• Title/Summary/Keyword: equilibrium factor

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An Assessment of Safety Factor for Tunnels Excavated in a Weak Rock Layer (연약 암반층에 굴착된 터널의 안전율 평가)

  • You, Kwang-Ho;Park, Yeon-Jun;Bae, Gyu-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.2 no.3
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    • pp.47-57
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    • 2000
  • It is difficult to calculate factor of safety of a tunnel by applying any analytical method based upon limit equilibrium method since the shape of failure plane in tunnel analysis can not be easily assumed in advance. To cope with this shortcoming, a method is suggested to calculate safety factor of a tunnel by numerical analysis using strength reduction technique. A circular tunnel excavated in a homogeneous rock was selected as an example problem and factors of safety were calculated for no-supported, partly-supported, and completely-supported cases respectively. Meshes with 3 different sizes were examined for a sensitivity analysis. For the verification of the proposed method, a limit equilibrium analysis was conducted and compared with the numerical analysis. The proposed method herein can be used to calculate factor of safety of a tunnel regardless of tunnel shape or geological conditions, and thus can contribute for the improved design and stability assessment of tunnels.

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Equilibrium Moisture Content of Shiitake Mushroom(Lentinus edodes) (표고버섯의 평형함수율에 관한 연구)

  • 최병민;한은정;최주호;홍지형;서재신
    • Food Science and Preservation
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    • v.6 no.1
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    • pp.37-42
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    • 1999
  • The equilibrium moisture content(EMC) of Shiitake mushroom is and important factor because it has a close relationship to storage and drying problems. The determination of the EMC for Shiitake mushroom was made in atmospheres of various constant humidities at four different constant temperatures and the fitting of the five selected EMC models were performed with the experimental EMC data. The desorption equilibrium moisture contents for Shiitake mushroom were increased as the temperature was decreased and the relative humidity was increased. The significant difference of the equilibrium moisture content was appeared between the cap and the stipe of Shiitake mushroom. The Henderson-Thompson model was fitter than the others with the experimental data.

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Slope Failure Surface Using Finite Element Method

  • Ahn, Tae-Bong
    • Journal of the Korean Geotechnical Society
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    • v.15 no.3
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    • pp.27-40
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    • 1999
  • In limit equilibrium methods(LEM), all methods employ the same definition of the safety factor as a ratio of the shear strength of the soil to the shear stress required for equilibrium, employing certain assumptions with regard to equilibrium. In addition, in the conventional finite element method of analysis, the minimum safety factor is obtained assuming certain slip surfaces after the state of stress are found. Although the stress states are obtained from the finite element method(FEM), the slope stability analysis follows the conventional method that assumes a potential slip surface. In this study, a slope stability analysis based on FEM is developed to locate the slip surface by tracking the weakest points in the slope based on the local safety factor considering the magnitude and direction of the shear stresses. It has also been applied to be compared with the slip surfaces predicted by LEM. A computer program has been developed to draw contour lines of the local safety factors automatically. This method is illustrated through a simple hypothetical slope, a natural soil slope, and a dam slope. The developed method matches very well with the conventional LEM methods, with slightly lower global safety factors.

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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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Analysis of Shoreline Response due to Wave Energy Incidence Using Equilibrium Beach Profile Concept (평형해빈단면 개념을 이용하여 파랑 에너지 유입에 따른 해안선 변동 해석)

  • Kim, Tae-Kon;Lee, Jung-Lyul
    • Journal of Ocean Engineering and Technology
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    • v.32 no.2
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    • pp.116-122
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    • 2018
  • Dean's equilibrium beach profile formula was used to investigate the correlation between the static shoreline position and the incident wave energy. The effect of the longshore sediment transport was neglected, and the results showed the reasonable agreement compared with the field observations of Yates et al.(2009), which were conducted for almost 5 years on southern California beaches, USA. The shoreline response varies with the scale factor of Dean's equilibrium beach profile. This implies that the shoreline response could be simply estimated using the sampled grain size without laborious long-term field work. Therefore, the present study results are expected to be practically used for the layout design of submerged or exposed detached breakwaters although the further work is required for performance verification. In addition, after laborous mathematical reviews, the linear relation between incident energy and shoreline response, which was obtained from Yates's field study, yielded a clear mathematical equation showing how the beach slope is related to the grain size.

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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Assessing Bank Competition in Nepal Using Panzar-Rosse Model

  • BUDHATHOKI, Prem Bahadur;RAI, Chandra Kumar;RAI, Arjun
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.11
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    • pp.759-768
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    • 2020
  • The purpose of this study is to assess the state of competition in Nepalese banking over the period from 2010 to 2019. This study employs panel data and a non-structural Panzar-Rosse model to measure the degree of competition in the Nepalese banking industry. The first reduced-form equation is applied to gauge competition, and the second model is used to test the long-run equilibrium in the banking market. The finding reveals that the Nepalese banking market is equilibrium in the long-run. It implies that the factor prices do not affect ROA in the long-run. The result of the H-statistic shows that the Nepalese banking system is operating under the state of perfect competition and is shifted from monopolistic competition to perfect competition. The reduced-form model reveals that the interest income is positive and significantly affected by factor prices. Similarly, the macroeconomic variable GDP growth is positively related to interest income. On the contrary, the bank's specific factors risk and the number of bank branches are inversely associated with the regressand. The outcomes of the study may be advantageous to the policymakers, especially to Nepal Rastra Bank to implement monetary policy and M&A policy for the stability and growth of the financial system of Nepal.

A Competitive Equilibrium Model of the Market for Used Goods (내구재 시장의 경쟁 균형 모형)

  • Kim, Jae-Cheol
    • IE interfaces
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    • v.2 no.2
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    • pp.63-73
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    • 1989
  • The present paper determines the equilibrium price function of used goods and their carry-over age when there are heterogeneous firms with different factor prices. It is shown that the used good market enables more efficient use of durable goods and thereby gains from trades. It is also shown that firms with a lower interest rate and a higher wage rate specialize in using newer goods.

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The Short-term Safety Factor Considering Passive Resistance Effect of Bar Anchor Based on Smart Construction (스마트 건설기반의 강봉앵커 수동저항 효과를 고려한 단기 안전율)

  • Donghyuk Lee;Duhyun Baek
    • Journal of the Korean GEO-environmental Society
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    • v.25 no.4
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    • pp.29-35
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    • 2024
  • This is an analytical study to confirm the passive resistance effect before post-tensioning of steel bar anchors. When using a steel bar as a permanent anchor, if displacement occurs within the slope even before the head load is applied, the displacement is suppressed by the passive resistance caused by the interaction between the steel bar, grout, and surrounding soil. Accordingly, the shape of the failure surface and changes in the safety factor were examined using limit equilibrium analysis and finite element analysis targeting sites where steel bar anchors were actually applied. It was found that the safety factor of the slope reinforced with steel bar anchors is 2.02 using finite element analysis, which is about 5.9% smaller than 2.14 using limit equilibrium analysis. Also, the location of the failure surface was found to be deeper compared to the unreinforced slope. Likewise, the factor of safety has a 153% and 163% increase using finite element method and limit equilibrium analysis, respectively. In addition, the maximum displacement occurs in the lower unreinforced section within the slope, and the displacement is found to be reduced by 42 to 83% at the location where the steel bar anchors are installed.

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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