• Title/Summary/Keyword: 사면 보강

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Analysis of the Stability and Behavior of a Calcareous Rock Slope During Construction of a Tunnel Entrance (터널출입구 시공에 따른 석회암 사면의 안정성 및 거동 분석)

  • Song, Young-Suk;Yun, Jung-Mann
    • The Journal of Engineering Geology
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    • v.23 no.3
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    • pp.283-292
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    • 2013
  • A calcareous rock slope failed during excavation of the slope for construction of a tunnel entrance. The slope is located at the construction site for widening highway in Yeongwol, Korea. Field surveys, laboratory tests, and numerical analyses were performed to determine the reason for the slope failure. The numerical analysis revealed that the safety factor of the slope before construction of the entrance was less than 1, and that this decreased after construction. After construction of the entrance, the sliding zone of the slope increased and slope stability decreased because the shear strain and plastic zone in the slope over the tunnel entrance showed an increase relative to the lower part of the slope. To enhance the stability of the slope for construction of the tunnel entrance, countermeasures such as rock bolts, rock anchors, and FRP (Fiber glass Reinforced Plastic) grouting were adopted in light of the field conditions. Serial field monitoring performed to confirm the reinforcing effects of the adopted countermeasures revealed a small amount of horizontal deformation of the slope soils, most of the elastic deformation that can regain its former value. In addition, the axial forces of the rock bolt and anchor were more strongly affected by slope excavation during construction of the tunnel entrance than by tunnel excavation or the rainy season, and the axial forces tended to converge after excavation of the tunnel. Therefore, we can confirm that the slope is currently safe.

A Case Study on Solpe and Earth Retaining Wall Reinforced by Pressure-Grouted Soil Nailing (압력식 쏘일네일링을 적용한 사면 및 흙막이 벽체 설계/시공 사례)

  • Jung, Kyung-Han;Kim, Jun-Youp;Lee, Seung-Jai
    • 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.

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A Study on the Safety Ratio of Reservoir Embankment by Seismic Reinforcement Section Shape (내진보강 단면형상에 따른 국내 저수지 제방의 안전율에 대한 검토)

  • Lim, Seonghun;Kim, Daehyeon
    • The Journal of Engineering Geology
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    • v.31 no.3
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    • pp.343-355
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    • 2021
  • Agricultural reservoirs seek human convenience by supplying agricultural water and providing flood damage effects and rest areas at the same time, but preventing them from aging reservoirs and earthquakes is important. The safety of levees is influenced by field material properties such as soil parameter values of the granular materials that make up the levees, but since precision safety diagnosis or general literature values are diverted, the final safety factors are limited to material properties alone. Since safety factors are determined by physical characteristic values and embankment shapes and have a significant impact on safety factors, accurate contemplation is required when examining reinforced cross sections. Therefore, this study analyzed the case of reasonable and economical reinforcement intersections when designing '◯◯reservoir' in Goheung-geun, Jeollanam-do using the GEP-SLOPE program to enable rational economic design of reinforcement intersections through repeated reviews. As a result of reducing and analyzing the first, second, and third seismic reinforcement of the levees, it was confirmed that the safety ratio was secured even with a significantly smaller amount of reinforcement than the first, second, and lower slopes by obtaining design standards of 1.20. In addition, when determining all seismic reinforcement cross-sectional shapes, it was confirmed that the shape that reinforces only the lower side rather than the upper side of the slope and the entire slope was economical with minimized cross-sectional reinforcement.

Estimation of Slope Behavior by Soil Temperature (지중온도에 의한 사면의 거동 예측)

  • 장기태;한희수;유병선
    • Journal of the Korean Geotechnical Society
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    • v.19 no.6
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    • pp.407-418
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    • 2003
  • It is necessary, in the light of the importance of long-term slope stability problem, to develop a simple method or tool which can figure out the possible failure surface resulting from weathering effect and other factors. The FBG(Fiber Bragg Crating) sensor system is used to estimate the correlations between the soil temperature and the slope behavior, and to find a failure surface in slopes effectively. This research is to seek for the correlation between the soil temperature distribution and the strain distribution of the reinforcing materials in an active zone by analyzing the data from the in-situ measurement so that the possible failure surface should be well defined based on the correlation. The zone of high temperature fluctuation can be regarded as one of the possible failure surface due to the weathering effect while the constant temperature depth of the ground, if exists, would not be relatively affected by the weathering process.

An Experimental Study on the Effect of Vegetation Roots on Slope Stability of Hillside Slopes (뿌리의 강도가 자연사면 안정에 미치는 영향에 관한 실험연구)

  • Lee, In-Mo;Seong, Sang-Gyu;Im, Chung-Mo
    • Geotechnical Engineering
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    • v.7 no.2
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    • pp.51-66
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    • 1991
  • In the stability analysis of hillside slopes, the roots of vegetation have been considered to act as a soil reinforcement. In order to predict the amount of increase in soil shear resistance, produced by tensile strength of roots that intersect a potential slip surface in hillside slopes, new soil -root interaction models are proposed in this paper. For this purpose, firstly, laboratary teats and in-situ tests wert performed on soil-root systems, and experimental results were compared with a couple of soil-root interaction models which had been proposed by Gray, Waldron, and Wu etc. Based on this comparison, a new soil-root interaction model is proposed. Secondly, a probabilistic soil-root model is proposed based on statistical analysis considering random nature of root distribution, root characteristics, and soil-root interactions. Finally, to examine the effect of this root reinforcement system on stability of hillside slopes, a simple three-dimensional stability analysis was performed, and it was shown that root reinforcement had a significant stabilizing influence on shallow slips rather than deep slips in hillside slopes.

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Stability Analysis and Design of Slope Reinforcing Method Using Anchored or Waste Tyre Wall (앵커 또는 폐타이어 벽체를 이용한 사면보강공법의 안정해석 및 설계)

  • 김홍택;강인규
    • Geotechnical Engineering
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    • v.10 no.2
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    • pp.69-84
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    • 1994
  • In the present study, the application of a method of anchored or waste tyre wall in reinforcing the unstable slope is investigated. For design purposes a method of external stability analysis of the reinforced slope, together with a method of internal stability analysis of a wall itself, is presented. In order to predict the passive resistance expected in the anchor or waste tyre Meyerhof's bearing capacity theory is moapaed and experimental results of stress distribution of a pile section under lateral loading is used. Hurray's pull-out teat results are compared with the passive resistances of anchors predicted by the proposed method, and alto the advantages in design are compared with a method of reinforced earth wall with steel strips. Finally a design example of reinforced slope using anchored or caste tyre wall is presented and the overall stability is analyzed in detail by the proposed method of analysis. The efficiency of a method of anchored or waste tyre wall is further analyzed, comparing with a method of changing geometry of the origin리 unstable slope.

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Determination Technique of Cut-Slope Reinforcing Method Considering the Effect Factor (영향인자를 고려한 절토사면 보강공법 선정기법)

  • Han, Jung-Geun;Lee, Jong-Young;Lee, Myung-Ho;Choi, Poong-Kon
    • Journal of the Korean Geosynthetics Society
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    • v.6 no.2
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    • pp.27-32
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    • 2007
  • Analysis was performed using AHP (Analytic Hierarchy Process) technique for the determination of priority on the effect factors and the preferences on cut-slope reinforcing methods. The results from professional group, such as researchers, design engineers and construction engineers, show that stability, durability and environmental condition are the most important effect factors. The retaining wall and the cutting methods were predominant for stability, economical efficiency, and maintenance/management in the evaluation of preferences on the cut-slope reinforcing methods interpreted for the increasing method of safety factor.

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Development of Improved Rock Bolt for Reinforcement of Fracture Zone in Slope and Tunnel (사면 및 터널에서의 암반 파쇄대 보강을 위한 개량형 록볼트 개발)

  • Kim, Soo-Lo;Kim, Jong-Tae;Park, Seong-Cheol;Kim, Tae-Heok;Kwon, Hyun-Ho;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.20 no.1
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    • pp.101-109
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    • 2010
  • There are many slopes generally developed by excavation and cut slope with small steps on massive slopes of roads. Especially these cut slopes which excavating around fault fracture zone need a reinforcement technology in order to ensure safety. In the case of slope excavation, it is difficult to use the existing slope support at fracture zone because of geological characteristics. Especially the factor of safety decreases significantly due to the movement of blocks in bed rocks and the expansion of interspace of discontinuous planes in fractured zones caused by excavation. Thus an efficient reinforcement technique in accordance with geological properties of fracture zones needs to be developed because the existing slope support has a restricted application. Therefore it is necessary to develop the specialized rock bolt technique in order to ensure an efficient factor of safety for anomalous fracture zones in slopes and tunnels. The purpose of this study is to develop newly improved rock bolt to increase a supporting effect of the swellex bolt method used recently as a friction type in fracture zones.

Influence of Soil Nailing Angle on Slope Reinforcement Effect by Finite Difference Analysis (유한차분해석을 통한 쏘일네일링 설치각도가 사면 보강효과에 미치는 영향)

  • You, Kwang-Ho;Min, Kyoung-Sun
    • 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.