• The Journal of Engineering Geology
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• v.25 no.2
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• pp.189-199
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• 2015

Our country's leading granite weathered soil of the ground slope failures that occur in cutting slope most cases, it does not require in-depth to the shear strength most of the surface layer is affected by weathering (1~2 m) at a shallow depth close to the ground, it is important to identify the reliability. Based on the result obtained in actual field investigation, the field slope type was classified by each type of wedge slope, Infinite slope, finite slope -I and finite slope -II, and the slope stability was examined respectively. In addition, using the numerical analysis results, the relationship between the slope inclination angle and safety factor was analyzed and it tried to offer basic data to which the stability in the field slope was able to be estimated by analyzing the safety factor change of the slope according to the slope type. In this study, classified into four types of natural slope, safety factor estimation method by slope types is proposed through the numerical analysis. However, some limit exists in generalizing in this research because it does not test various case studies. Therefore, the case study of a wide range of various sypes to assess the safety of various types slope can be made, accommodate a wide range of field conditions reasonable risk evaluation criteria may be derived.

• Journal of the Korean Geotechnical Society
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• v.30 no.10
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• pp.45-54
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• 2014

Many studies have been made on investigation, design, explanation and treatments etc. to minimize slope failure. However, the problem is that failures of cutting slope and natural slope due to Typhoon and localized heavy rainfall are still not reduced. It is difficult to treat the problem by only strengthening the design standard. And it is very necessary to carry out design and safety analysis under the most suitable conditions considering foundation and rainfall characteristics. In this study, variations of safety factor were discussed from different aspects to investigate the influence of different parameters of rainfall and analysis conditions. Rainfall and foundation conditions are supposed to be the most sensitive parameters to slope stability, and numerical analysis were performed by changing parameters of the two conditions. Rainfall behavior is based on the domestic statistical rainfall and foundation condition is selected as unsaturated soils. Study results show that, application of rainfall characteristics in different area and parameters of unsaturated soils are responding sensitively to variations of slope safety. Therefore, the input parameters should be fully examined when performing the practical design.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.05a
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• pp.3-34
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• 1998

The stability condition of rock slopes is greatly affected by the geometry and strength parameters of discontinuities in the rock masses. Rock slopes Involving movement of rock blocks on discontinuities are failed by one or combination of the three basic failure modes-plane, wedge, and toppling. In rock mechanics, practically all the parameters such as the joint set characteristics, the rock strength properties, and the loading conditions are always subject to a degree of uncertainty. Therefore, a reasonable assessment of the rock slope stability has to include the excavation of the multi-failure modes, the consideration of uncertainties of discontinuity characteristics, and the decision on stabilization measures with favorable cost conditions. This study was performed to provide a new numerical model of the deterministic analysis, reliability analysis, and reliability-based optimization for rock slope stability. The sensitivity analysis was carried out to verify proposed method and developed program; the parameters needed for sensitivity analysis are design variables, the variability of discontinuity properties (orientation and strength of discontinuities), the loading conditions, and rock slope geometry properties. The design variables to be optimized by the reliability-based optimization include the cutting angle, the support pressure, and the slope direction. The variability in orientations and friction angle of discontinuities, which can not be considered in the deterministic analysis, has a greatly influenced on the rock slope stability. The stability of rock slopes considering three basic failure modes is more influenced by the selection of slope direction than any other design variables. When either plane or wedge failure is dominant, the support system is more useful than the excavation as a stabilization method. However, the excavation method is more suitable when toppling failure is dominant. The case study shows that the developed reliability-based optimization model can reasonably assess the stability of rock slopes and reduce the construction cost.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.2
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• pp.74-83
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• 2001

The purpose of this study was investigate to the influence of forest roads characteristics and environment factors on the soil erosion, stability and vegetation survival of cut slope in forest roads. The results obtained could be summarized as follows; 1. The correlated factors between slope erosion and variables in cut slope were altitude, convex, degree of slope, length of slope and soil depth. In the stepwise regression analysis, length of slope and soil hardness was a high significant and its regression equation was given by -89.6136 + 15.0667X14 + 16.6713X15($R^2$ = 0.6712). 2. The main factors influencing the stability of cut slope were significant in order of coverage, middle, convex, length of slope and north, and its discriminant equation was given by -1.019 + 0.064X22 - 0.808X8 - 0.622X24 + 0.742X11 - 0.172X14 - 0.545X6 ($R^2$ = 0.793). 3. The centroids value of discriminant function in the stability and unstability estimated to 1.244 and -1.348, respectively. The boundary value between two groups related to slope stability was -0.1038. The prediction rate of discriminant function for stability evaluation of was as high as 91.3%. 4. The dominant species of invasion vegetation on the cut slope consist with Carex humilis, Agropyron tsukushiense var. transiens, Calamagrostis arundinacea, Miscanthus sinensis var. purpurascens, and Ixeris dentata in survey area. The rate of vegetation invasion more increased by time passed. 5. The life form of invasion vegetation in cut slop showed to $H-D_1-R_{2,3}-e$ type of the hemicryptophyte of dormancy form, dissem inated widely by wind and water of dissminule type, moderate extent and narrowest extent of radicoid type, erect form of growth form. 6. The correlated factors between forest enviroment and coverage appeared north, passage years and middle position of slope at 5% level. The forest environment factors influencing the invasion plants in survey area were shown in order to altitude, passage years, rock(none), forest type(mixed) and stone amount. The regression equation was given by 17.5228 - 0.0911X3 + 3.6189X28 15.8493X22 19.8544X25 + 0.3558X26 ($R^2$ = 0.4026).

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.54-61
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• 2010

In this research KP-4, one of the plastic mold steels, was coated with the AlTiN from one layer to four layers by the PVD method in the $\Phi$ cemented carbide ball end mill. Coated KP-4 was processed with various conditions. For example, slope of $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ the spindle rotation speed was changed from 10,000rpm to 16,000rpm, the tool feeding speed was changed from 1,300mm/min to 1,700mm/min, the depth of cut was also changed from 0.3mm to 0.9mm, and etc. Cutting component force according to the coating layer number, surface roughness, and the wear of tool were studied.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.4
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• pp.59-69
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• 2007

The scale of a natural disaster grows bigger and bigger every year. The government spends much of its budget on recovering the resulting damage on a national scale. It is important to shift the paradigm from taking measures after a disaster to that of taking preventive actions before a disaster in order to bring a fundamental resolution to such problems. In taking preventive actions and policies, it is necessary to integrate various kinds of advanced technologies including IT, high-tech information gathering technology and operational technology, and to predict and evaluate natural disasters on a comprehensive level. Although Korea is a country with a strong IT sector, most information gathering is still performed in paper. In particular, information about the areas of previous landslide occurrences and slopes remains on paper, which makes it difficult to share the information and to discern the contents, and also raises the possibility of missing documents. Thus this study set out to develop an information gathering and management system for cutting slopes using PDA from the perspective of information gathering, system compatibility, and information management. As a result, field information may be gathered in a variety of forms (location, photos, and texts) real-time. A rough judgment was also made of the stability of rock slopes using the SMR method on the field.

• Journal of the Korean GEO-environmental Society
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• v.5 no.4
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• pp.73-79
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• 2004

Mountain side ditch is constructed at the top of cutting slopes around road and it drains the surface water that flowed from upper part. Mountain side ditch is constructed to keep away the influx of the surface water into cutting faces. However, if Mountain side ditch is constructed on the top of cutting slopes, it is cause of trouble. For example, difficulty of quality control and lack of drainage faculty. Therefore, the faculty and establishment propriety of mountain side ditch are evaluated seriously, according to the condition of ground, topography and rainfall in this paper. Results from the study for the numerical analysis of effect of mountain side ditch indicate that safety factor is enlarged about 3% at rainfall.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.1
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• pp.19-27
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• 2002

To investigate the dominant species and factors related with plant coverage by road structures and forest environment factors, forest roads elapsed from one year to twelve year after construction had been selected in six county(Gochang-gun, Muju-gun, Imsil-gun, Jangsu-gun, Jeongup-shi and Jinan-gun), and 20m segments were continuously set up in each road. The results obtained from this study are summarized as follows: The species diversity of Gochang, Muju, Imsil, Jangsu, Jeongup and Jinan were 1.304, 1.267, 1.308, 1.193, 1.289 and 1.018, respectively. In process of years, plant coverage was increased gradually and average of plant coverage was 15.3% in forest roads which elapsed three year, and was 86.5% in forest roads which elapsed nine year after construction. The dominant species in the cutting slope of surveyed area were covered with Arundinella hirta, Pinus rigida, Miscanthus sinensis var. purpurascens, Artemisia princeps var. orientalis, Pinus densiflora, Oplismenus undulatifolius, Rubus coreanus, Lysimachia clethroides, Lespedeza bicolor, and Alnus hirsuta of the 152 species. The high correlated factors between plant coverage and variables in cutting slopes appeared elapsed year, soil hardness, mean annual precipitation, vertical grade, inslope and arid humidity in surveyed area.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.629-635
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• 2009

In this research, KP-4, one of the plastic mold steels, was coated with the AlTiN from one layer to four layers by the PVD method in the $\Phi$ 8mm cemented carbide ball end mill. Coated KP-4 was processed with various conditions. For example, slope of $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ the spindle rotation speed was changed from 10,000rpm to 16,000rpm, the tool feeding speed was changed from 1,300mm/min to 1,700mm/min, the depth of cut was also changed from 0.3mm to 0.9mm, and etc. Cutting component force according to the coating layer number, and surface roughness were studied. The cutting component force showed a good agreement better the up ward direction than the down ward direction under all experimental conditions. In case of the condition per the material shape, it was lessen when the tool have larger angle because the average effective diameter of the tool is larger. The surface roughness showed good condition in case of the up ward than the down ward direction. And, in the 3rd layer of AlTiN coating, it showed the most suitable condition.

• Proceedings of the Korean Geotechical Society Conference
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• 1994.06c
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• pp.25-48
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• 1994

As Korea is a mountaneous country, many cut slopes are formed along the highways and in housing projects, by cutting through the layers which are composed of shallow soil depth and the underlying hard layers with different degrees of weathering. Such slopes are often foiled by heavy rainfall, and thus its effects on the slope instability are described in detail in. this paper. The importance of discontinuties on the slope stability as well as the effects of rainfall is emphasized for high quality design of cut slopes.