• Geotechnical Engineering
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• v.14 no.3
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• pp.123-134
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• 1998

To analyse the stability of a slope composed of waste material produced in a closed lead mine, numerical modeling has been carried out in two dimension using FLAC, finite difference program. The research was focused on the effect of the earthquake as well as a rise of water table upon slope stability. The numerical results have shown that the slope would not be safe against earthquake event and that the increase of pore pressure due to a rise of water table up to the ground level may result in a failure of the slope. On the basis of numerical analyses and site investigation, two sorts of measures have been taken. In short term, removal of a part of materials deposited on the top of the pile is required to increase immediately safety factor of the slope even a little. In ling term, it is necessary to repair drainage facilities and dam which covers waste material so that the slope is prevented from failure in a radical manner. It has been confirmed by numerical analyses that an improvenment of the stability can be in a great extent expected after such measures have been performed.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.4
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• pp.43-51
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• 2003

The purpose of this study was evaluate to the stability on cut slope of forest roads by forest environmental factors. The total of 19 environmental factors on cut slope of forest roads were investigated in about 42.74km constructed during 1987 to 1993 in Gyeongnam and Jeonnam province. The evaluation of slope stability in forest roads were conducted by the discriment analysis. The main factors influencing the stability of cut slope were significant in order of coverage, soil hardness, degree of slope, altitude, silt loam, convex(凸) and compound(凹凸). The centroids value of discriminant function in the stability and unstability area estimated to -1.194 and 1.127, respectively. The boundary value between two groups related to slope stability was -0.072. The prediction rate of discriminant function for stability evaluation of was as high as 90.4%.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.569-583
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• 2018

The purpose of this study is to identify the collapse characteristics by analyzing various factors causing collapse based on field survey and existing data on rock slopes occurring in the construction of roads and industrial complexes in Gyeongsangnam - do area. In the case of the slope where the slope has been directly surveyed, the analysis of the collapse characteristics can be used for the prediction and prevention of slope failure through the continuous collection of the slope data, database construction, management and analysis. The evaluation items used in the collapse characteristics of slope were selected among the items that can be regarded as objective evaluation items among the overlapping factors by comparing the evaluation items frequently used for the evaluation of the existing slope stability among various factors. The type of destruction of the rock slope depends on the type of carcass of the bedrock, such as planar fracture, wedge fracture, onho fracture, and conduction fracture, which are different from each other. And the slope stability analysis should be performed accordingly.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.3
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• pp.1-19
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• 2014

This study aims to assess the slope stability variation of Jeonbuk drainage areas by RCM model outputs based on A1B climate change scenario and infinite slope stability model based on the previous research by Choi et al.(2013). For a large-scale slope stability analysis, we developed a GIS-based database regarding topographic, geologic and forestry parameters and also calculated daily maximum rainfall for the study period(1971~2100). Then, we assess slope stability variation of the 20 sub-catchments of Jeonbuk under the climate change scenario. The results show that the areal-average value of safety factor was estimated at 1.36(moderately stable) in spite of annual rainfall increase in the future. In addition, 7 sub-catchments became worse and 5 sub-catchments became better than the present period(1971~2000) in terms of safety factor in the future.

• Economic and Environmental Geology
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• v.47 no.2
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• pp.121-131
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• 2014

The stability of rock slope is mainly controlled by the orientation and shear strength of discontinuties in rock mass. Therefore, in kinematic analysis, the orientation of the combination of discontinuities and slope face is examined to determine if certain modes of failure can be occurred. In previous kinematic analysis, a representative orientation of the slope face and mean orientation of discontinuity set were used as input parameters. However, since the orientations of slope face varies according to locations of measurement, the representative slope face orientation could cause misunderstanding for kinematic instability. In addition, since the orientations of each discontinuity are scattered in the same discontinuity set, there is the possibility that uncertainties are involved in the procedure of kinematic analysis. Therefore, in this study, the detailed digital topographic map was used to obtain the orientation of slope face. In addition, the probabilistic analysis approach was utilized to deal properly with the uncertainties in discontinuity orientation. The proposed approach was applied to steep slopes in mountain road located in Baehuryeong, Chunncheon city, Gangwon-Do. The analysis results obtained from the deterministic and probabilistic analysis were compared to check the feasibility of proposed the analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.512-515
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• 2012

최근의 재해 발생은 하천에 의한 범람, 제방의 붕괴 등에 의한 피해발생보다는 일정지역에 국한적으로 내수배제 불량, 토사유출, 산사태 등으로 인한 피해의 발생이 증가하고 있다. 특히나 도시지역과 신규개발지역을 중심으로 집중호우로 인한 토사유출 등으로 인한 배수로 막힘, 산사태등의 2차적인 피해가 증가하고 있는 추세이다. 2011년의 서울의 우면산 산사태 등과 같은 도시중심에서의 피해와 강원도 등의 신규개발지역에서의 토사로 인해 2차, 3차 피해는 국지적이고 예측이 불가능한 곳에서 발생되고 있다. 이러한 토사유출, 산사태에 의한 예측기법은 최근의 정보기술의 발달로 인해 보다 다양한 방법의 접근들이 시도되고 있으며, 이에 대한 정량적인 평가기법들이 개발되고 적용되고 있다. 본 연구에서는 산지지형의 소규모 개발지의 토사재해의 위험성을 평가하기 위하여 GIS 기술을 이용한 사면의 안정성과 산사태 위험성을 평가하는 대표적인 방법으로 Pack et al. (1998)이 제안한 수리적 무한사면 안정모델과 결합하여 사면안정분석을 위해 개발된 SINMAP을 이용하여 소규모 개발지역의 토석류 해석과 사면의 안정성 검토 그리고 범용토양공식을 이용하여 토사유출량을 산정하여 개발지역내 사면 및 토사재해의 위험성을 평가하였다. GIS를 이용한 지형적 특성에 따른 사면의 위험성과 토사유출량 해석 결과를 이용하여 소규모 개발지역의 토사재해의 위험성을 정량적이고 다각적으로 평가하여 재해발생에 따른 위험성을 노출하고 이에 대한 대책 수립에 도움이 될 것으로 판단된다.

• Economic and Environmental Geology
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• v.42 no.4
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• pp.357-366
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• 2009

Since weathering weakens the rock fabric and exaggerates any structural weakness, it affects mechanical properties as well as physical and chemical properties of rock. Weathering leads to a decrease in density, strength, friction angle and cohesion, and subsequently it affects negatively on the stability of rock slope. The purpose of the study is to investigate the changes of the rock slope stability caused by discontinuities which have different weathering grades. For that, the discontinuity samples which are divided into two different weathering grades are obtained from the field and tested their mechanical properties such as JCS, JRC and residual friction angle. In order to evaluate the effects on the stability of slope due to weathering, the deterministic analysis is carried out. That is, the factors of safety for planar failure are calculated for rock masses which have two different weathering grades, such as fresh and weathered rock mass. However, since the JRC and friction angle values are widely scattered and the deterministic analysis cannot consider the variation, the factors of safety cannot represent properly the stability of the rock slope. Therefore, the probabilistic analysis has been used to consider the scattered values. In the deterministic analysis, the factors of safety for the fresh discontinuity and weathered discontinuity are 1.25 and 1.0, respectively. The results indicate the fresh discontinuities are stable for planar failure and the weathered discontinuities are marginally stable. However, the probabilities of failure for the fresh discontinuity and weathered discontinuity are 25.6% and 45.9%, respectively. This shows that both discontinuities are analyzed as unstable in the probabilistic analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1349-1357
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• 2010

절토사면의 안정성은 1차적으로 사면 자체의 지반 구조에 의해서 결정되지만 2차적으로 강우와 강설에 의한 수리적인 요소의 영향을 받는다. 매 년 여름 집중호우 기간에 많은 사면들이 붕괴되는 사례를 볼 때, 수리적인 요소가 사면의 안정성에 큰 영향을 주는 것을 알 수 있다. 수리제어공법의 목적은 물이 배수될 수 있는 길을 만들어주는 것으로 그 목적은 매우 간단하다. 하지만 공법이 시공된 이후 강우와 강설로 인해 유입되는 토사, 낙엽이 관리 소홀로 도수로나 배수로를 막아 본래의 역할을 하지 못하는 경우가 대부분이다. 본 연구에서는 이와 같은 문제점으로 발생한 국내 사례를 통해 사면에 적용되는 수리제어공법들의 유지관리 개선방안에 대해 논의하고자 한다.

• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.385-392
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• 2018

The slope stabilization analysis was performed by conducting survey and selecting the representative section in order to improve slope composition and management technology of masonry embankments in the quarry area, The mean slope of the masonry retain wall (A, B, C, D, E, F) was $38.5^{\circ}$, although the steep slope of the lowest slope (A) as $59^{\circ}$. The horizontal distance of the masonry embankments is 66.2 m and the slope height is 48.3 m. However, the inclination of the masonry embankments is relatively steep and visually unstable. The slope stability analysis for the slope stability analysis was taken into account during the drying and saturation. The slope stability analysis during saturation was performed by modeling the fully saturated slope. The strength constants of the ground were divided into two groups. The safety factor for dry period was 1.850 and the safety factor for rainy season was 1.333. The safety rate of dry period and rainy season was above 1.5 and 1.2. However, the weathered granite on the upper part of the masonry embankments at the time of heavy rainfall is considered to have a high risk of slope erosion and collapse. Therefore, it is considered necessary to take measures for stabilization through appropriate maintenance such as drainage installation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.45-53
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• 2018

Among the various slope stabilization methods, the green soil method based on the growth of plants is advantageous to the environment, but the durability and slope stability are insufficient when the green soil method is applied to a steep slope and rock slope sites. Therefore, in this study, green soil, which improved the adhesion performance and the vegetation environment, was developed using cementitious materials and ECG, and the durability and slope stability as well as the possibility of its use as a rock vegetation base material were assessed. From the results, the adhesive force and internal friction angle were higher than that of the existing green soil so that it could be used for in situ construction. The soil hardness value was 26 mm, which was slightly higher than that of the best growth condition of the plant, 18~23 mm, and the drying shrinkage strain was approximately 3%; hence, it is not expected to affect the durability of green soil. The results of a rainfall intensity simulation for evaluating the slope adhesion force showed that slope failure did not occur under all conditions. The damage decreased with increasing slope angle. Therefore, the green soils developed in this study have excellent durability and slope stability and can be used for rock slope sites.