• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1271-1278
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• 2010

대규모 절토사면 유지관리 시스템 운영간 적절한 장소에 합리적인 공법을 선정하여 시공하는 것은 중요한 일이다. 다양한 옹벽 시공 공법이 있지만 시공성과 경제성을 감안할 때 옹벽의 기능을 최대한 유지하면서 친환경 기술을 접목할 수 있는 돌망태 옹벽은 최근 사면 보강에 빈번히 시공되고 있다. 장기간 그 기능을 유지해야하는 옹벽의 경우는 유지관리가 더욱더 중요한 과제이다. 따라서 본 연구에서는 돌망태 옹벽의 시공 및 유지관리 점검에 대한 방안을 사례분석을 통하여 제안하고자 한다.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.115-129
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• 2015

The cut-slope of a large-sectional tunnel portal is recognized as a potential area of weakness due to unstable stress distribution and possible permanent displacement. This paper presents a case study of a slope failure and remediation for a large-scale cut-slope at a tunnel portal. Extensive rock-slope brittle failure occurred along discontinuities in the rock mass after 46 mm of rainfall, which caused instability of the upper part of the cut-slope. Based on a geological survey and face mapping, the reason for failure is believed to be the presence of thin clay fill in discontinuities in the weathered rock mass and consequent saturationinduced joint weakening. The granite-gneiss rock mass has a high content of alkali-feldspar, indicating a vulnerability to weathering. Immediately before the slope failure, a sharp increase in displacement rate was indicated by settlement-time histories, and this observation can contribute to the safety management criteria for slope stability. In this case study, emergency remediation was performed to prevent further hazard and to facilitate reconstruction, and counterweight fill and concrete filling of voids were successfully applied. For ultimate remediation, the grid anchor-blocks were used for slope stabilization, and additional rock bolts and grouting were applied inside the tunnel. Limit-equilibrium slope stability analysis and analyses of strereographic projections confirmed the instability of the original slope and the effectiveness of reinforcing methods. After the application of reinforcing measures, instrumental monitoring indicated that the slope and the tunnel remained stable. This case study is expected to serve as a valuable reference for similar engineering cases of large-sectional slope stability.

• Journal of the Korean GEO-environmental Society
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• v.10 no.7
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• pp.151-158
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• 2009

In the early 1990s, soil nailing was first introduced as method of reinforcement for the slope stability and ground excavation, and as its application was increased the improved soil nailing was also developed. Most recently used for grout soil nailing greatly improve the methods and techniques for self-improvement techniques are classified as soil nailing. As the representative for the grout pressure method to improve the join method pressure grouting and improved method for the self-drilled soil nailing, removable soil nailing, upward soil nailing combined with horizontal drainage system. This paper is to compare upward soil nailing combined with horizontal drainage system with downward direction of the soil nailing. In order to study the limit equilibrium slope stability analysis and comparison with factor of safage, excavation for the vertical displacement for comparison with continuous analysis. According to this study, safage factor is decreased considerably using limit equilibrium analysis and makes no odds for the horizontal displacement when soil nail was installed upward.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10b
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• pp.31-42
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• 2001

다양한 방식으로 제작된 유리섬유 강화 플라스틱관(FRP pipe)의 인장 및 휨강도 시험 결과로부터 제작방식에 따른 FRP관의 강도 특성을 비교 검토하였다. 또한, 사면보강대책으로서 FRP 그라우팅 공법의 현장 적용성을 평가하기 위하여, FRP 그라우팅에 따른 지반강도의 증진효과 및 보강재의 인발저항력을 산정하였다. 이를 위하여, 지반의 상대밀도 및 구속압에 따른 보강재 인발저항력의 변화 및 압력주입에 의한 확공효과 평가를 위하여 실내모형실험이 이루어졌다. 또한, FRP 그라우팅이 시공된 현장에서 공내재하시험, 투수시험, 그리고 시추공전단시험 등을 실시하여 FRP 그라우팅에 의한 지반보강 효과 및 차수효과를 정량적으로 산정하였다.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.83-89
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• 2012

Anchor, soil nail and micropile have been widely used for slope reinforcement and foundation. These all methods need grouting work after placing reinforcing member. The pressure injection-grouting techniques helps to increase the bearing capacity of reinforcing member by enhancing larger effective pile diameter and increasing the radial stresses acting on the grout body and causing irregular surface. However, the pressure reinjection-grouting techniques is not commonly used because grouting equipment and practical application example are short and the verification of reinforcing effect is difficult. In this study, the laboratory test was performed to evaluate the reinforcing effect with variation of grouting methods in clay. As a result of the test, the pressure reinjection-grouting techniques showed that the pullout capacity of reinforcing member increased up to 1.22~2.61 times comparing to the gravity fill techniques.

• Journal of the Korean Geosynthetics Society
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• v.8 no.4
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• pp.47-51
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• 2009

The slope failure in the country is caused by mainly rainfall and its type is reported shallow slope failures in general. To investigate the cause of slope failure, the unsaturated soil slope behavior in accordance with rainfall amount studies actively, but there are little studies related the slope erosion and scour by rainfall. The slope erosion and scour by rainfall cause environmental pollution and slope instability, however there are few methods to effectively control them. This research analyzed experimentally how infinite gradients are infiltrated according to the changes of amount of rainfall and the slope of gradients by manufacturing the model of gradient in order to investigate how rainfall infiltrates regarding homogeneous gradients and slope protection method. For this, this experiment measured and analyzed discharge, storage rate occurring in gradients by going on changing amount of rainfall, slope of gradients.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.73-81
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• 2002

Nowadays , the grouted-reinforcing method, which is called FRP(Fiberglass-reinforced-plastic) pipe .reinforcing method, has been introduced in the community of pound reinforcements. The resistance to corrosion and chemical attack high strength to weight ratio, and ease of handling make these pipes a better alternative to steels in tunnel. However, to fully utilize FRP pipes as grouted reinforcing members at the face and the crown in tunnel, their mechanical properties and behaviors and the grout-reinforced underground have to be verified. Laboratory shear tests were conducted to evaluate the mechanical properties for FRP pipes, the grout-reinforced members and the grout-reinforced body of FRP pipes. According to the test results, it was observed that FRP pipes play a dominant role in shearing behavior of the grout-reinforced members and that their shearing resistance exerts after the shearing displacement increases to some extent.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1051-1056
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• 2009

Recently, there are many wide road in korea, so The Large scale cut slopes are increasing. Large scale cut slopes are better then small scale in case of construction and maintenance. General, Reinforced Slopes by Shotcrete are difficult to inspect because of stiff Slope and highly Working Area. So the Inspection Techniques are needed by the Non-contact and Non-destructive. On this Study, We are studying the method about efficient valuation and maintenance of Large scale Reinforced slopes by Shotcrete.

• Journal of the Korean Geotechnical Society
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• v.24 no.12
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• pp.5-12
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• 2008

The reinforced earth wall, which is able to improve the strength of soil highly, is required in case of supporting high surcharge load such as high speed rail way, high embankment road, and massive reinforced earth wall in a mountainous area. And also, it is continuously required that the method is able to minimize the amount of excavated soil on account of environmental issue, boundary of land, etc., on excavation site. However, because the required length of reinforcement should be $60{\sim}80%$ of the height of reinforced earth wall for general reinforced earth wall, in fact the reinforced earth wall is hardly applied on the site of cut slope. In this paper we studied the design and construction cases of hybrid reinforcement retaining wall system combined with steel strips and soil nails, connecting the reinforced earth wall reinforcements to the slope stability reinforcements (soil nails) to ensure sufficient resistance by means of reducing the length of reinforcements of reinforced earth wall. And the feasibility of hybrid reinforcement retaining wall system, suggested by real data measured on site, is also discussed.

• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.37-43
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• 2012

Generally levee or revetment becomes weak by erosion (scour) due to saturation of ground with infiltration, flowing water. So when levee or revetment is constructed, slope reinforcement must be installed to prevent failure. In this study experimental test was performed for verifying shear resistance, horizontal permeability and rooting ability of Geocomb designed to address the shortcomings of 3-dimension Geocell. Geocomb is one of geosynthetics and the advanced system of geogrid. According to the results of shear test, internal friction angle of reinforced ground with Geocomb was increasing compared with existing material and horizontal permeability of ground with Geocomb was bigger than geocell, porous geocell reinforcing ground. Lastly rooting ability of geocomb is most excellent. These results determined for the inner surface of the cell is net structure.