• Journal of the Korean Geotechnical Society
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• v.16 no.2
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• pp.145-154
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• 2000

오늘날 폐기물 매립장의 구조적 안정성문제는 국내.외적으로 중요한 문제로 대두되고 있으며, 특히, 사면의 차수체계에서의 안정성에 대한 논란이 사회적 문제로 대두되고 있다. 또한, 우리 나라는 주민들의 NIMBY 현상과 국토의 효율적 활용을 위하여, 폐기물 매립장을 해안매립지나 산간지방에 많이 건설하고 있다. 그러나, 이러한 경우 사면구배가 급해지고 토목섬유의 활용이 불가피해져 안정성에 많은 문제점을 내포하게 된다. 이 연구는 폐기물 매립장 사면의 안정성을 해석하기 위하여, 원심모형실험을 실시하였다. 또한, 이론식 및 사면안정 해석 프로그램을 이용하여 안전을 산정하였다. 이 연구에 사용한 토목섬유 점토차수재(GCLs)의 팽윤도는 침출수와 증류수의 투과수에 대하여 22~25%의 팽윤도를 보였으며, 투수계수는 투과수가 침출수일 경우, 1.47$\times$10-10cm/sec, 증류수일 경우, 8.75$\times$10-11cm/sec의 값을 나타내었다. 원심모형실험 결과, 토목섬유 점토차수재의 포화여부와 지오멤브레인(HDPE)의 표면거칠기에 따라 사면 안전율이 각각 변화함을 알 수 있었으며, 표면이 거친 지오멤브레인과 건조한 토목섬유 점토차수재를 사용하였을 때, 파괴가 발생되지 않아 사면안정성이 높은 것으로 평가되었다. 또한, 이론에 의해 도출된 사면의 안전율과 사면안정 해석프로그램에 의한 안전율 계산 시, 전자의 경우가 후자의 경우보다 작게 평가됨을 알 수 있다.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.405-414
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• 2008

When we evaluate slope stability, we regard the slope homogeneous and evaluate slope stability at the most dangerous portion of slope. However, since conditions and properties of rock mass/soil are different from one location to another within a single slope, slope stability evaluated by current concept can not represent slope correctly. This also result in over-reinforcement at the portion where reinforcement is not necessary. In order to solve these problems, we suggest a cell unit evaluation method in which we apply small rectangular cells in a slope and regard each cell as a single slope. In this method, slopes are classified into soil slope and rock slope depending on materials. Strength of rock, volumetric joint count, spacing of joints, condition of joints, ground water condition and so on are examined and SMR and condition index values are calculated. Finally, all data and results are presented as contour maps. We apply the cell unit evaluation method into 3 cut slopes. SMR values estimated by the new method are larger than those by current concept at most portions of slope, indicating that the new method suggested by this research represent slope stability more correctly than methods which were used. This method will prevent over-reinforcement at the portion of slope where reinforcement is not necessary.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.33-41
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• 2003

The large planar failure has occurred in a rock cut slope of highway construction site in Boeun. This area is considered to be unstable since the discontinuity, whose orientation is similar to the orientation of the failure plane, is 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 able to be obtained in limit equilibrium method, DEM 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.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.1 s.12
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• pp.57-64
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• 2004

Recent abnormal weather condition and accompanying increase in forest fire require more study on the effect of forest fire on the stability of mountain slopes. The aims of this paper are to investigate how destroy of trees caused by forest fire influences the stability of mountain slopes and to propose a safety evaluation method for mountain slopes considering the effect of forest fire, in order to minimize the expected damage due to forest fire. To accomplish this aim, the effects of forest fire on the stability of mountain slopes are analyzed in quantitative way, and a slope stability chart is proposed as a result.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.577-587
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• 2007

The length of study area was about 450m, and it was shown the geological condition of distinguished change of rock by cutting slope. In order to establish a slope stability, we carried out an engineering geological investigations about rock constituent, rock structure and a direction of discontinuous plane. The study area was divided into six section considered by direction of cutting slope, height of slope and geological condition. Analysis of cutting slope stability was carried out with stereo-graphic projection method by DIPS program which was feasible of stability analysis with geometrical correlation for a direction of discontinuous plane and direction of cutting slope. From analysis of cutting slope stability considered by construction, stability and economical efficiency, the slope stability countermeasures such as a high tensile wire net, slope protection method and enhanced retaining wall were established and operated which minimized effect caused by lower end of road on a relaxation of huge rock.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.15-15
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• 2002

사면은 인공적 또는 자연적인 현상에 의하여 발생된 경사진 지반을 말하며, 그 안정성은 작용외력과 지반상태 및 지하수 등에 의하여 영향을 받는다. 사면의 파괴는 여러 가지 형태로 일어날 수 있으나 대체로 강성 활동 파괴체가 소성화된 국부적인 지반을 따라서 발생되고, 사면의 파괴형상은 경계조건과 지반상태가 단순할 경우에만 쉽게 예측할 수 있으며, 복잡한 지반상태에서는 많은 노력과 비용을 들여서 정밀하게 조사해야만 어느 정도 실제와 근사하게 예측할 수 있다. 자연 또는 인공사면에서 지질 및 지반상태, 지하수 상태, 사면의 형상, 사면의 규모, 외력의 작용상태 등의 조건을 분석하여 사면파괴를 일으킬 수 있는 원인들을 찾아내어 적합한 안정화대책을 마련하는 방안을 모색한다. 특히 사면을 성토사면, 절토사면, 암절사면, 대절토사면으로 구분하여 사면파괴 원인과 안정화대책에 대해서 심도 있게 검토한다. 사면의 설계 및 안정검토를 위하여 일반적으로 적용하고 있는 사면안정 검토 방법들에 대해서 이론전개 과정에서 발생되는 문제점들과 이들이 결과에 미치는 영향에 대해서 언급한다. 그리고 사면을 안정시키기 위하여 일상적으로 적용하는 대책공법들의 적용성을 사면파괴 원인과 연계해서 판정하는 방안을 검토한다.

• Journal of the Korean GEO-environmental Society
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• v.9 no.5
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• pp.61-69
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• 2008

In general, it has been usually used the method that assess rock slope stability using stereographic projection method, limit equilibrium analysis, numerical analysis and slope stability evaluation table. Several methods for assessing the stability of rock slopes has been proposed on the basis of site investigation data. These method adopted different evaluation items and weighting factors by researchers, organization and nation. But the researches for each evaluation items were insufficient. So the effectiveness of rock slope stability evaluation items for geometrical configuration (slope height, slope direction and angle, dip and dip direction of major discontinuity, absolute value for the direction difference for slope and major discontinuities) and topographical characteristic (possibility of topographical water concentration, upper natural slope angle, slope configuration) using 315 failure and stable highway rock slope analysis data, AV (abnormal value) analysis and NMAV (normalized maximum abnormal value) analysis were evaluated.

• The Journal of Engineering Geology
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• v.20 no.2
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• pp.155-167
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• 2010

In analysis of slope stability, deterministic analysis which yields a factor of safety has been used until recently. However, probability of failure is considered as a more efficient method because it deals with the uncertainty and variability of rock mass. In both methods, a factor of safety or a probability of failure is calculated for a slope although characteristics of rock mass, such as characteristics of joints, weathering degree of rock and so on, are not uniform throughout the slope. In this paper, we divided a model slope into several zones depending on conditions of rock mass and joints, and probabilities of failure in each zone are calculated and compared with that calculated in whole slope. The persistence of joint was also used as a parameter in calculation of probability of failure. A rock slope located in Hongcheon, Gangwondo was selected and the probability of failure using zoning and persistence as parameter was calculated to confirm the applicability of model analysis.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.425-434
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• 2007

In this paper, the stability standards of slopes reclaimed by soils mixed with stone dust were proposed to manage the stone dust as recovery soils. First of all, the mixed ratio between stone dust and natural soil is classified into 5 groups, and a series of soil test was performed in each group. As the results of tests, the shear strength and the maximum dry unit weight were increased in decrease of the mixed ratio of stone dust. On the basis of the investigation to the safety factor standards of embankment slopes in and outside the country, a slope stability rank of slopes reclaimed by mixed soils were divided into 3 stages such as unstable stage, attention stage and stable stage. The slope angle, the slope height and the mixed ratio with stone dust were proposed by the result of stability analysis of slopes reclaimed by mixed soils. As the result of slope stability analysis, the slope angle of 1 : 1.8 at the reclaimed slope should be constructed in case of the slope height of 10 m. Also, the slope angle of 1 : 1.8 and the mixed ratio of stone dust less than 50% should be constructed in case of the slope height of 15 m. The analysis result of reclaimed slope constructed inside the quarry is similar to that of reclaimed slope constructed on the open ground in same conditions of the slope angle, the slope height and the mixed ratio with stone dust. The proposed stability standards of slopes reclaimed by soils mixed with stone dust can be used practically at the quarrying site.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.519-526
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• 2000

강수량 변동에 따른 사면 내의 지하수유동과 사면의 안정성 변화를 동시에 분석.평가하기 위하여 하나의 완전 연동된 수리지질역학적 모델을 제시하였다. 이 모델은 변형성 지질매체 내에서의 지하수유동을 설명하는 일련의 지배식들과 Galerkin 유한요소법에 기초하여 개발되었다. 1990년부터 1999년까지의 서울지역의 건기 (1월) 및 우기 (8월) 강수량 하에 있는 토양 사면에 대해 개발된 모델을 적용하여 일련의 수치실험을 실시하였다. 수치실험의 결과는 강수량이 증가함에 따라 사면의 수리역학적 안정성이 전반적으로 악화됨을 보여준다. 즉 강수량이 증가할수록 공극수압이 증가하고 지하수면이 상승한다. 그 결과 불포화대가 축소되고 삼출면이 팽창되며 사면의 전단부를 따라 지하수유동속도가 증가하게 된다. 동시에 강수량이 증가할수록 사면 전단부를 향해 전반적인 변위량이 증가한다. 그 결과 안전율이 1 이하인 불안전한 지역이 사면 전단부에서 사면 상부 쪽으로 전파.팽창되며 그 두께도 증가한다. 수치실험의 결과는 또한 사면의 표면에서는 전단파괴와 더불어 인장파괴도 발생할 수 있음을 보여준다.