order to investigate the effect of vertical drainage on the consolidation behavior in the model tests, the comparison between experimental consolidation behaviors and Barron's theoretical ones were carried out. As the results, it was elucidated that the consolidation behavior in the model tests was affected not only by radial drainage but also by vertical drainage.

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The Best Design of the Deep Mixing Method by the rate of substitution (치환율에 따른 심층혼합 처리공법의 최적 설계)

  • Park, Choon-Sik;Lee, Jun-Seok;Jung, Won-Sub
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.123-131
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    • 2009
  • The study decided the improvement depth of soft ground of deep mixing method through 2 and 3 dimension finite element method and following results were acquired. 1. 2 dimension analysis shows settlement 10% more estimated than 3 dimension analysis. 2. When the rate of replacement is under 5%, the settlement sharply increased. 3. The most economical design for the levee was decided 3.0m for width direction, 6.0m for length direction and 8.0m for improvement depth. 4. When the soft ground is developed through deep mixing method, the decision of improvement should be decided through 3 dimension analysis than 2 dimension analysis.

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Development of Decision Making Model for Soft Foundation Improvement Method considering Technically, Economic Effective Factors (기술적 ${\cdot}$ 경제적 영향요소를 고려한 연약지반 개량공법의 의사결정모델 개발)

  • Lee, Heung-Chol;Woo, Sung-Kwon
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2006.11a
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    • pp.698-701
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    • 2006
  • Various improvement methods to treat settlement and stability of structures on soft foundation, that is now continuously introduced after being scrutinized. Therefore, it is very important to select the most suitable method among these various ones. In this study, quantifying the importance of effective factors when making decision, inducing priority and significance weight, systematic standard is proposed for technical, economic factor in making selection of soft foundation improvement method.

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Behavior characteristics of Soft Ground Improved by Granular Pile (Granular Pile에 의해 개량된 연약지반의 거동특성)

  • Chun, Byung-Sik
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.4
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    • pp.63-72
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    • 2001
  • As construction cases on soft ground are increasing, the necessity of ground improvement is also increasing. Granular pile is one of the methods for soft clay and for loose sandy soil. In our country, SCP(Sand Compaction Pile) method using sand material has been mainly used to improve soft ground, but Granular pile with crushed-stone was not used much. However, alternative material such that crushed-stone is needed to substitute for sand due to the environmental and economical problems. In this study, staged load test and consolidation test were performed in the laboratory to observe the behavior of soft ground improved by Granular pile. In order to evaluate the characteristics such as bearing capacity, drainage, and settlement, sand and crushed-stone were applied as each pile material. The test results show that crushed-stone has higher bearing capacity and less settlement than those of sand under similar pore water pressure condition. Therefore, crushed-stone is determined to be appropriate as substitute for sand.

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Characteristics on Electroosmosis Ground Improvement Using Nano-geosynthetics (나노섬유를 이용한 동전기 지반개량에 관한 특성)

  • Ahn, Kwangkuk;Jeong, Kusic;Lee, JunDae
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.4
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    • pp.59-63
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    • 2009
  • In this study, Nano-geosynthetics with electroosmosis method was used and tried to verify the possibility of usage for soft ground improvement. Electroosmosis tests were performed with increasing the voltage level and changing distance between electrodes. The electrokinetic cell was assembled and a Nano-geosynthetics was inserted into the plastic drain board. And electroosmosis was applied to the disturbed kaolin clay. In order to study the effects of ground improvement, ground settlement, water content, collected pore water and shear strength were compared and analyzed with non-applied kaolin clay. Also, the electroosmosis tests were performed with changing the distance between electrodes and the voltage size. As a results of changing the distance and voltage between electrodes, the more voltage size was increased, the more the settlement of ground, shear strength and collected pore water were increased. As the distance between electrodes were increased, the settlement of ground, shear strength, water content and collected pore water were decreased. Finally, Nano-geosynthetics as a material of electrode have the sufficient potential to improve soft ground.

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