• Title/Summary/Keyword: limit equilibrium analysis

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Comparison of Safety factor for an Anchored Slope in Accordance with the Effects of Load Transfer (앵커 하중전이에 따른 사면의 안전율 비교 연구)

  • Kim, Sung-Kyu;Kim, Wak-Kyung;Park, Jong-Sik;Joo, Yong-Sun;Kim, Tae-Hoon
    • Journal of the Korean Geotechnical Society
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    • v.24 no.11
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    • pp.55-60
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    • 2008
  • This paper presents how the load transfer mechanism of the ground anchor affects on the stability analysis of anchored slope. The finite element analysis and the conventional limit equilibrium analysis on the anchored slope were performed and compared. The limit equilibrium analysis of the anchored slope is widely used in design practice due to the easiness of the analysis. However, the load transfer mechanism is not considered properly for the analysis. When the failure surface passes through the bonded length of an anchor, the anchor load is disregarded and the factor of safety for the anchored slope is smaller than it should be. In this study, the load transfer distribution was incorporated into the limit equilibrium stability analysis of the anchored slope and the results were compared with those of finite element analysis.

Study on Characteristics of Numerical Analysis Method for Stability Analysis of Reinforced Slope (보강사면의 안정해석을 위한 수치해석방법의 특성에 관한 연구)

  • Kim, Joon-Seok;Kim, Ju-Yong
    • Journal of the Korean Geosynthetics Society
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    • v.8 no.3
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    • pp.17-23
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    • 2009
  • Conventional methods of reinforced slope analysis based on the concept of limit equilibrium have been widely adopted mainly due to their simplicity and short computation time. But depending upon the assumptions on the inter-slice forces, the factor of safety resulting from the limit equilibrium method is not uniquely determined. This paper describes a method to calculate the factor of safely of a slope using a numerical analysis. Recently some useful analysis techniques (Strength reduction method and the stability method using stress fields) by numerical analysis are proposed and their theory and characteristics applications are studied and investigated with simple examples in this paper.

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Limit Equilibrium, Finite Difference, and Finite Element Analysis of Slopes (한계평형해석(LEM), 유한차분법(FDM) 및 유한요소법(FEM)을 이용한 사면안정해석)

  • Jeon, Sang-Soo;Lee, Choong-Ho;Oh, Mi-Hee;Gang, Sang-Wook;Pham, Nguyeon Quoc;Kim, Doo-Seop
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.199-206
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    • 2005
  • Engineers have performed slope stability analyses, including Limit Equilibrium Analysis, Finite Difference Analysis and Finite Element Analysis. Each analysis results in different Factor of Safety(FS) for slopes. The comparison of FS results from these stability analyses has been carried out for various conditions, such as geometry of slopes, dry and fully saturated soils, nail and anchor reinforcements. Standard deviations of FS calculated from various slope analyses are 0.03 to 0.04 and 0.22 to 0.48 for the slopes without and with nail or anchor reinforcement, respectively. Construction of tiered concrete retaining wall in addition to nail or anchor reinforcement increases FS of 12% to 29% for fully saturated soils.

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A Study on the Stability Analysis of Rock Slope located near Andong-si (안동시 OO지역 암반사면의 안정해석에 관한 연구)

  • Park, Sung-Kwon;Kim, Ki-Bum;Jung, Dong-Young;Lee, Yoon-Gyu;Baek, Seung-Cheol
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.561-564
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    • 2008
  • Rock slope had been slope failure due to geological and physical things over time. In this paper, it discusses rock slope stability analysis which was concerned about additional slope failure located near the Andong-si. Initially, achieved basic geological investigation and field test about rock slope, examine the stability of rock slope by doing limit equilibrium method and stereographic projection about 5 slopes.

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Development of limit equilibrium method as optimization in slope stability analysis

  • Mendjel, D.;Messast, S.
    • Structural Engineering and Mechanics
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    • v.41 no.3
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    • pp.339-348
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    • 2012
  • The slope stability analysis is usually done using the methods of calculation to rupture. The problem lies in determining the critical failure surface and the corresponding factor of safety (FOS). To evaluate the slope stability by a method of limit equilibrium, there are linear and nonlinear methods. The linear methods are direct methods of calculation of FOS but nonlinear methods require an iterative process. The nonlinear simplified Bishop method's is popular because it can quickly calculate FOS for different slopes. This paper concerns the use of inverse analysis by genetic algorithm (GA) to find out the factor of safety for the slopes using the Bishop simplified method. The analysis is formulated to solve the nonlinear equilibrium equation and find the critical failure surface and the corresponding safety factor. The results obtained by this approach compared with those available in literature illustrate the effectiveness of this inverse method.

Upper Bound Limit Analysis of Bearing Capacity for Surface Foundations on Sand Overlying Clay (점토층위의 모래지반에 위치한 얕은 기초의 지지력에 대한 상한 한계해석)

  • 김대현;야마모토켄타로
    • Journal of the Korean Geotechnical Society
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    • v.20 no.3
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    • pp.85-96
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    • 2004
  • The ultimate bearing capacity of surface foundations on a sand layer overlying clay has been theoretically investigated. First, a review of previous studies on the bearing capacity problems for this type of foundation was performed and a discussion was presented concerning the practical application. Second, the kinematic approach of limit analysis was used to calculate the upper bound of the true ultimate bearing capacity. The kinematic solutions are upper bounds and their accuracy depends primarily on the nature of the assumed failure mechanism. This approach makes it convenient to create design charts, and it is possible to trace the influence of parameters. Third, the commercial finite element program ABAQUS was applied to obtain the ultimate bearing capacity based on the elasto-plastic theory. Results obtained from the kinematic approach were compared with those from the program ABAQUS and the limit equilibrium equations proposed by Yamaguchi, Meyerhof and Okamura et al. Finally, the validities of the results from the kinematic approach, the results from the program ABAQUS and the limit equilibrium equations were examined.

Analysis for Effects of Slope Failure Behavior by Finite Element Method (유한요소법에 의한 사면붕괴 거동해석에 미치는 영향분석)

  • 김영민
    • Journal of the Korean Geotechnical Society
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    • v.15 no.5
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    • pp.19-28
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    • 1999
  • In this paper, an application of finite element procedure for the analysis of slope failure behavior has been studied. The most widely accepted methods in analyzing the slope stability problems are mostly based on limit equilibrium method. And the finite element method is widely accepted to analyze stress and displacements. This paper shows how the factor of safety calculated in the finite element method can be systematically incorporated into slope stability. In analyzing the slope failure behavior by finite element method, the effects of computational method and the results have been discussed. And several computations of slope stabilities were carried out to compare the finite element analysis results with those obtained by methods of slices based on the limit equilibrium analysis.

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Static and quasi-static slope stability analyses using the limit equilibrium method for mountainous area

  • Hosung Shin
    • Geomechanics and Engineering
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    • v.34 no.2
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    • pp.187-195
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    • 2023
  • Intensive rainfall during the summer season in Korea has triggered numerous devastating landslides outside of downtown in mountainous areas. The 2D slope stability analysis that is generally used for cut slopes and embankments is inadequate to model slope failure in mountainous areas. This paper presents a new 3D slope stability formulation using the global sliding vector in the limit equilibrium method, and it uses an ellipsoidal slip surface for static and quasi-static analyses. The slip surface's flexibility of the ellipsoid shape gives a lower FS than the spherical failure shape in the Fellenius, Bishop, and Janbu's simplified methods. The increasing sub-columns of each column tend to increase the FS and converge to a steady value. The symmetrical geometric conditions of the convex turning corners do not indicate symmetrical failure of the surface in 3D analysis. Pseudo-static analysis shows that the horizontal seismic force decreases the FS and increases the mass volume at the critical failure state. The stability index takes the FS and corresponding sliding mass into consideration to assess the potential risk of slope failure in complex mountainous terrain. It is a valuable parameter for selecting a vulnerable area and evaluating the overall risk of slope failure.

A Study on the Stability Evaluation of Soil Slope according to inclination of upper Natural Slope (상부자연사면 경사에 따른 토사사면의 안정성 평가에 관한 연구)

  • Lee, Jeong-Yeob;Kim, Jin-Hwan;Lee, Jong-Hyun;Gu, Ho-Bon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.580-585
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    • 2004
  • The purpose of this study is the stability evaluation of soil slope according to inclination of upper natural slope. Upper natural slope breeds loss of slope by inflow in slope of surface water by rainfal1 and f1uctuation of amount of materials in slope through method of cutting slope according to degree of inclination. Basis of standard inclination does not consider of inclination of upper natural slope and is presented uniformly. Therefore, in this study, analyzed stability of inclination of upper natural slope through limit equilibrium analysis. Result is same as following. First, safety factor through limit equilibrium analysis is almost direct decrease when gradient of soil slope is 1:1.2, 1:1.5. However, when gradient of soil slope is 1:1.0, 1:0.7, if sinclination of upper natural slope are $20^{\circ}$, it shows tendency that decrease of safety factor becomes low rapidly. Second, when when gradient of soil slope is fixed, inclination of upper natural slope increase tendency(maximum 3.0 times) that decrease of safety factor.

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Stability Analysis of Pile/Slope Systems Considering Pile-slope Interaction (억지말뚝-사면의 상호작용을 고려한 사면안전율 분석)

  • 김병철;유광호;정상섬
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.513-520
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    • 2003
  • A numerical comparison or predictions by limit equilibrium analysis and 3n analysis is presented for slope/pile system. Special attention is given to the coupled analysis based on the explicit-finite-difference code, FLAC. To this end, an internal routine (FISH) was developed to calculate a factor of safety for a pile-reinforced slope according to shear strength reduction technique. The case of coupled analyses was performed for stabilizing piles in slope in which the pile response and slope stability are considered simultaneously and subsequently the factors of safety are compared to uncoupled analysis (limit equilibrium analysis) solution for a homogeneous slope. Based on a limited parametric study, it is shown that in the free-head condition the factor of safety in slope is more conservative for a coupled analysis than for an uncoupled analysis and a definitely larger value represents when piles are installed in the middle of the slopes and are restrained in the pile head.

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