• Journal of the Korean Geotechnical Society
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• v.26 no.10
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• pp.5-14
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• 2010

The slope stability method using the soil stabilizer is a way to ensure that the slope stability from reinforcing method is environmentally friendly. However, the reinforcing method does not ensure slope stability for lack of research on the reinforcement effect of the mixture with soil. So the application of this method implies difficult technical issues. In this research, reinforcement effect is investigated according to the different ratio of mixture. And the optimum reinforcement depth is proposed according to the height of slope from numerical analysis. The results show that approximately the soil strength increases from two to three times. From numerical analysis, it is possible to estimate the optimum height according to the height of slope. It is anticipated that the use of soil stabilizer will increase the slope stability.

• Journal of Korean Society of Disaster and Security
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• v.12 no.2
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• pp.65-72
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• 2019

More than 64% of Korea's land is occupied by mountain regions, which have terrain characteristics that make it vulnerable to mountain disasters. The trails of Taebaeksan Mountain National Park-the region considered in this study-are located in the vicinity of steep slopes, and therefore, the region is vulnerable to landslides and debris flow during heavy storms. In this study, a slope stability model, which is a deterministic analysis method, was used to examine the potential occurrence of landslides. According to the soil classification of the detailed soil map, the specific weight of soil, effective cohesion, internal friction angle of soil, effective soil depth, and ground slope were used as the parameters of the model, and slope stability was evaluated based on the DEM of a 1 m grid. The results of the slope stability analysis showed that the more hazardous the area was, the closer the ratio of groundwater/effective soil depth is to 1.0. Further, many of the private houses and commercial facilities in the lower part of the national park were shown to be exposed to danger.

• Journal of the Korean Geosynthetics Society
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• v.8 no.1
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• pp.11-18
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• 2009

This paper presents a comparative study of reinforced soil slope by using LEM and SSR-FEM. Current analysis methods for reinforced soil wall are based on LEM. SSR-FEM assumes a reduction of soil strength by a factor to reach a critical state prior to failure based on continuum mechanics. In this study the comparisons are concerned with the factor of safety and the potential failure surface in reinforced soil wall. We investigated the stability of the reinforced soil wall with a slope of $60^{\circ}$ by LEM and SSR-FEM. The comparisons indicated good performance of the SSR-FEM on stability analysis of reinforce soil wall.

• Journal of the Korean Geotechnical Society
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• v.26 no.3
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• pp.47-57
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• 2010

Yield seismic coefficient plays an important role in the estimation of permanent displacement of a soil slope subjected to earthquake using Newmark's sliding block theory. However, yield seismic coefficients currently used in practices are not mechanically rigorous since most of them are estimated using limit equilibrium methods considering equilibrium condition only. Therefore, estimation of permanent displacement of a soil slope based on existing yield seismic coefficient may cause problems. Limit analysis estimating the range of mechanically rigorous solution is thought to be effective in evaluating the validity of existing yield seismic coefficient. In this study, a simple stability chart for yield seismic coefficient useful in practices is proposed by considering various slope conditions including stability number, slope inclination, strength parameters, etc.

• The Journal of Engineering Geology
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• v.31 no.2
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• pp.165-178
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• 2021

The influence of Soil-Water Characteristic Curve (SWCC) fitting parameters for an unsaturated natural slope was evaluated through seepage and slope stability analysis as a function of rainfall. Soil samples were collected from the study area in Jirisan National Park and the physical and mechanical characteristics of unsaturated soil layers were measured in laboratory tests. The saturation depth was calculated via seepage analysis by changing fitting parameters α, the parameter related to the Air Entry Value (AEV) and n, the parameter related to the slope of the SWCC in the range of natural conditions. Slope stability analysis using the limit equilibrium method considered the calculated depth of saturation. Results from seepage analysis for various rainfall conditions indicate the saturation depth in the soil layer suddenly increased as the fitting parameter α decreased; the saturation time for the entire soil layer also decreased. Slope stability analysis considering the calculated depth of saturation shows that the slope safety factor rapidly decreased as the fitting parameter α decreased, whereas the variation in slope safety factor was very small when n increased. Hence, fitting parameter α has a large effect on saturation depth during rainfall and therefore on slope stability, whereas slope stability is relatively unaffected by the fitting parameter n.

• 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.

• The Journal of Engineering Geology
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• v.21 no.1
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• pp.57-64
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• 2011

Three-dimensional slope stability analysis was applied to a failed dual-lithology slope containing both granite and an andesitic dyke, taking account of the differences in shear strength of the different lithologies. A direct shear test of the soil-rock boundary was performed to examine the shear strength of two different types of failure surfaces within different lithologies, and a laboratory test was performed on an upper, weathered soil layer. The test results indicate that shear strength was lower at the soil-rock boundary than within the weathered soil layer. A representative geological section was subjected to two-dimensional slope stability analysis using a limit equilibrium method to assess whether the distribution of lithologies upon the slope influences the results of stability analysis. The results were then compared with those of three-dimensional slope stability analysis, for which input parameters can be varied according to the distribution of lithologies upon the slope. The three-dimensional analysis yielded safety factors of 1.26 under dry conditions and 0.55 under wet conditions, whereas the two-dimensional analysis yielded unstable safety factors of 0.92 and 0.32, respectively. These findings show that the results of stability analysis are affected by the distribution of different lithologies upon the slope. Given that the studied slope collapsed immediately after rainfall, it is likely that the results of the three-dimensional analysis are more reliable.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.720-723
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• 2006

This study performed slope stability analysis by changing analysis methods and shear strength with the slope stability analysis program. The conclusions of the study are as follows. 1) The safe factor of clayey soil applied with Bishop's simple method turned out to be similar to or slightly higher than those of other methods, for both dry and saturated conditions. 2) The safe factor of sandy soil applied with GLE method turned out to be slightly higher than those of other methods. But when applied with Bishop's simple method, it appeared to be slightly higher than those of other methods. 3) The safe factor of ordinary soil applied with GLE method showed the highest result. 4) Janbu method showed the lowest safe factor among all the methods for the above three types of soils.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.529-536
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• 2003

In domestic case occurrence of cut slopes according to construction and expansion of road is necessary more than 70% of country has been consisted of mountain area. In the case of Kang-won Do, there are much mountains locals in road wiping away a disgrace and expanded and slant is connoting collapse danger of incision side by each kind calamity being urgent. When route alteration enforces disadvantageous road extension, stability examination and processing way about large slope happened are serious. During road extension work in the Kang-won DO secure stability for falling rock of road slope and failure that happen and established suitable reinforcement and countermeasure in reply in necessity. The Slope is divided rock slope and soil slope, and then in order to analysis soil slope apply LEM theory. And rock slope examined stability about stereographic projection and wedge failure. Is going to utilize in reinforcement and failure prevention if it is efficient cutting as reinterpreting stability and secure stability and wish to consider effective and robust processing plan of great principle earth and sand side, and present countermeasure inside with these data hereafter applying suitable reinforcement countermeasure about unstable section.

• Tunnel and Underground Space
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• v.25 no.3
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• pp.264-274
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• 2015

In this study, the applicability of geotextile mesh soil nails on slopes was evaluated by numerical analysis to reduce environmental problems which a general soil nailing might produce and to improve its economical efficiency and construction convenience. To this end, in situ pull-out tests were conducted for both general soil nail and geotextile mesh soil nail and their pull-out characteristics were analyzed. Also, finite difference method was used to verify the suitability of numerical simulation. Parameters for nail and ground conditions were selected and sensitivity analysis was performed for the evaluation of slope stability. In addition, analysis was performed by limit equilibrium method which is widely used for slope stability analysis in practice. As a result, if the nail diameter was same, there is no big difference between geotextile mesh soil nails and general soil nails in terms of slope stability. Therefore it can be expected that geotextile mesh soil nails could be effective for slope reinforcement since they could keep a slope as stable as general soil nails and give better economical efficiency and construction convenience than general soil nails.