• Title/Summary/Keyword: The soil nailing

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A Study on the Stability and Behavior of upward Soil-nailing (상향으로 설치된 쏘일네일링의 안정성 및 거동에 관한 연구)

  • Kim, Jae-Yoon;Lee, In;Choi, Geun-Hyeok;Kim, Hong-Taek
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.1086-1091
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    • 2009
  • The purpose of this study is to provide the technical information of the stability change and behaviour characteristics in case upward direction of soil nailing is installed. Generally, the soil nailing which installed in case of vertical excavation or for the purpose of the slope stability is installed between 5 to 15 degree of downward direction. The downward direction of the soil nailing method has lots of advantages such as the increase of the stability, the convenience of the grout compared to upward direction of soil nailing. Even though the upward direction of the soil nailing has the disadvantages in terms of the stability and the grout construction, horizontal displacement tends to be decreased.

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Influence of Facing Stiffness on Global Stability of Soil Nailing Systems (전면벽체의 강성이 Soil Nailing 시스템의 전체안정성에 미치는 영향)

  • Kim, Hong-Taek;Kang, In-Kyu;Kwon, Young-Ho
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.3
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    • pp.51-60
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    • 2004
  • In Korea there are recently many attempts to expand a temporary soil nailing system into a permanent soil nailing system since the first construction in 1993. In the soil nailing system, the rigid facing walls act on restraining the deformation of the ground. These are purposed to minimize the damage of adjacent buildings or underground structures. In Korea, to minimize the relaxation of the ground, the soil nailing system in the downtown area is often used experientially together with braced cuts, sheet pile walls, soil cement walls (SCW), or jet grouting walls. However, for the conservative design, the confining effects by the stiff facing have been ignored because the proper design approach of considering the facing stiffness has not been proposed. In this study, various laboratory model tests are carried out to examining the influence the rigidity of facings on the global safety of soil nailing system. Also, the parametric studies using the numerical technique as shear-strength reduction technique are carried out. In the parametric study, the thickness of concrete facing walls is changed to identify the effects of the facing wall stiffness.

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Influence of Facing Stiffness on Global Stability. of Soil Nailing Systems (전면벽체의 강성이 Soil Nailing 시스템의 전체안정성에 미치는 영향)

  • Kim, Hong-Taek;Kwon, Young-Ho;Kang, In-Kyu;Park, Sa-Won;Kang, Yun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.427-434
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    • 2002
  • In Korea, there are recently many attempts to expand a temporary soil nailing system into a permanent soil nailing system since the first construction in 1993. In the downtown area, it is important that the relaxation of the ground is minimized in the ground excavation works. Due to these problems, soil nailing systems are often used the flexible facing such as shotcrete rather than the rigid facing such as SCW, CIP, and jet grout types in Korea. The soil nailing systems with rigid facings are used greatly however it is insufficient researches for design and analysis of soil nailing systems with rigid facings. In this study, various laboratory model tests are carried out to examining the influence the rigidity of facings on the global safety of soil nailing system, failure loads, displacement behaviour, axial force acting on the nails, and distribution of earth pressure. Also, the parametric studies are carried out for the typical section of soil nailed walls according to thickness of concrete facings and internal friction angle of soil using the numerical technique as shear strength reduction technique.

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An Estimation on the Applicability of Hollow FRP Soil Nailing System (중공식 FRP쏘일네일링 시스템의 적용성 평가)

  • Kim, Hong-Taek;Lee, Hyuk-Jin;Jung, Woo-Chul;Koh, Hyung-Seon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.1014-1023
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    • 2006
  • Soil nailing is a reinforcement method used for stabilizing excavated wall or slope. Due to its many advantages such as ease of construction and economical efficiency, use of soil nailing is increased. However, the soil nail can't trespass on the neighbor private land, which pays rent for use. For this reason, removable soil nailing system was developed. However, the removal rate of this system is just about $50\sim70%$. To solve this, the Fiber Reinforced Polymer (FRP) soil nailing system, which does not need to be removed and allows for the trespass on the private land, is developed. In this paper, through theoretical and experimental studies in laboratory and field, we evaluate the stability and behavior characteristics of the FRP nail system. Besides, numerical analyses using FLAC2D were performed for various soil conditions, where the simulations for pullout tests were carried out. As a result, compared with the conventional removable soil nailing system, the FRP soil nailing systems show similar behavior characteristics.

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Probabilistic optimization of nailing system for soil walls in uncertain condition

  • Mitra Jafarbeglou;Farzin Kalantary
    • Geomechanics and Engineering
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    • v.34 no.6
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    • pp.597-609
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    • 2023
  • One of the applicable methods for the stabilization of soil walls is the nailing system which consists of tensile struts. The stability and safety of soil nail wall systems are influenced by the geometrical parameters of the nailing system. Generally, the determination of nailing parameters in order to achieve optimal performance of the nailing system for the safety of soil walls is defined in the framework of optimization problems. Also, according to the various uncertainty in the mechanical parameters of soil structures, it is necessary to evaluate the reliability of the system as a probabilistic problem. In this paper, the optimal design of the nailing system is carried out in deterministic and probabilistic cases using meta-heuristic and reliability-based design optimization methods. The colliding body optimization algorithm and first-order reliability method are used for optimization and reliability analysis problems, respectively. The objective function is defined based on the total cost of nails and safety factors and reliability index are selected as constraints. The mechanical properties of the nailing system are selected as design variables and the mechanical properties of the soil are selected as random variables. The results show that the reliability of the optimally designed soil nail system is very sensitive to uncertainty in soil mechanical parameters. Also, the design results are affected by uncertainties in soil mechanical parameters due to the values of safety factors. Reliability-based design optimization results show that a nailing system can be designed for the expected level of reliability and failure probability.

An Experimental Study on Behavior Characteristic of the Soil Nailed Wall with Facing Stillness (전면벽체 강성에 따른 쏘일네일링 벽체의 거동특성에 관한 실험적 고찰)

  • 김홍택;강인규;권영호;조용훈
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.279-286
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    • 2002
  • Recently, there are many attempts to expand a temporary soil nailing system into a permanent wall due to the advantage of soil nailing system, that is efficient and economic use of underground space and decreasing the total construction cost. However, the proper design approach of a permanent soil nailing system has not been proposed by now in Korea. Permanent soil nailing system which utilizes precast concrete walls for the facing of soil nailing system Is already used in many countries. In general, the cast-in-place concrete facings or rigid walls were constructed in bottom-up way after construction of soil nailing walls finished preliminarily In this paper, various laboratory model tests have been carried out to investigate the failure mode, behavior characteristics, and tensile force at nail head in each load level in respects of the variation of stiffness of the facing.

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Design Case Study of Permanent Excavation Wall Using Soil Nailing System (쏘일네일링 공법을 적용한 영구 지하굴착 벽체의 설계사례 연구)

  • Park, Si-Sam;Lee, Je-Man;Yoo, Chan-Ho;Kim, Hong-Taek
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.84-91
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    • 2005
  • In case of soil nailing system, there have been many attempts to expand into slope and temporary earth retaining system stabilization method since the first ground excavation earth retaining system construction in 1993. Recently, jointing wall, underground wall of buildings and excavation earth retaining wall, construction were increasingly applied for effective utilization of the limited underground space and land application maximized. However, the application of joining wall into retaining wall or building by temporary soil nailing system and design of permanent wall were performed by using Rankine earth pressure theory without considering the distribution of earth pressure in the soil nailing. In this study was performed to introduce the design case by 'Two-Body Translation mechanism (TBTM)' to be able to consider distribution of earth pressure in the soil nailing when designing the permanent jointing wall using soil nailing system for effective utilization of ground space. Also, this study attempts to evaluate the earth pressure change, decreasing effect of wall displacement and increasing effect of stability when advanced soil nailing system is constructed using $FLAC^{2D}$ ${\nu}er.$ 3.30 program and 'Two-Body Translation mechanism'.

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An Estimation of Wedge Type Removable Soil Nailing System Using by Laboratory Tests (실내역학 실험을 통한 쐐기형 제거식 쏘일네일링 공법의 적용성 평가)

  • Park, Si-Sam;Han, Yeon-Jin;Heo, Seong-Jun;Yoon, Myung-June;Kim, Hong-Taek;Park, Ju-Seok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.1330-1333
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    • 2009
  • The soil nailing method had used in variable construction field because of construction convenience and reinforcement effect. Especially, the removal soil nailing method is useful support system in vertical excavation. In this study, to develop the wedge type removable soil nailing method for improvement of the removal soil nailing method. Because of the reinforcement materials is most important in soil nailing method, to evaluate the mechanical characteristics during laboratory strength test in this study. To conduct bond strength test of deformed bar combined with a wedged screw inside plastic fixed socket for evaluate the strength characteristics of wedge type removable soil nailing method and evaluate the strength characteristics of fixed socket based on laboratory tests.

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The Development of End-expanded Soil Nailing Method for Ground Reinforcement and its Behavior Characteristics (선단확장형 쏘일네일링 공법 개발과 거동특성 분석)

  • Moon, Hongduk;Jung, Youndug
    • 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.

A Case Study on Construction and Design of the Wedge Type Removable Soil Nailing System (쐐기형 제거식 쏘일 네일링 시스템의 설계 및 시공사례)

  • Han, Yeon-Jin;Park, Si-Sam;Kwon, Hyuk-Jun;Kim, Hong-Taek;Park, Ju-Seok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.240-247
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    • 2010
  • The soil nailing system is becoming common as reinforcement method of slope face in soil. It has application to obtain slope stability method and scaffolding system. It has some troubles when the soil nailing system is applied to the downtown because it could be invaded someone's private area. Thus, in this paper, wedge type removable soil nailing system which can easily remove deformed bar in final excavation step is developed. Field pull-out test is performed to evaluate deformed bars removal and pullout resistance characteristics. According to this result, application of Wedge Type Removable Soil Nailing System is performed.

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