• Title, Summary, Keyword: Ground Improvement

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Effects of Ground Improvement Depending on the Type of Soil by Compaction Grouting System (토질의 종류에 따른 CGS공법의 지반개량효과에 관한 연구)

  • Chun, Byung-Sik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.3
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    • pp.211-220
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    • 2002
  • CGS(Compaction Grouting System) is widely used in reinforcement of structural foundation and ground improvement in soft ground. But the effects of ground improvement depending on the type of soil must be studied in order to adopt in various soils (granular soil and cohesive soil). In this study, characteristics of ground improvement (the increase of N value, increase in unit weight, vertical displacement on the ground surface) by CGS method was compared through two cases that were performed in granular and cohesive soil. The results show that the closer to the grout hole, the more increase in N value and this trend appear distinctly in granular soil. Unit weight of ground increase largely near by the grout hole and decrease in far from it independently of the soil type. The vertical displacement on the ground surface appeared in smaller area in case of granular soil than cohesive soil.

Characteristics of Ground Improvement by Compaction Grouting System in Filled Ground (매립토층에서 CGS에 의한 지반개량특성에 관한 연구)

  • 천병식;여유현;정영교;정완균;정의원;김우종
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.425-432
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    • 2001
  • Compaction Grouting System, the method which makes ground compact by injection of low slump mortar, Is widely used for reinforcement of soft ground, restoration of structures happened differential settlement, underpinning and restoration of damaged dam core. The quantitive analysis of ground improvement for this method has not performed yet. So, design parameters about thls method must be studied through performance of CGS in various types of soil to make CGS adaptable widely. In this study PBT, SPT and field density test were performed for analysis of the characteristics of ground improvement and pressuremeter and inclinometer were installed for analysis of the characteristics of compaction in adjacent ground. In this paper, denoted much effects for filled ground that increasing of the bearing capacity, confirming the displacement of adjacent ground and the effective radius of injection.

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A study on the variety of strength about soft ground improvement material according to Mixed soil (혼합대상 토질에 따른 지반개량재의 강도 변화에 관한 연구)

  • Lee, Kwang-Joon
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1023-1030
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    • 2005
  • This study is an experiment paper about the ground improvement material which using the waste residual(slag and paper fly ash) by fire. we are research to concern according to the soil to mix the ground improvement material at show strength effectiveness. Also, we can expect a long time strength increase effectiveness as reduce the dryness contraction. They are distinguished to the clay of the reclamation ground and silty sand soil. We examined around an uniaxial compress test and scanning electron microscopy. The uniaxial stress increases according to the increase of the mixed ratio of ground improvement material and the water contents have been reduced the strength value. A clay's improvement effectiveness is big but in the silty sand soil to express small effectiveness. A ground improvement material mixing of the quantity to write can not expect the effect of Ettringite.

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Effects of Deep Mixed Method Construction Within the Soft ground (연약지반의 심층혼합처리공법의 시공효과)

  • ;;Li Guang Fan
    • Journal of the Korea Institute of Building Construction
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    • v.1 no.1
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    • pp.160-168
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    • 2001
  • This study aims at the development of computer program for the deformation analysis of soft ground, and using this computer program, study the constraint effect of deformation heaving, lateral displacement of the soft ground reinforced with improvement of soft ground up to hard strata, under intact state(natural). The following results are obtained. 1. Improvement of soft ground to the hard strata works well against the settlement of neighboring ground. 2. the larger the rigidity or width of improvement of layer to hard strata is, the less settlement occurs. 3. Improvement of soft ground to the hard strata is of no use.

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An Analytical Study on the Determination of the Lowest Improvement Depth of Deep Mixing Method (심층혼합공법의 최저 개량 심도 결정에 관한 해석적 연구)

  • Park, Choon-Sik;Song, Ji-Won
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.1
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    • pp.35-44
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    • 2020
  • Design techniques for the deep mixing method, one of the soft ground improvement methods, include two ways to interpret the ground as composite ground and pile ground. However, since comparative studies on these two approaches are insufficient, it is difficult to clearly define the analysis criteria in the design. In this study, two-dimensional and three-dimensional analyses have been performed with different conditions. The three conditions, the embankment height, depth of soft ground, and replacement ratio of reinforcement zones were varied and the analysis was performed on the basis of the assumption of composite ground and pile ground for each condition. As a result, the minimum depth of improvement in the two-dimensional analysis was deeper by 6.85~9.08% than in the three-dimensional analysis. The pile ground analysis showed that the depth of improvement was deeper by 12.22~14.45% than the composite ground analysis. Based on these results, it is concluded that for more accurate design, three-dimensional analysis should be performed rather than two-dimensional analysis. also, it is judged that necessary to analyze the ground as composite ground for economical design, and as the pile ground analysis for stable design.

RELEVANCE OF BAND DRAIN QUALITY TO EFFECTIVENESS OF GROUND IMPROVEMENT (밴드 드레인의 품질과 연약지반개량효과와의 관련)

  • 김상규
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1.3-20
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    • 1995
  • The use of band drains for ground improvement has been increased throughout the world during the past 15 years. Apart from other ground improvement techniques, the quality of band drains affects greatly the well resistance of drains, discharge capacity and clogginf tests for four drains selected are carried out and quality is examined.

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Analysis of Ground Improvement Effect of Low Vibration Sand Compaction Pile Method (저진동 모래다짐말뚝(LVSCP)의 지반개량효과 분석)

  • Kim, Jong-Kook;Cha, Jun-Tae;Lee, Jae-Chang;Chae, Young-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1234-1242
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    • 2010
  • In this study, the effect of noise and vibration, and influence of ground improvement are evaluated and its application is analyzed through the example of SCP designed at ground improvement in Song-Do international city. consequently, it showes even comfortable result that it is about 5.0m of inner space, when the LVSCP method is applied, rather than that it is about 30m of inner space when the existing SCP is applied in vibration control standards 2.0mm/sec. In the noise, now that the many differences according to environmental factors like other equipment noise, limited space and so on at the time of the construction by LVSCP method are coming out, so we think that appro itate measures are needed according to surroundings. By the way, when it comes to the estimation of the ground improvement work before and after an improvement of LVSCP method, its result shows that it is satisfacttion to all the standards of compaction control in dregded and reclaimed ground and sedimentary clay layer.

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Stress Monitoring System for Buried Gas Pipeline in Poor Ground (연약지반 배관응력 모니터링 시스템 개발 및 적용)

  • Hong, Seong-Kyeong;Kim, Joon-Ho;Jeong, Sek-Young
    • Journal of the Korean Society of Safety
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    • v.21 no.1
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    • pp.41-47
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    • 2006
  • This paper introduces stress monitoring system for buried gas pipeline in poor ground. During the six months of improvement construction of poor ground, maximum settlement of gas pipeline is about 40 cm. This value represents relative small compared to the initial settlement estimation of ground improvement construction plan, 90 cm. Also, this paper includes the result of finite element analysis of gas pipeline to confirm safety of pipelines in poor ground. The stress monitoring system for gas pipeline was developed to guarantee the safety of buried gas pipeline in poor ground. Eventually, the ground improvement workings are ended safely and it is proved that the pipeline has no safety problem.

Case Study for Improvement of Marine Clay and Dredgedfill Ground by CGS Method (CGS공법에 의한 해성점토 및 준설매립지반의 기초보강 사례)

  • Shin, Eun-Chul;Chung, Duek-Kyo;Seo, Kui-Chang;Lee, Myung-Shin
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.480-488
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    • 2010
  • The CGS method is non-discharge replacement method improving ground stiffness by the effect of static compaction with injecting very low slump mortar into ground, and is applied for increasing bearing capacity and filling ground cavity by lifting or restoring differential settled structures and preventing differential settlement. This paper suggests design of ground improvement and construction case history for civil engineering structures by CGS method. This method can be used for reinforcing soft ground and liquefaction of loose sandy soil. This method was used in SongDo area in Incheon Economic Free Zone due to its low vibration of ground while it can improve the soft soil where underground structures(subway and box culvert) are already existed.

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The Reality and Problem of Soft Ground Improvement Construction (연약지반 개량 시공의 실제와 문제점)

  • Choi, Gwi-Bong;Hwang, Soung-Won;Kim, Jong-Ryeol
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.672-679
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    • 2008
  • During recent years, the large soft ground improvements very rapidly increase with industrial development and it is the types and scales of structure that is enlarged by degree. Then, we must enter construct equipment to improve soft ground and we fulfilled works by carrying out soft clay soil to gain trafficability for them. For improving the soft ground, we lay geotextile on soft clay ground and fill the filter sand that can drain the pore water. Then, we landfill cover soil for come by trafficability of construction tools. Ater that we penetrate vertical drain for dehydration through soft ground. there are very complicated works. For these reason we suggest the methods of soft ground improvement constructions.

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