• Title/Summary/Keyword: 연약지반 대책공법

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Current Technical Tendency of Chemical Grouting (약액주입공법의 국내ㆍ외 기술 동향)

  • 김진춘
    • Magazine of the Korea Concrete Institute
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    • v.14 no.5
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    • pp.47-53
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    • 2002
  • 근래 지구촌의 산업화가 가속됨에 따라 대지의 활용도가 급속하게 증가하고 있으며 아울러 인구의 증가 및 개개인 삶의 공간적 범주가 점점 확대되면서 지구상에 광범위하게 분포되어 있는 연약지반으로의 관심이 집중되고 있는 실정이다. 최근 국내에서도 고속철도, 인천국제공항, 도심지 지하철 및 서ㆍ남해안 항만공사 등 대규모 국가건설공사가 진행 중에 있으며 더더욱 임해시설의 확충이라든지 인공섬 등의 건설이 활발해지면서 연약지반에 대한 관심이 고조되고 있다. 하지만 연약지반의 특성을 경시한 나머지 터널의 붕락, 주변지반 및 인접건물의 부등침하, 측방유동에 의한 구조물변위 등 대형 안전사고가 빈발하게 발생되어 왔다. 이러한 안전사고의 대책으로서 지반보강을 위한 여러 가지 신공법이 개발되었고, 새로운 터널보조공법이 국내 지하철건설현장에서 널리 쓰여지고 있으며 이러한 공법 등을 통한 성과도 적지 않게 보고되고 있다.(중략)

Cause of Rall Road Slope Failure and Determination of Soil Strength for Remedy (철도사면파괴 원인 및 대책공법 적용을 위한 강도정수 결정)

  • Lee, Seung-Hyun;Kim, Byoung-Il
    • Journal of the Korean Society of Hazard Mitigation
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    • v.4 no.3 s.14
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    • pp.25-31
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    • 2004
  • Rail road slope can be fatted because of existence of unexpected soft subsoil. Purpose of this study is verifying the cause of rail road slope failure and determination of soil strength for remedy. Drilling some boreholes, cone penetration test and field vane test were executed in order to find out the cause of slope failure. In addition, laboratory test was conducted in order to determine soil strength of soft soil sampled as undisturbed state. As a result of both the in-situ and the laboratory tests, the cause of slope failure is thought to be propagation of failure zone by progressive rupture of overconsolidated clay Soft soil strength was determined through back analysis of the failed slope.

The Stability of Bridge Abutment Reinforced by Pile-slab on Soft Ground Undergoing Lateral Flow (측방유동 연약지반상 파일슬래브로 보강된 교대의 안정)

  • Hong, Won-Pyo;Song, Young-Suk
    • Journal of the Korean Geotechnical Society
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    • v.22 no.8
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    • pp.13-24
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    • 2006
  • A site investigation has been performed for bridge abutments constructed on soft ground, which are deformed laterally by backfill. As the result from the evaluation of lateral movement in bridge abutment, the foundation piles were not considered as the passive pile at the design stage and the period for soft ground improvement was not proper. In order to prevent lateral movement of bridge abutment, the pile slab is proposed as a countermeasure. This method can effectively prevent the lateral flow of soft ground, since the overburden surcharge due to backfill on soft ground would be effectively delivered to bedrock through the piles in soft ground. The instrumentation system is designed and installed to investigate the behavior of bridge abutment on soft ground reinforced by pile slab. The instrumentation results show that pile slab effectively resists to the lateral movement of bridge abutment due to backfill. Also, the surcharge loads due to backfill are transmitted to the bedrock through piles. It confirms that the pile slab effectively resists to the lateral movement of bridge abutment due to backfill and the applied design method is reasonable.

A Study on the Lateral Movement of Bridge Abutment Using Centrifuge Test and Numerical Analysis (원심모형시험과 수치해석을 이용한 교대 측방유동에 관한 연구)

  • Yoo, Wan-Kyu;Kim, Ki-Il;Kim, Byoung-Il
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.5
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    • pp.1799-1804
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    • 2010
  • In regard to fill loading structures such as bridge abutments and retaining walls on soft ground, the soft ground undergoes excessive deformation, which causes the lateral movement of the ground, resulting in increased risk of much damage. In this study, a centrifuge model test was conducted to check the possibility of lateral movement of a bridge abutment during back filling in a field, and a numerical analysis considering the lateral movement of the bridge abutment under the influence of the counterweight fill method applied during construction was carried out by using MIDAS/GTS as the FEM(Finite Element Method) program. The results of this study showed that the lateral movement of the abutment can exceed the allowable lateral movement value(15mm), and that the counterweight fill method was effective for the stability of the lateral movement.

A Case Study about Problem EPS Plastic Displacement on High Embankment (고성토 지반의 EPS 소성변형 문제점에 대한 사례연구)

  • Shin, Chang Gun;Seo, Jeong You;Lee, Jong keyn;Chae, Min Lee
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.11
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    • pp.5-12
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    • 2011
  • Numerous studies on the improvement of low strength for soft ground have been performed. EPS, light weight filling material, is used at the study site for stability on consolidation settlement. However, several problems such as settlement of pavement layer and damage of curb occurs. The elevation is lower 1 m than that of designed value by consolidation. It is caused by excessive load during construction. In this study, problems due to overloading on the soft ground where the EPS is used were analyzed and some cases for reasonable improvement method were described. From the results, instructions for design and construction are suggested.

Characteristics for Consolidation and Shear Strength of Bottom Ash Compaction Pile According to Replacement Ratio in Clay (점토지반에 적용된 저회다짐말뚝의 치환율에 따른 압밀침하특성 및 전단특성)

  • Park, Sehyun;Jee, Sunghyun;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.7
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    • pp.57-63
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    • 2010
  • The necessity of effective and economical improvement for soft ground is required more and more as mountains form 70% of country. The soft ground improvement methods for ocean development are sand compaction pile method, displacement method are applied to the soft ground improvement from ocean development pre-loading method, air pressure method, well point method, pack drain method, quicklime pile method etc. Among them, the sand compaction pile method, has many problems such as the economical problem on importing materials due to the lack of sand and destroying the nature while collecting sand. To replace the sand with other alternative materials, a study on the bottom ash compaction pile method because the bottom ash has the similar engineering properties with sand. Therefore, in this study, after compose the complex soil with a replacement rate of 10~80% and a large direct shear test, shear test, consolidation test with replacement rates of bottom ash are performed to estimate whether its shear and consolidation characteristics are suitable for the alternative material of compaction pile method. As a result of test, Shear Strength Parameters tend to be increased in accordance with the increase of replacement ratio of bottom compaction pile, and Settlement Reduction Factor and $t_{90}$ tend to be decreased.