• The Journal of Engineering Geology
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• v.27 no.3
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• pp.267-274
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• 2017

Behavior of rock mass depend on the mechanical properties of intact rock and geometrical property of discontinuity distributed in rock mass. In case of rock slope, particularly, location of slope failure surface and behavior after failure are changed due to discontinuities. In this study, two 3D slope stability analysis methods were developed for two different failure types which are circular failure and planar failure, considering that failure type of rock slope is dependent on scale of discontinuity which was then applied to real rock slope to review the applicability. In case of circular failure, stable condition was maintained in natural dry condition, which however became unstable when the moisture content of the surface was increased by rainfall. In case of planar failure, rock slope become more unstable comparing to dry condition which is attributable to decrease in friction angle of discontinuity surface due to rainfall. Viewing analysis result above, analysis method proved to have well incorporated the phenomenon occurred on real slope from the analysis result, demonstrating its applicability to reviewing the slope stability as well as to maintaining the slope.

• Structural Engineering and Mechanics
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• v.89 no.3
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• pp.253-263
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• 2024

Slope stability is generally paid more attention to in slope protection works, especially for slope containing weak layers. Two indexes of safety factor and failure model are selected to perform slope stability. Moreover, the finite element limit analysis method comprehensively combines the advantage of the limit analysis method and the finite element method obtaining the upper and lower bounds of the safety factor and the failure mode under the slope stability limit state. In this study, taking a waste dump containing a weak layer as an engineering background, the finite element limit analysis method is adopted to explore the potential failure mode. Meanwhile, the sensitivity analysis of slope stability is performed on geometrical and geotechnical parameters of the waste dump. The results show that the failure mode of the waste dump slope is two wedges if the weak layer is located on the ground surface (Model A), while the slope can be observed as three wedges failure if the weak layer is below the ground surface (Model B). In addition, both failure modes are highly sensitive to the friction angle of the weak layer and the shear strength of waste disposal, and moderately sensitive to the heap height, the dip angle and cohesion of the weak layer, while the toe cutting has limited effect on the slope stability. Moreover, the sensitivity to the excavation of the ground depends on the location of the weak layer and failure mode.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1351-1358
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• 2008

This paper presents how the load transfer mechanism of the ground anchor affects on the stability analysis of anchored slope. The finite element analysis and the conventional limit equilibrium analysis on the anchored slope were performed and compared. The limit equilibrium analysis of the anchored slope is quite open used in design practice due to the easiness of the analysis. However, the load transfer mechanism is not considered properly for the analysis. When the failure surface passes through the bonded length of an anchor, the anchor load is disregarded and the factor of safety for the anchored slope is smaller than it should be. In this study, the load transfer distribution was incorporated into the limit equilibrium stability analysis of the anchored slope and the results were compared with the results of finite element analysis.

• Economic and Environmental Geology
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• v.36 no.4
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• pp.313-320
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• 2003

Slope disaster is one of the repeated occurring geological disasters in rainy season resulting in about 23 human losses in Korea every year. The slope disaster, however, mainly depends on the spatial and climate properties. such as geology, geomorphology, and heavy rainfall, and, hence, the prediction or hazard analysis of the slope disaster is a difficult task. Therefore, GIS and various statistical methods are implemented for slope disaster analysis. In particular, GIS technique is widely used for the analysis because it effectively handles large amount of spatial data. The GIS technique. however, only considers the statistics between slope disaster occurrence and related factors, not the mechanism. Accordingly. an infinite slope model that mechanically considers the balance of forces applied to the slope is suggested here with GIS for slope disaster analysis. According to the research results, the infinite slope model has a possibility that can be utilized for landslide prediction and hazard evaluation since 87.5％ of landslide occurrence areas have been predicted by this technique.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.58-70
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• 1989

The paper compared the Bishop methed to the Fellenius method in the analysis of slope stability. Laboratory model test was carried out in the case of seepage flow considered. The results obtained from this study were summarized as follows; 1. The slice pieces of 10 were enough to analysis the slope stability. 2. The safety factor. by the Fellenius method was lower than the Bishop method by the 96 to 97% in the case of no seepage flow and by the 95 to 96% in the case of seepage flow considered. 3. Besides the parameter of soil and slope, the safety factor of slope was influenced by the height of slope. This phenomena was distinct in the height of height less than 10 meters. 4. In the case of clay, there was no difference in the safety factor of slope between Fellenius and Bishop rnethod. The safety factors of slope with the seepage flow considered were lower than those with no see-page flow. 5. The influence of cohesion on the safety factor was more significant in the Bishop method than in the Fellenius method. 6. The slope failure of model test of A and B soil samples with high permeability coefficient was taken place slightly in vicinity of toe by the concentration of stress and gradually increased 7. Under condition of same slope height, the shapper the slope, the shorter the radius and the center of critical circle appered downward and finally failure of slope occured inside the slope.

• The Journal of Engineering Geology
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• v.27 no.1
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• pp.21-29
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• 2017

Variations in matric suction were compared between field measurements and numerical analysis for a tailings dump slope. We performed an analysis of slope stability using precipitation records measured in the field, selecting the period (72 hours) of highest rainfall intensity during the field monitoring, for which the matric suction and rainfall records measured in the field were analyzed. In addition, we applied the precipitation records of this period to the numerical analysis. SEEP/W and SLOPE/W were used to analyze the seepage flow in the slope due to rainfall and to investigate the slope stability considering the wetting front depth from the ground surface, respectively. The seepage analysis, using SEEP/W, was carried out on the rainfall data obtained in the field. Comparisons between the field monitoring data and simulation results for matric suction show some quantitative difference but similar patterns of temporal variation. According to the results of slope stability analysis using SLOPE/W and the results of seepage analysis, the safety factor of the slope showed a sudden increase at the point of rapid increase in rainfall intensity. It then recovered because subsequent rainfall was scarce. Therefore, the stability of the tailings dump slope can be reasonably estimated if seepage and slope stability analyses, based on precipitation records, have been carried out.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.681-686
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• 2006

This study is to examine slope activity safety ratio on the strength of the natural sample or soil collected through field test in the slope activity region during destruction happened in the course of soil-relocating work planned for ground improvement under strict supervision at the house-building site, using Bishop's slope analysis method and investigate relationship between slope analysis theories and actual destruction so as to compare determining method of clean water of soil essential for slope activity analysis and accuracy of resulting value of clean water of soil.

• Land and Housing Review
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• v.9 no.2
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• pp.51-57
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• 2018

The causes of landslides are dependant on rainfall events and the soil characteristics of a slope. For the conventional slope stability, the slope stability analysis has been carried out assuming the saturated soil theory. But, in order to clearly explain a proper soil slope condition by rainfall, the research should be performed using the unsaturated soil mechanism suitable for a soil slope in the field. In the study, by using two major categories of soils in Korea, such as granite and gneiss weathered soils, landslide model test and finite element method have been compared with the difference of seepage and soil stability analysis. The hydraulic conductivity of gneiss weathered soil is slower than that of granite weathered soil, and the gneiss weathered soil contains much finer soils than the granite weathered soil. It was confirmed that the instability of the slope was progressing slowly due to the slow rate of volumetric water content of the surface layer.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.06a
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• pp.111-124
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• 1998

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.620-625
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• 2009

The seismic slope stability is most often evaluated by the pseudo-static limit analysis, in which the earthquake loading is simplified as static inertial loads acting in horizontal and/or vertical directions. The transient loading is represented by constant acceleration via the pseudostatic coefficients. The result of a pseudostatic analysis is governed by the selection of the value of the pseudostatic coefficient. However, selection of the value is very difficult and often done in an ad hoc manner without a sound physical reasoning. In addition, the maximum acceleration is commonly estimated from the design guideline, which cannot accurately estimate the dynamic response of a slope. There is a need to perform a 2D dynamic analysis to properly define the dynamic response characteristics. This paper develops the modified one-dimensional seismic site response analysis. The modified site response analysis adjusts the density of the layers to simulate the change in mass and weight of the layers of the slope with depth. Multiple analyses are performed at various locations within the slope to estimate the change in seismic response of the slope. The calculated peak acceleration profiles with depth from the developed procedure are compared to those by the two-dimensional analyses. Comparisons show that the two methods result in remarkable match.