• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.511-518
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• 2000

Characteristics of joint orientation, length, spacing and their distribution are very important factors for slope stability, Especially, the effect of joint spacing is an essential factor of slope stability. This study is to analyze the effect of joint spacing in cases of sliding and toppling, which is a typical failure mode. Joint spacing can divided into vertical spacing(spacing) and horizontal spacing(gap). And then, the spacing/length ratio of joint directly affect rock slope failure. When the ratio is below 0.05, the possibility of failure is rapidly increased. In case of toppling, the possibility of failure depends on the ratio of spacing to height of slope ratio slope. As the ratio decreases, the possibility of toppling failure increased. The critical ratio of spacing to height of slope is determined by the dip angle of the slope and the orientation of joint sets.

• 한국산림과학회지
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• 제89권1호
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• pp.33-40
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• 2000

본 연구는 변성암지역의 임도를 대상으로 비선형모델인 퍼지이론을 이용하여 임도 성토사면 붕괴가능성을 평가하였다. 그 결과는 다음과 같다. 요인별 붕괴위험도는 총노폭이 4~5m, 종단물매 $2^{\circ}$ 이하, 성토사면길이 8m이상, 성토사면경사 $40^{\circ}$ 이상, 노선위치는 능선부, 토질은 풍화암, 산지경사 $40^{\circ}$ 이상, 사면방위는 북서사면, 사면종단변형은 철(凸)형사면에서 가장 크게 나타났으며, 붕괴요인의 중요도는 성토사면길이>성토사면경사>임도위치>토질>사면방위>사면종단면형 순으로 나타났다. 퍼지이론에 의한 임도 성토사면의 붕괴가능성은 퍼지적분값이 0.485이하에서 안정, 0.620이상은 붕괴가능성이 큰 것으로 평가되었으며, 판별적중률은 74.6%로 나타났다. 또한 요인의 수준을 6개로 축소하여 붕괴가능성을 평가한 결과, 퍼지적분값이 0.441이하는 안정, 0.583이상은 붕괴가능성이 큰 것으로 나타났고, 판별적중률은 78.0%로 다소 향상되었다.

• 한국농공학회지
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• 제39권1호
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• pp.112-121
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• 1997

The aim of this study was to analyze the slope stability relating to the failure of cut slopes and the characteristics of stress-strain relations obtained by limit equilibrium method, finite element method, and stereographic projection method for the reinforced cut slopes. The following conclusions were made : 1.To use stereographic projection method led to little possibility to take the toppling and wedge failure while to use the other methods led to the failure. It was recommended to reduce the slope inclination from 1:1 to 1: 1.5~1 :1.8 and adopt coir mesh method to protect the slope surface. position with the horizontal displacement after final excavation moved to the excavation base. The maximum shear strain values concentrated at the excavation base indicated the possibility to induce the local failure. 3. It was recommended that the slope inclination for blast rock with the slope height larger than l0m was 1: 0.5, 1:1, and 1: 1~1 :1.5 for hard rocks, soft and ordinary rocks, and ripping and soils, respectively. 4. Berm width criteria for blast rock with the slope height larger than l0m were recommended as follow : 2~3m per 20m slope height for hard rocks, 1 ~2m per l0m slope height for soft and ordinary rocks, 1 ~ l.5m per 5m slope height for ripping and soils.

• 한국지반환경공학회 논문집
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• 제17권5호
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• pp.5-16
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• 2016

A rainfall induced slope failure is a common natural hazard in mountainous areas worldwide. Sudden and rapid failures which have a high possibility of occurrence in a steep slope are always the most dangerous due to their suddenness and high velocities. Based on a series of experiments this study aimed to determine a critical angle which could be considered as an approximate threshold for a sudden failure. The experiments were performed using 0.42 mm mean grain size sand in a 200 cm long, 60 cm wide and 50 cm deep rectangular flume. A numerical model was created by integrating a 2D seepage flow model and a 2D slope stability analysis model to predict the failure surface and the time of occurrence. The results showed that, the failure mode for the entire material will be sudden for slopes greater than $67^{\circ}$; in contrast the failure mode becomes retrogressive. There is no clear link between the degree of saturation and the mode of failure. The simulation results in considering matric suction showed good matching with the results obtained from experiment. A subsequent discarding of the matric suction effect in calculating safety factors will result in a deeper predicted failure surface and an incorrect predicted time of occurrence.

• 지질공학
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• 제17권2호
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• pp.289-297
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• 2007

매년 강우로 인해 발생되는 사면파괴는 많은 재산피해와 인명피해를 발생시키고 있다. 사면재해로부터의 피해저감을 위해 인간의 생활권과 인접한 사면에 대한 지속적인 관리를 통해 이들의 안정성 검토와 보강 대책이 요구된다. 연구지역은 편마암으로 이루어진 암반사면으로써 단층작용으로 인해 대규모 절리군이 형성되어 있는 풍화암 내지 연암의 풍화 특성을 보여준다. 조사사면을 자연사면과 절취사면으로 구분하여 현장자료를 검토한 결과, 자연사면에서는 주 절리군이 형성된 4개 지점에서 평면파괴와 쐐기파괴 가능성이 우세하였으며, 절취사면의 경우 8개 지점에서 쐐기파괴 발생 가능성이 높게 나타났다. 또한 SLIDE 2D에 적용해 이들 사면의 최소안전율에 대한 수치해석 결과에서는 자연사면보다 절취사면의 안정성이 비교적 취약한 것으로 분석되었다.

• 한국산림과학회지
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• 제90권3호
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• pp.324-330
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• 2001

본 연구는 비선형모델인 퍼지이론을 이용하여 화성암 지역의 임도성토사면을 대상으로 붕괴가능성 예측모델을 개발하였다. 그 결과는 다음과 같다. 임도 성토사면 붕괴요인의 중요도는 성토사면길이, 성토사면경사, 사면구성물질, 사면방위, 노선위치 등의 순으로 나타났으며, 붕괴위험도는 성토사면길이 8m 이상, 성토사면경사 $40^{\circ}$ 이상, 풍화암 사면, 북동사면 및 능선부 사면에서 크게 나타났다. 임도 성토사면의 붕괴예측 모델은 퍼지적분값 0.5를 기준으로 할 때, 최적화 계수(c)가 0.15, ${\lambda}$값이 3.1165인 경우에 최적 모델로 산출되었으며, 이때의 판별적중률은 86.8%로 모델의 적합성이 매우 높은 것으로 나타났다.

• 터널과지하공간
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• 제5권4호
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• pp.308-317
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• 1995

The stability study on the rock slope where have produced failures in Boryung dam site was evaluated using the streonet analysis techniques. SMR(Slope Mass Rating) approach which is suitable for preliminary assessment of slope stability in rock was also carried out for rating rock mass. The 3-4 major discontinuity sets are distributed and all type of failure(plane, wedge and toppling failure) are presented in this slope face. The dip of slope must be lowered to friction angle(26degree), otherwise the possibility of plane and toppling faiue will always exist in this slope.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.1171-1182
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• 2009

The purpose of this case study is stability security in Talus and Coal Shale. The failure possibility of Talus area is high because of ground loss. The Coal Shale area is very week and large scale sliding possibility is high.

• Geomechanics and Engineering
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• 제2권2호
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• pp.125-140
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• 2010

Slope stability analysis of the right abutment of a railway bridge proposed at about 350 m above the ground level, crossing a river and connecting two huge hillocks in the Himalayas, India is presented in this paper. The site is located in a highly active seismic zone. The rock slopes are intensely jointed and the joint spacing and orientation are varying at different locations. Static slope stability of the rock slope is studied using equivalent continuum approach through the most commonly used commercial numerical tools like FLAC and SLOPE/W of GEOSTUDIO. The factor of safety for the slope under static conditions was 1.88 and it was reduced by 46% with the application of earthquake loads in pseudo-static analysis. The results obtained from the slope stability analyses confirmed the global stability of the slope. However, it is very likely that there could be possibility of wedge failures at some of the pier locations. This paper also presents the results from kinematics of right abutment slope for the wedge failure analysis based on stereographic projections. Based on the kinematics, it is recommended to flatten the slope from 50o to 43o to avoid wedge failures at all pier locations.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.736-744
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• 2009

The abrupt failure of slope caused by a concentrated rainfall would be a disaster in this country. Specially, the soil slope may be collapsed by the rainfall seepage, however, there is not much information for the mechanism of slope failure during rainfall. As analyzing the stability of slope by rainfall, the conventional method is to put the ground-water level on the surface of slope. However, it may provide the over-reinforcement for the slope stability. Futhermore, although over-reinforcement for the slope was fulfilled, the possibility of potential slope failure still exists. In this study, the slope stability by the conventional design method and the causes of unstable slope during rainfall were investigated. To analyze the slope stability by rainfall, the computer program SEEP/W for the analysis of seepage was used. As changing the intensity and duration of rainfall in SEEP/W, the analysis were performed. After completion of analysis, the porewater pressure data from SEEP/W was applied to SLOPE/W. As a results of this analysis, it is not reasonable that the groundwater level is going up to the surface of slope during rainfall. Therefore, the conventional reinforcement for the slope stability is not obvious to satisfy the criterion safety factor during rainfall. The reasonable counterplan is to install drainage hole on the surface of slope in order to prevent erosion and debris flow.