• Title/Summary/Keyword: 강도감소법

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A Study on Change of Safety Factor according to Slope Analysis Method using Strength Parameters and Slope Change (강도 정수와 경사도 변화를 활용한 비탈면 해석기법에 따른 안전율 변화에 관한 연구)

  • Moon, Hyojong;Shim, Jeonghoon;Jeong, Jisu;Lee, Seungho
    • The Journal of Engineering Geology
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    • v.27 no.1
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    • pp.31-40
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    • 2017
  • The slope stability analysis by the limit equilibrium method has the disadvantage that it can be applied only when the analysis is performed by setting the critical plane after analyzing the active surface many times and the soil is uniform and only the safety factor can be calculated. However, the analysis using the strength reduction analysis method has advantages that the engineer can judge various aspects and calculate the safety factor. In this study, the safety factor according to the change of slope and shear strength was compared and analyzed using limit equilibrium analysis and strength reduction method. It is suggested that it is desirable to use the strength reduction method which can synthetically review the stress, displacement, and strain in the soil.

Slope Stability Analysis Considering Seepage Conditions by FEM Using Strength Reduction Technique (강도 감소법에 의한 지하수위를 고려한 FEM 사면안정해석)

  • 김영민
    • Journal of the Korean Geotechnical Society
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    • v.20 no.8
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    • pp.97-102
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    • 2004
  • In this paper, a finite element based method far determining factor of safety of slopes which has certain advantages over conventional limit equilibrium methods is described. Particularly, the slope failure behaviour considering different seepage conditions is produced by finite element method using strength reduction technique. It is shown that both the failure mechanism and the safety factor that are analyzed by the FEM using strength reduction technique are an effective means of slope stability analysis. And the stability of a slope with rising water table and rapid drawdown are analyzed and the results are compared with the simplified Bishop Method of the Limit Equilibrium Methods.

Stability Analysis of Rock Slope in Limestone Mine by Numerical Analysis (수치해석에 의한 석회암 채굴 사면의 안정성 해석)

  • 임한욱;김치환;백환조
    • Tunnel and Underground Space
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    • v.11 no.3
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    • pp.270-278
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    • 2001
  • Two numerical methods such as DEM and FDM were adopted to analysis of rock slope stability, of which dimensions are about 150 m(length), 58 m(height), 70°dip, in Halla limestone mine. For this rock slope stability analysis, strength reduction method was used to calculate the safety factor of slope through numerical method. To keep the rock slope safely, it is proposed to reduce the height of the rock slope from 58 m to 45 m and to reduce the angle of the slope from 70°to 55°, too.

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Comparative Study of LEM and SSR-FEM on Stability of Reinforced Soil Slope (보강토사면의 안정성에 대한 LEM과 SSR-FEM의 비교연구)

  • Kim, Young-Min;Kang, Seong-Gwi
    • Journal of the Korean Geosynthetics Society
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    • v.8 no.1
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    • pp.11-18
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    • 2009
  • This paper presents a comparative study of reinforced soil slope by using LEM and SSR-FEM. Current analysis methods for reinforced soil wall are based on LEM. SSR-FEM assumes a reduction of soil strength by a factor to reach a critical state prior to failure based on continuum mechanics. In this study the comparisons are concerned with the factor of safety and the potential failure surface in reinforced soil wall. We investigated the stability of the reinforced soil wall with a slope of $60^{\circ}$ by LEM and SSR-FEM. The comparisons indicated good performance of the SSR-FEM on stability analysis of reinforce soil wall.

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Slope Stability Charts of Soil Nailing Method for Slope Diaster Prevention (사면재해 방지를 위한 Soil Nailing 공법의 사면안정 도표)

  • Kim, Ji-Seong;Ku, Mi-Ok
    • The Journal of the Korea Contents Association
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    • v.16 no.7
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    • pp.457-464
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    • 2016
  • The analysis for stability of slope reinforced with soil nails need professional knowledge and skilled technology for program. So we spend a lot of money and time. In this study, we try to save it. After we analyzed the stability of reinforced slope with MIDAS GTS using shear strength reduction technique, we made charts by result. Charts created in the stydy can be used rapidly in slope disaster prevention. We try to analyze stability of slopes when we changed nail spacing, nail angle, slope type, properties of soil. We obtained relationship as follows; 1) The safety factor appears effectively when the nail angle is $10{\sim}20^{\circ}$. 2) The safety factor appears effectively when the nail spacing is 0.8~1.2m. 3) The error of Singh's and suggested chart are 3.45, 8.65, 4.35% when the slope are 1:0.5, 1:1, 1:2.

Numerical Study on the Optimal Shape of Concrete Plug for Compressed Air Energy Storage Caverns (압축공기에너지 저장 공동의 콘크리트 플러그 최적 형상에 대한 수치해석적 연구)

  • Park, Doh-Hun;Kim, Hyung-Mok;Ryu, Dong-Woo;Synn, Joong-Ho;Song, Won-Kyong
    • Tunnel and Underground Space
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    • v.21 no.3
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    • pp.164-173
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    • 2011
  • In the present study, the stability of a compressed air energy storage cavern was numerically assessed by concrete plug shapes in order to investigate the optimal shape of concrete plug. The concrete plugs were cylindrical, embedded cylindrical, tapered, and wedged in shape. The stability assessment was carried out based on factor of safety through a strength reduction method and a volume ratio which refers to the ratio of the volume of yield regions in concrete induced by internal pressure to all concrete volume. The results from the present study indicated that the embedded cylindrical and taper shaped plugs were mechanically more stable than the cylindrical and wedge shaped plugs. However, from a comparison of stress distributions in rock mass between the embedded cylindrical and taper shaped plugs, the taper shaped plug was found to be more optimal than the embedded cylindrical plug, since the embedded cylindrical plug caused more stress concentration in the interface between the plug and rock mass than the taper shaped plug.

Numerical Design Approach to Determining the Dimension of Large-Scale Underground Mine Structures (대규모 지하 광산 구조물의 규모 결정을 위한 수치해석적 설계 접근)

  • Lee, Yun-Su;Park, Do-Hyun;SunWoo, Choon;Kim, Gyo-Won;Kang, Jung-Seok
    • Tunnel and Underground Space
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    • v.22 no.2
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    • pp.120-129
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    • 2012
  • Recently, mining facilities have being installed in an underground space according to a social demand for environment-friendly mine development. The underground structures for mining facilities usually requires a large volume of space with width greater than height, and thus the stability assessment of the large-scale underground mine structure is an important issue. In this study, we analysed a factor of safety based on strength reduction method, and proposed a numerical design approach to determining the dimension of underground mine structures in combination with a strength reduction method and a multivariate regression analysis. Input design parameters considered in the present study were the stress ratio and shear strength of rock mass, and the width and cover depth of underground mine structures. The stabilities of underground mine structures were assessed in terms of factor of safety under different conditions of the above input parameters. It was calculated by the strength reduction method, and several kinds of fit functions were obtained through various multivariate regression analyses. Using a best-fit regression model, we proposed the charts which provide preliminary design information on the dimension of underground mine structures.

An Assessment of Safety Zone for Mountain Tunnel Portal Using Strength Reduction Technique (강도감소법을 이용한 산악터널 갱구부의 안전영역 평가)

  • Hong, Chang-Soo;Hwang, Dae-Jin;Lee, Kang-Ho;You, Kwang-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.925-930
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    • 2006
  • During the excavation of a tunnel portal, failure zones around the tunnel heading occur and also the ground supports itself. In a portal, its location and the ground characteristic have a great influence on the stability of the tunnel. Therefore, the failure mechanism of a tunnel heading and how to assess the stability of the tunnel are very important. In this paper, the numerical analyses were executed to evaluate the safety factor using strength reduction technique. The influence area of an excavation was also predicted through a case study in which no-support case and support case with the Pattern P-6 were compared in terms of the ground class and the shear strain.

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Stability Assesment of the Slope at the Disposal Site of Waste Rock in Limestone Mine (석회석 광산에서 폐석 적치장 사면의 안정성 평가)

  • Lee, Sang-Eun;Jang, Yoon-Ho
    • Tunnel and Underground Space
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    • v.20 no.6
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    • pp.475-490
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    • 2010
  • The analysis of slope stability was performed from seven sites among total eleven sites of waste rock which are divided into two objects (mullock-pile and rock mass) according to the location of dumping-dropping point in L limestone Mine. The analysis of circular failure using Bishop's simplified method and the finite element method for mullock-pile slopes were adopted. For rock mass slopes, identification of failure modes on stereonet projection was determined, thereby limit equilibrium analysis was applied to obtain the safety factor of slopes and the finite element method was used to understand overall behavior of slope. Phi-c reduction method was used to calculate the safety factor of slopes through the finite element method. In mullock-pile slope of zone D and rock slopes of zone F and G, the assurance of slope stability was difficult, and the plans to assure the stability of slopes were proposed on the basis of the analysis of slopes at disposal sites of waste rock. Therefore, the method of piling with waste rock by dozer pushing after dumping for mullock-pile slope of zone D is required, and the method of piling after moving to the place which has no fault zone for rock slope of zone F and G is recommended.

Stability Analysis of Embankment Slopes Consisting of Rock Fragments (암석 버력으로 성토한 사면의 안정성 해석)

  • 김치환
    • Tunnel and Underground Space
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    • v.12 no.2
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    • pp.83-91
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    • 2002
  • Stability analysis of rocky embankment slopes is done by both the limit equilibrium method and the finite difference method. The height or the rocky embankment is approximately 40 m and the side slope is 1 vertical to 1.5 horizontal. The cohesion and internal friction angle of rock debris are assumed zero and 43$^{\circ}$, respectively. For finite difference analysis, strength reduction method is used to calculate the saft factor of the slope. As a result, the safety factor of the slope is discovered to be 1.4 by using either methods. Considering that the design criteria of the safety factor is 1.3, it can be judged that the rock fragments embankment slope is in a stable state.