• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.37-46
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• 2013

Many factors about the stability for the reservoir embankments is determined when the facility is completed. Therefore the initial design of the embankment is important. Many researchers focused the effect of soil parameters although the cross section greatly affects the stability and can be controlled in design step. The objective of this research is to analysis of the effects for the safety factor of slope and seepage according to change cross-section in embankment. As a result, the quantity of seepage decreased as the gradient of downstream slope decreased and was proportional to the height of embankments. There was a linear relationship between the gradient of slope and the safety factor of slope. However the gradient of slope did not affect other side slope. All in a relationship, regressive equations with a high correlation coefficient were calculated and can be applied the simple estimation method of the stability using the cross-section. As results of analyzing the sensitivity, the friction angle and permeability critically effect for the slope stability and the seepage, respectively. The effect of the slope gradient was similar to major soil properties.

• Journal of Korean Society of Forest Science
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• v.71 no.1
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• pp.50-54
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• 1985

The effect of relations parameters on the declination gradient of trees was studied in natural forest of Quercus variabilis, Quercus ${\times}$ grosseserrata, Quercus aliens, and Quercus dentata grown at various slope gradient. The declination gradients of trees were effected by the species, slope gradient, and direction of slope, but not effected by density and height in all species. The species shows a superior factor effecting declination gradient of trees compared with other relations parameters, and next effective factor was slope gradient. Especially in all of slope gradient, the declination gradient of Quercus ${\times}$ grossesserrata was highest.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.580-585
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• 2004

The purpose of this study is the stability evaluation of soil slope according to inclination of upper natural slope. Upper natural slope breeds loss of slope by inflow in slope of surface water by rainfal1 and f1uctuation of amount of materials in slope through method of cutting slope according to degree of inclination. Basis of standard inclination does not consider of inclination of upper natural slope and is presented uniformly. Therefore, in this study, analyzed stability of inclination of upper natural slope through limit equilibrium analysis. Result is same as following. First, safety factor through limit equilibrium analysis is almost direct decrease when gradient of soil slope is 1:1.2, 1:1.5. However, when gradient of soil slope is 1:1.0, 1:0.7, if sinclination of upper natural slope are $20^{\circ}$, it shows tendency that decrease of safety factor becomes low rapidly. Second, when when gradient of soil slope is fixed, inclination of upper natural slope increase tendency(maximum 3.0 times) that decrease of safety factor.

• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.2
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• pp.1-12
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• 1996

In order to develope a road landscape that is in harmony with landscaping purpose, degree of sight occupation by slopes at road sides was measured and physical elements composing the slope scenery were visually evaluated and the results are as follows : In analysis of sight occupation ratio by perspective method, gradient of the slopes influenced more on the sight occupation than height did and the driving lane occupied 2 to 3% more proportion of sight than the passing lane. When there is slope at one side of the road, difference in sight occupation between the lanes was increasing with deceased height and with increased gradient of the slopes. In visual analysis of the slope scenery, negative image was increasing with narrow road, increased height and gradient of the slopes. In visual analysis of the slope scenery, negative image was increasing with narrow road, increased height and gradient of the slopes. Particularly, the effect of gradient was critical on scenery. The effect of the slopes was negative at 60$^{\circ}$ or more but positive at 45$^{\circ}$or less gradient. This phenomenon was more conspicuous with wide 4 lane roads than wide 2 lane roads. Although direct comparison is difficult due to a great difference between Korea and U.S.A. in climate, land condition, road dimension, and public process of purchasing land, etc, it is desirable to treat road sides so that the scenery is in harmony with landscape around as well as emphasizing the regional characteristics, also giving friendly and comfortable image to drivers and nearby residents in addition to safety as can be seen in U.S.A.

• Journal of Forest and Environmental Science
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• v.30 no.1
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• pp.71-75
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• 2014

Forest roads failure is one of the most common problems caused by heavy rainfalls. This study investigated the characteristics on stabilization measures installed for cutting slopes failure of forest road resulted from heavy rainfalls. Three primary factors (slope length, slope gradient, soil type) affecting cutting slope failure were considered and stabilization measures were classified into two types (A type: wooden fence, vegetation sandbag, stone masonry; B type: wire cylinder, gabion, concrete retaining wall) through discriminant analysis based on their capacity of resistance to slope failure. Results showed that A type was mainly installed in such conditions as cut slope <8 m, cut slope gradient $30-40^{\circ}$ and soil type with soil while B type occurred in locational conditions as cut slope length >8 m, cut slope gradient < $30^{\circ}$ and > $30^{\circ}$, and soil type of gravelly soil and rock.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.1
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• pp.35-43
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• 2000

The slope gradient of the Korean Peninsula was analyzed by using DEM(DTED level 1). The Peninsula has high percentages of gentle slopes. But low plains and very steep slope regions are scarcely distributed in the Peninsula. Altitude lower than 150m areas are composed of plains and undulated plains. The steepest and most rugged topographies are observed in the range of altitude from 500m to 1,000m areas. The areas of altitude greater than 1,000m show plateau landscapes. By overlapping digital geology maps and the gradient grade maps, We revealed the characteristics of slope regions by geological districts. High latitude with steep slope are well developed in the geological districts of granitic gneiss(ARgr) and gneiss($PR_1$) of the Pre-Cambrian, sandstone of the Paleozoic era(P-T), and sedimentary rocks of the Mesozoic era($J_2$). Low altitude with gentle slope areas are representative in the districts of granite of the Mesozoic era($Jgr_1$), the Cretaceous sedimentary rocks of the Mesozoic era($K_1$, $K_2$) and the Cenozoic strata(N). Basalt extruded the Quaternary($Q_1$) are observed in the areas of very gentle slope but greater than 1,000m altitude.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.877-881
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• 2012

This research was carried out to investigate the interaction effect of slope gradient and rainfall intensity on soil loss with rainfall simulator. The soils used in this experiment were saprolite, Chahang series which distributed extensively in Daegwanryong. Slope gradient applied was 0.5, 7, 15 and 30%. Rainfall intensity applied was 20, 60 and $90mm\;hr^{-1}$. The result obtained can be summarised as follow; Overall, Chahang series suffered more losses than saprolite. Chahang series shows the immediately large increase of soil loss with the increasing soil gradient and rainfall intensity. However, saprolite shows a little increasing loss up to 7% gradient and abruptly increasing loss logarithmically over 7% gradient in soil slope. In combination of slope gradient 15, 30% and rainfall intensity 60, $90mm\;hr^{-1}$ processing, both soil erosion happened significantly. And there was no significant difference between the two soils. Because Chahang series have the danger of soil loss with low slope gradient and rainfall intensity, we should give greater attention to soil management in Chahang series.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.2
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• pp.47-52
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• 2000

This study was carried out to analyze the effects of elapsed years and physical properties on fill-slope alignment of forest road. For the study, 21 forest roads in Puy$\check{o}$-gun and Asan-shi of Chungchungnam-do were selected and fifteen factors that might influence on fill-slope alignment were analyzed. The major forms of alignment of the fill-slope in the time of construction were concave and compound. But, with the elapsed years, the concave and compound forms have decreased and linear and convex forms have increased. And fill-slope alignment was strongly related with fill-slope distance, fill-slope gradient and ground gradient among the physical properties.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.735-738
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• 2005

The purpose of this study is the infiltration characteristics of soil cut-slope by rainfall. Stability analysis of soil cut-slopes has been conducted by limit equilibrium method on Seep/w and finite element method on Slope/w. Result is same as following. First. the hour when seepage line and groundwater in contact is proportionate from rainfall rate condition and upper natural slope gradient condition which is identical. Second, when seepage line and groundwater is contact, seepage line moves gradually at soil cut-slope surface. Finally, seepage line is formed similarly with soil cut-slope gradient. Third, when rainfall is ended, from the recording upper natural slope where the hour will pass it is stabilized

• Journal of Ocean Engineering and Technology
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• v.20 no.6 s.73
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• pp.61-66
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• 2006

Two iterative solvers are applied to solve the modified mild slope equation. The elliptic formulation of the governing equation is selected for numerical treatment because it is partly suited for complex wave fields, like those encountered inside harbors. The requirement that the computational model should be capable of dealing with a large problem domain is addressed by implementing and testing two iterative solvers, which are based on the Stabilized Bi-Conjugate Gradient Method (BiCGSTAB) and Generalized Conjugate Gradient Method (GCGM). The characteristics of the solvers are compared, using the results for Berkhoff's shoal test, used widely as a benchmark in coastal modeling. It is shown that the GCGM algorithm has a better convergence rate than BiCGSTAB, and preconditioning of these algorithms gives more than half a reduction of computational cost.