• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.19-25
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• 2000

배수성과 인장강성을 가지는 복합 보강재를 사용하여 보강한 포화점성토의 거동에 선행하중이 미치는 영향을 조사하기위하여 평면변형을 시험을 수행하였다. 보강하지 않은 공시체와 보강한 공시체에 대하여 이방압밀(K=0.3, σ3'=50kPa)을 실시하고 비배수 및 배수전단시험을 일정변형율 속도를 실시하였다. 선행하중을 가한 시험의 경우는 이방압밀후 소정의 선행하중을 가하여 크리이프, 제하, 에이징 후에 비배수 전단시험을 실시하였다. 시험결과 분석한 결과 포화전성성토와 같이 연약한 토질이라도 다짐을 잘하고 보강토의 큰 배수압툭강도를 이용하여 큰 배수압축강도를 이용하여 큰 선행하중을 가하여 과압밀 상태로 함으로써 비배수 전단시에 큰 초기강성을 가지는 것을 알수 있었다. 즉, 점성토의 보강토의 경우 보강에 의한 배수강도의 증가는 큰 선행하중을 가하기 위하여 사용하는 것이 가장 효율적인 것으로 판단된다.

• The Journal of Engineering Geology
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• v.13 no.4
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• pp.491-496
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• 2003

본 기술은 암반사면 보강공법에서 철근보강재인 네일(Nail)에 원추형콘(철근 규격에 따라 기울기 $19~23^{\circ}$, 높이 40~45mm, 아랫변 65~70mm)을 일정한 간격으로 다수 장착하여 그라우트재와 원 지반까지 방사입체형으로 힘을 미치게 하는 암반사면 보강공법이다. 본 신기술 공법은 네일링 공사 시 원추형 콘을 장착, 삽입함으로서 부착력과 인발력을 증가시켜 비탈면 보강공사 시에 안전성을 높인 공법이다. 따라서 네일링공법을 사면붕괴 방지공사에 적극 활용할 수 있으므로 네일링 공법의 사용을 활성화 하며, 지진이나 지반변형 등 외력에 의한 사면붕괴를 사전에 방지할 수 있어 사면재해를 미연에 방지하는 효과가 있다. 또한 현재가지 네일링공법은 인발톤수가 적고 네일에 대한 신빙성 결여로 아주 적은 인발톤수를 필요로 하는 현장이외에는 사용을 기피하는 일이 많았다. 그러나 본 원추형 콘네일 공법은 어스앙카, 록앵커, 보강토공법, 지지말뚝공법, 옹벽 등에 대한 대체공법으로 이용할 수 있는 여건이 충족됨으로 사면보강재로서의 사용 확산이 기대된다.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.1-7
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• 2010

The soil nailing method have been developed on the basis of experimental works as well as theoretical backgrounds. As for the experimental research works, most of the data have been measured during the application of load in service. However, not only the soil-nailed structure behavior in service but also the failure behavior of the structure are the major concerns to evaluate and even establish a design method of soil-nailed walls. In this paper for the apprehension of behavior in the soil-nailed structure which the front of nail is connected, a relatively large-scale experiment was carried out to figure out the failure behavior of soil-nailed wall. A number of data have been acquired and analysis.

• Land and Housing Review
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• v.2 no.2
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• pp.189-194
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• 2011

To reinforce bearing capacity-changed section or different foundation in the same building, empirical or simple tools have been used. To solve this problem, we suggest the analytical solution that can evaluate and reinforce the stability of foundation. To estimate the effect of reinforcement by replacement in different foundation, soil stiffness evaluation method taking into account the influence factor with respect to depth beneath the foundation need to be applied. In this paper, graphs and relevant formulae are suggested to calculate equivalent soil reaction coefficient showing the effect of reinforcement by crushed stone and lean concrete replacement.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.13-22
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• 2021

Pile or column supported embankments have been increasingly employed to construct highway or railway embankments over soft soils. Piles or columns of stiffer material installed in the soft ground can provide the necessary support by transferring the embankment load to a firm stratum using a soil arching. However, there has been reported to occur a relatively large differential settlement between the piles and the untreated soils. Geosynthetic reinforced pile or column supported embankment (GRPS) is often used to minimize the differential settlement. Two dimensional finite element anlyses have been performed on both the column supported embankments and the geogrid reinforced column supported embankments by using a PLAXIS 2D to evaluate the soil arching effect. Based on the results obtained from finite element analyses, the stress reduction ratio decreases as the area replacement ratio increases in the column supported embankments. For the geogrid reinforced column supported embankments, the geogrid reinforcemnt can reduce differential settlements effectively. In additon, the use of stiffer geogrid is appeared to be more effective in reducing the differential settlements.

• Journal of the Korean Geotechnical Society
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• v.29 no.8
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• pp.27-36
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• 2013

LEM (Limit Equilibrium Method) based programs are commonly used for the designs of soil nailing as a slope reinforcement. However, there is a drawback that the interaction between ground and soil nailing is not properly reflected in those programs, which needs to be solved. For economical constructions and designs, research is also required on the support pattern of soil nailing. In this study, therefore, reinforcement effects of soil nailing were compared and analyzed by performing finite difference analyses which could properly consider the interaction between ground and soil nailing. As a result, when the angle from slope to nail is $90^{\circ}$, failure slip surface becomes the largest and thus the factor of safety becomes maximum.

• Geotechnical Engineering
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• v.8 no.3
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• pp.37-50
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• 1992

Liquefaction leads to severe damage to earth structures after an earthquake. In this study, shaking table tests were performed on model waterfront structures as a countermeasure against liquefaction. The waterfront structure was reinforced by a compacted Bone, which was investigated for its effectiveness in protecting the structure from excessive deformation induced by the lateral pressure of liquefied ground. Through the tests . on embankment, double sheet pile wall, and anchor sheet pile wall, good quantitative information on the behavior of flow failure and the extent of reinforcement was obtained. The extent of a compacted zone for the protection of the structure depends on the magnitude of the acceleration during the shaking. The measured deformation was represented in terms of the extent of the compacted zone and the magnitude of the input acceleration.

• Geotechnical Engineering
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• v.9 no.2
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• pp.55-64
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• 1993

When earth structures such as dykes or embankments are constructed on very soft clay foundation, unexpectedly large deformations of earth structures as well as clay foundation are encountered during and after construction. The final constructed section is composed of a portion of embankment above the existing ground level and that which penetrated into the soft foundation soil. This study is aimed to correctly estimate the shape of earth structures which penetrate some depth into the soft clay foundation. In this study the methods to predict penetration depth and deformation shape of embankment section after dumping of construction material. Model tests were carried out to prove the developed theory and FEM analysis. And when the mat is added, reinforcement effect was markedly noticed.

• 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.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.4
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• pp.387-402
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• 2014

In congested urban areas, constructions of tunnel structures have became necessary due to a lack of surface space. The excavation of any tunnel generated the ground disturbances of surrounding ground and displacements is major concern. Therefore, a study of tunnel stability is necessary. In this study, the authors have investigated the stability and failure pattern of tunnel through the model tunnel test. In this study, the close range photogrammetry was used to measure the ground deformation. The measured data was converted to displacement vectors and contours. And then it compared to FE analysis and empirical formula. In addition, this study presented the comparison between steel pipe reinforced model tunnel and unreinforced model tunnel. The ground deformation for both the steel pipe reinforced model tunnel and the unreinforced model tunnel was analysed.