• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.97-108
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• 2010

발포우레탄 패커를 이용한 압력식 쏘일네일링 공법은 기존 쏘일네일링 공법의 단점을 보완하기 위하여 개발되었으며, 그라우팅 두부에 패커를 설치하여 네일 정착부를 완전히 밀폐하고 압력 그라우팅을 실시하여 정착부의 유효직경 및 인발저항력을 증가시켜 안전율을 향상시키는 공법이다. 압력식 쏘일네일링 공법에 대한 효용성을 검증하기 위하여 발포우레탄 패커 특성시험 및 현장조건을 묘사한 실내 그라우팅 주입실험, 현장시험 및 FEM해석을 수행하였다. 본 공법의 필수요소인 발포우레탄 패커의 정착력 확인을 위한 패커 특성시험 결과, 공내에 작용하는 압력에 대하여 패커가 충분히 저항함을 알 수 있었으며, 인발저항력 증가 원인 분석을 위한 실내 및 현장 시험결과, 압력 그라우트에 의하여 그라우트의 품질확보, 보강력증가 및 주변지반의 압밀효과를 확인 하였다. 끝으로 압력식 쏘일네일링 공법을 적용한 사면 및 흙막이 벽체 설계/시공 사례를 분석하여 현장 적용시 본 공법의 효용성 및 대처능력의 우수함을 입증하였다.

• 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.

• Journal of the Korean Geotechnical Society
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• v.16 no.3
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• pp.107-117
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• 2000

쏘일네일 벽체는 국낸에서 과거 10년간 가시설 및 영구구조물에 상당수 시공되어 왔다. 그러나 쏘일네일링 공법은 많은 장점이 있음에도 불구하고 인접한 건물의 하부에 쏘일네일이 삽입되는 것을 허용하지 않아 제한적으로 사용되고 있는 실정이다. 따라서 본 논문에서는 쏘일네일이 인접한 건물의 하부에 삽입되는 문제를 해결하고 철근을 재활용할 수 있는 방안으로 제거식 쏘일네일링 공법을 소개하였다. 제서식 쏘일네일링 공법은 연직굴착시 가시설 흙막이벽체로 주로 사용할 수 있다. 제거식 쏘일네일의 인발특성을 규명하기 위해 총 23회의 현장인발실험을 실시하였으며, 이를 통해 고정자 소켓의 설치간격과 시멘트 그라우트의 W/C 비가 중요한 설계인자라는 것을 알 수 있었다. 또한 본 논문에서는 국내에서 처음으로 시공되는 제거식 쏘일네일 벽체의 설계 및 시공과 시공상태 등을 소개하였으며, 제거식 쏘일네일의 철근을 제거하기 전과 후에 벽체의 변형을 계측자료로부터 분석하였다.

• Journal of the Korean GEO-environmental Society
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• v.14 no.3
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• pp.19-27
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• 2013

Recently, the natural and man-made slope collapses occur frequently because of sudden heavy rains. So, a variety of slope reinforcement methods have been developed and applied to failure slopes. Soil nailing method usage has been increased because of its workability and economic aspects. This method has been applied in combination with other slope stability methods. Soil nailing method is a kind of combinational structure of steel bar and cement grouting. This method uses skin friction between adjacent ground and cement grouting to stabilize the slope. In this study, End-expanded soil nailing method was developed. This method consists of steel bar and anchor body attached at the tip of the nail. During construction, the anchor body at steel bar tip is settled to the ground through the expanding action. In this study, field pull-out tests were performed for un-grouting soil nailing and grouting soil nailing. From the test results, a wedge force of End-expanded soil nailing method was analyzed. And the behavior characteristics of End-expanded soil nailing were studied.

• Journal of the Korean GEO-environmental Society
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• v.11 no.3
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• pp.53-62
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• 2010

In the early 1990s, it was first introduced the soil nailing method for the slope stability and ground excavation and widely used as method of reinforcement. Also the application of soil nailing has been improved and 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, extension grout method. Three dimensional finite difference analysis was used to evaluate characteristics of pull-out behavior of extension grout method. In this paper, it was described a characteristics of pull-out behavior of soil nailing with extension grout method through the result of numerical method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.385-393
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• 2006

Soil nailing is a reinforcement method used for stabilizing excavated walls or slopes. Due to its much advantages such as ease of construction and economical efficiency, use of soil nailing is increased. However, the soil nail has much disadvantages for use in urban area. The soil nail needs to be installed inevitably beyond private land boundary, which causes rent for use. For this reason, removable soil nailing system was developed. However, the removal rate of this system is just about 50￠¦70%. To resolve this problem, the Fiber Reinforced Plastic (FRP) soil nailing system which does not need to be removed and allows for the installation beyond private land, is developed. In this paper, through theoretical and experimental studies in laboratory and field such as prototype tests, pullout tests, we evaluate the stability and behavior characteristics of the FRP soil nailing system. And, numerical analyses using FLAC2D were performed with respect to various soil conditions, where prototype test for excavation wall and pullout tests were carried out. As a result of this study, the FRP soil nailing systems show similar behavior characteristics with those of removable soil nailing system. Finally, considering the serviceability and mechanical stability of FRP soil nailing systems, it is enough to be used as a good alternative of general soil nailing system.

• Journal of the Korean GEO-environmental Society
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• v.9 no.4
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• pp.23-36
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• 2008

Soil nailing system can be mentioned to a method of supporting as the shear strength of in-situ soils is increased by passive inclusions. In the general soil nailing system, facing walls are used in two kind of a lattice concrete block or a cast in placed concrete wall. A case of lattice concrete blocks is used in slow slopes greater than 1(V):0.7(H). Also, a case of a cast in placed concrete wall is used in steep slopes less than 1(V):0.5(H). The cast in placed concrete walls are constructed to 30 cm thick together with a shotcrete facing. In this study, the assembling soil nailing method as a new soil nailing system will be proposed. This method is assembly construction using precast concrete panels with 20 cm thick. So, the ability of construction and the quality of facings can be improved more than a conventional soil nailing system. This method can be obtained the effects that a global slope stability increase, as precast concrete panels are immediately put on cutting face after excavating a slope. In this study, confining effects of concrete panels using the assembling soil nailing system were found out by large scaled load tests. In the tests, the load-settlement relationship to an assembling soil nailing system due to the stiff facings as concrete panels appeared to be better than a typical soil nailing system with shotcrete facings.

• Journal of the Korean GEO-environmental Society
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• v.9 no.3
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• pp.51-60
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• 2008

Soil nailing systems are generally many used to the temporary structure in underground excavations and reinforcements of slopes in Korea. However, large-scaled experimental studies related to soil nailing systems are mostly studies related to performance monitoring and field pullout tests. Specially, there are no researches related in the large scaled load tests of soil nailed walls in Korea. In this study, a case study on the large scaled load tests of soil nailed walls is introduced and the behavior characteristic of them is investigated. Also, they are proposed allowable deformation corresponding to the serviceability limit of soil nailed walls and ultimate deformation corresponding to the collapse state of the walls. These results can be applied to the maintenance management of soil nailed walls. And analysis on the required minimum factor of safety of soil nailed walls using the relation curve of load ratio and deformation ratio are carried out.

• Journal of the Korean Geotechnical Society
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• v.15 no.2
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• pp.105-127
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• 1999

Application of the soil nailing method is continuously extended in maintaining stable excavations and slopes. Occasionally, however, ground anchor support system may not be used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then, could play important roles in reducing deformations mainly in an upper part of the nailed-soil excavation system as well as improving local stability. In the present study, the analytical procedure and design technique are proposed to evaluate maximum pretension force and stability of the pretensioned soil nailing system. Also proposed are techniques to determine the required thickness of a shotcrete facing and to estimate probability of a failure against the punching shear. The predicted results are compared with the limited measurements obtained from the excavation site constructed by using the pretensioned soil nails. Based on the proposed procedure and technique, effects of the radius of a influence circle and dilatancy angle on the thickness of a shotcrete facing, bonded length and safety factors are analyzed. In addition, effects of the reduction of deformations expected by pretensioning of the soil nails are examined in detail throughout an illustrative example and FLAC$^{2D}$ program analysis.s.

• 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.