• 건설안전기술
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• 통권47호
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• pp.56-62
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• 2008

In order to apply the Limit Equilibrium Method generally used for the slope stability analysis to the vertical excavation walls reinforced by soil-nailing, in this study, the Limit Equilibrium Method for the temporary shoring facilities reinforced by soil-nailing was proposed, which is based on the stability for the horizontal displacement. In this study, the relation of the internal friction angles of the ground and the vertical excavation depths was arranged, which is satisfying the stability on the horizontal displacement by using the verification of the Limit Equilibrium Method. And then, the rational reinforcing length of soil-nailing was proposed for the critical areas. In addition, the modified safety ratio satisfying the stability on the horizontal displacement was proposed, when the Limit Equilibrium Method was applied to the vertical excavation walls reinforced by soil-nailing.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.643-650
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• 2002

The large planar failure has occurred in a rock cut slope of highway construction site in Boeun. This area is considered as unstable since the discontinuities whose orientations are similar to the orientation of the failure plane, are observed in many areas. Therefore, several analysis techniques such as SMR, stereographic analysis, limit equilibrium, numerical analysis, which are commonly used in rock slope stability analysis, are adopted in this area. In order to analyze the stress redistribution and nonlinear displacement caused by cut, which are not obtained in limit equilibrium method, the UDEC and shear strength reduction technique were used in this study Then the factors of safety evaluated by shear strength reduction technique and limit equilibrium were compared. In addition, the factor of safety under fully saturated slope condition was calculated and subsequently, the effect of the reinforcement was evaluated.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.534-537
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• 2007

The soil nailing was generally using method in practical business, in application of the soil nailing, the analysis was primarily used to Beam-Colum Method, Finite Element Method and Limit Equilibrium Method. Beam-Colum Method and Finite Element Method were able to examine transformation but widely using Limit Equilibrium Method wasn't able to examine transformation and displacement Therefore, this study was focused on presenting stability in comparison with former study-results about horizontal displacement of the soil nailing retaining-walls satisfing a criterion safety factor of Limit Equilibrium. There were performing comparison field measurements and former study-results in first step.

• 한국환경과학회지
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• 제4권1호
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• pp.91-103
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• 1995

The reaction rate, equilibrium, and flow injection analysis methods were fundamentally evaluated for the determination of aqueous ammonia. The selected indophenol blue method was based on the formation of indophenol blue in which ammonium ion reacted with hypochlorite and phenol in alkaline solution. In the optimized reaction condition, the reaction followed 1st order reaction kinetics and the final product was stable. The absorbance measurements before and after the equilibrium were utilized for the reaction rate and equilibrium methods. The reaction rate methods, based on the relative analytical signals for the possibility of eliminating interferents, were shown to have good linear calibration curves but the detection limit and the calibration sensitivity were poorer than those in the equilibrium method. The detection limits were 32-49 pub and 24 pub for the reaction rate and equilibrium methods, respectively In the flow injection analysis, the absorbance was measured before the equilibrium reached and thus resulted in 30% reduction of calibration sensitivity. However, the detection limit was 11 ppb, indicating that the peak-to-peak noise for the blank was remarkably improved. Compared to the manual methods, the optimized experimental condition in a closed reaction system reduced the blank absorbance and the inclusion of ammonia from the atmosphere was prevented. In addition, highly reproducible mixing of sample and reagents and analytical data extracted from continuous recording showed excellent reproducibility.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.1113-1124
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• 2009

The limit equilibrium method and finite element method have been commonly used to assess the stability of anchored slope. However, the existing limit equilibrium methods do not consider the load transfer of anchor and, if the potential failure surface crosses the bonded zone of anchors, the anchor loads are not included in computing the factor of safety. In this paper, simplified bishop method, one among several methods based on the limit equilibrium is used to develope the Excel Sheet program and the working load of anchor along the failure surface is calculated by Flamant's formula, proposed by Morlier and Tenier(1982). Additionally, the finite element analysis of anchored slope considering the load transfer is performed in order to compare with the result from the limit equilibrium analysis and analyze the reinforced effect of anchor. From this study, new modelling method that limits the reinforcing range and considers the load transfer is proposed and Excel Sheet program is developed. The factor of safety for several cases between PC STABL and Excel Sheet program is also compared for verification of the program.

• 한국지반공학회논문집
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• 제19권4호
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• pp.33-41
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• 2003

연구대상 사면은 충북 보은군 보은읍 도로공사구간 내의 절취사면으로 절취시공 후 암반사면내의 일부 구간에서 평면파괴로 인한 사면 붕괴가 발생하였다. 이 구간에서는 파괴면과 유사한 방향성을 갖는 불연속면이 암반사면 내에 다수 분포하여 추가 붕괴가 예상되는 불안정한 상태이다. 따라서, 본 사면에 대하여 암반사면의 안정성 해석에 보편적으로 사용되는 SMR, 평사투영법, 한계평형법 및 수치해석 등의 기법을 이용하여 사면의 안정성을 해석하였다. 사면의 안정성평가에 보편적으로 사용되는 한계평형법은 간단한 계산에 의해 사면의 안정성을 평가할 수 있는 장점이 있으나 파괴 활동면을 가정할 수 없는 단일 안전율에 의해 전체 사면의 안정성을 평가하는 단점이 있다. 따라서, 본 연구에서는 개별절리를 고려하여 사면의 안정성을 평가하는 전단강도 감소기법으로부터 안전율을 계산하였으며, 이를 한계평형해석의 결과와 비교ㆍ분석하였다. 또한 본 사면내에 지하수 영향을 고려하고 보강공법을 적용하여 종합적인 안정성을 검토하였다.

• Geomechanics and Engineering
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• 제24권4호
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• pp.399-406
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• 2021

It is a key issue in the tunnel design to evaluate the stability of the excavation face. Two efficient analytical models in the context of the limit equilibrium method (LEM) and the limit analysis method (LAM) are used to carry out the deterministic calculations of the safety factor. The safety factor obtained by these two models agrees well with that provided by the numerical modelling by FLAC 3D, but consuming less time. A simple probabilistic approach based on the Mote-Carlo Simulation technique which can quickly calculate the probability distribution of the safety factor was used to perform the probabilistic analysis on the tunnel face stability. Both the cumulative probabilistic distribution and the probability density function in terms of the safety factor were obtained. The obtained results show the effectiveness of this probabilistic approach in the tunnel design.

• Structural Engineering and Mechanics
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• 제41권3호
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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.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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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.

• 한국지반공학회논문집
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• 제15권5호
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• pp.19-28
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• 1999

본 논문에서는 사면붕괴해석에 대한 유한요소법의 적용에 대하여 검토하였다. 사면안정문제에 대해 가장 일반적으로 사용되는 방법은 한계평형이론에 의한 절편법이다. 또한 유한요소법은 지반의 응력, 변형률을 분석하는 방법으로 널리 인식되어 있다. 본 논문에서는 유한요소법으로 사면안정해석시, 요구되는 최소안전율 계산방법을 효율적으로 고려하는 방법에 대하여 검토하였다. 그리고 유한요소법으로 사면의 붕괴해석을 하는 경우에, 적용되는 해석방법 및 그 결과에 미치는 요인에 대하여 검토하였다. 또한, 여러 사면의 경우에 대하여 기존의 한계평형법에 의한 절편법과 유한요소 해석결과를 비교, 검토하였다.