• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.2
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• pp.72-79
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• 2010

This research was initiated to investigate the revegetation characteristics under seedling types of native woody plants on a disturbed slope. 4 different seedling types of woody plants (control, unit seedling plot, nature seedling plot, pot seedling plot) with the same woody plants (Rhus chinensis Mill, Albizzia julibrissin Duraz., Quercus acutissima Carr., Pinus densiflora S. et Z.) were treated with 3 replications on the experimental disturbed slope. Data such as the died number of native woody plants, growth height and visual quality were analyzed. The died number of plants were high in unit seedling plot when compared to the rest plots of seedling types. From the standpoint of died plant species, the died number were high in Rhus chinensis and Albizzia julibrissin whereas the died number were low in Quercus acutissima and Pinus densiflora. That's because we used 1-year old seedlings of Rhus chinensis and Albizzia julibrissin and 3-year old seedling Quercus acutissima and Pinus densiflora. This result indicated that the died reason of native woody seedling was not species but seedling age. Both growth height and visual quality were ranked first in the pot seedling plot, second in the nature seedling plot, third in the unit seedling plot, and last in the control plot, respectively. However, the difference of both growth height and visual quality in each seedling plot was not observed on the 11 months after planting. Especially, the main reason of low rooting and growth value in the unit seedling plot was due to wooven fabric outer crust of pot that obstruct seedling rooting into the soil. We concluded that pot seedling of native woody plants was effective in the viewpoint of the ecological disturbed slope revegetation.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.277-284
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• 1999

This study describes the influence factors related to slope failure pattern and dimension in the southern Kyounggi area. Intrusive and metamorphic rocks are distributed in the study area. Geological condition, rainfall property and slope geometry are influence on slope failure characteristics in the study we& Geological factors related to slope failure are rock type, geological structure and weathering condition. Because of deep soil (RS-CW) depth of granite region, circular failure type is major failure pattern in granite region. Almost granite slopes with circular or surface failure pattern are failed during heavy rainfall season. But typical wedge failure type related to geological structure factor is a main failure pattern of metamorphic rock slope. Additionally failure dimension is influenced by geological factors and several factors, i.e. natural slope condition, failure type, rainfall intensity and etc. failure height/width ratio and thickness/length ratio of granite slope are 0.88 and 0.23. But the ratios of metamorphic rock slope are 1.36 and 0.19.

• Journal of the Korean Society of Safety
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• v.31 no.2
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• pp.70-75
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• 2016

Recently, coastal erosion has been widely in progress and the erosion level becomes also serious in the world wide, espeically in East Sea in Korea. Since it would threaten the life, economics and security risk, it is necessary to much comprehend the reason why coastal erosion has occurred according to the geographical characteristics. Meanwhile, analysis about hydrodynamics of the solitary wave such as tunami in swash zone is needed for the best management practice of coastal erosion. Solitary wave is nonlinear wave and can be reproduced in the laboratoy scale by openning suddenly a sluice gate with water head difference, of which methodology was found in the literature, since it could be simply determined by a significant wave height. Thus, in this sutdy the generation of solitary wave was experimentalized using the sluice gate. Experimental conditions were classified by angles of a beach slope, a water level in a beach slope and a difference of water level between in a headtank and a channel bed. Two kinds of dimensionless analyses based from experimental results in this study were presented; the first analysis indicates nondimensionalization between the wave height and the water level in a beach slope in order to investigate characteristics of solitary wave approaching the beach. The second shows the other nondimensionalization between dynamic pressure and static pressure on a beach slope to investigate the relationship between wave breaking and wave pressure. Under the same conditions as laboratory experiments, the numerical results computed with a SWAN model embedded in FLOW 3D were compared in terms of wave height, and pressure on the beach slope, which shows good agreement with each other. Overall results from this study could provide fundamental hydraulic data for the reliabile verification of numerical simulation results about coastal erosion in swash zone caused by solitary waves.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.06a
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• pp.33-42
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• 2003

Since the cut slope has been big concern due to frequent failures, the government decided to include cut slopes in the“Act for Safety Control of Public Structures”. Based on the Act, the cut slope whose height is over 50m and length is over 200m should be inspected on the regular basis. According to the Act, KISTEC developed the objective evaluation method for the condition of cut slope. The evaluation method is divided into two categories: evaluation for damaged condition and evaluation for failure affecting factor. Based on the evaluation results, the cut slope is graded from A to E. In this study, the process to evaluate the cut slope condition and the evaluation criteria to divide the grade of cut slope are introduced.

• Journal of Korea Water Resources Association
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• v.51 no.4
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• pp.313-322
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• 2018

The height of the steps was almost the same as the grain size of bed materials and increased with channel slope. The step widths and step wavelengths are almost the same size, and the step wavelength was decreased when the channel slope was increased. It was analyzed that there was a clear correlation between channel width and step width, and the step width increases with channel width. In addition, the step wavelength was scaled by channel width, and the step height is governed by the grain size of the rock forming the step, so that the profile structure of the step-pool was changed according to the channel slope. the scale of the pool was found to be highly correlated with the channel width, grain size, and slope gradient. Therefore, the characteristics of step-pool structure in mountain streams were influenced by various factors, but it can be explained as the grain size, channel width and channel slope.

• Journal of the Korean Geotechnical Society
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• v.35 no.5
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• pp.31-41
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• 2019

This paper demonstrates safety factor for effective planning at initial stage by utilizing results on changes of safety factor according to various conditions of slop and examines impacts of factors that affect slope safety factors as well. Firstly, it describes shear strength which satisfies minimum allowable safety factor: 1.20 depending on height and slope. As the height increases by 5.0 m, the safety factors decrease by 0.04 while it tends to consistently reduce by approximately 20%, 30% and 40% after height goes to 10.0 m. As slope reduces by about 0.3, the safety factors increases by 0.4, which shows the rate of safety factors on slope grows by about 10%, 20% and 30% on lowering slope. When cohesion goes up by 10.0 kPa the safety factors increases by around 40% respectably while the angle of internal friction grows by $5^{\circ}$, it increases by about 8%. The rate of safety factors is identified as $Fs=3.86H^{-0.59}$, Fs = 0.43 s, Fs = 0.04 c, $Fs=0.02{\phi}$ depending on height, slope and shear strength. The safety factor with rainfall infiltration tends to increase by 18% compared to the condition of saturated surface on earth.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.321-324
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• 2008

Forest fire danger rate of thinning area was lower than that of non thinning area, because height rate of leewardside in burned stem of tree, damage rate of crown and mortality of tree in thinning area were 30.8%, 37% and 48.4% lower than that in non-thinning area, respectively. Intensity of forest fire varied depending upon topographical condition up slope, down slope, aspect, location as well as species, breast height diameter and forest tree density. Especially, a mountaintop area was burned down when forest fire was spread to up slope ridge of mountain.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.263-266
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• 2007

In this paper, analysis results on the failure of slope behind a Plant Complex of Gimhae due to typhoon Rusa in 2002 are introduced. The left side of the slope was reinforced by soil nails and the right side of the slope was going to construct slope reinforcement works. In the slope failure, the damage area is about $34,000m^2$, the lower width of slope failure is about 230m, the upper width of slope failure is about 50m, and the height of slope failure is about 120m. The elevation of a bedrock in the right side of the slope was lower than the left side of the slope. Due to the depth of weathered soils and weathered rocks in right side of the slope was thick, it will be expected that the effects of pore-water pressure during the rainfalls are large. For the analysis of the failure mechanism, 3-dimensional numerical analysis was carried out by FLAC-3D.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.722-726
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• 2010

Inventory survey is process collecting data about cut slope. It's different from inspection. It contains not only basic information about cut slope, especially location, GPS positioning, height, length, weathering, joint direction, water conditions but also level of danger and damage. Collected data are being used get at status about cut slope along national roads. And It helps judging about priority of detailed investigation. According to results of analysis, we found better method about maintenance of cut slope. Later on, if inventory research is finished, we will understand characteristics of collapse slopes.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.4
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• pp.105-120
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• 1991

This study was performed to investigate the minimum safety factor of embankment in consideration of seismic coefficient by the psuedo-static analysis The variables were cohesion, the internal friction angle, angle of slope, height of seepage, height of embankment, depth of replacement The results obtained were compared with those by Fellenius method, simplified Bishop method and Janbu method. The results were summarized as follows: 1.The increasing rate of the minimum safety factor with the increasing of cohesion appeared larger in Fellenius method and Bishop method than in Janbu method. And that with the increasing of the internal friction angle appeared the lowest value in Janbu method. The minimum safety factor was influenced larger on the internal friction angle than on cohesion. 2.The variation of the minimum safety factor with the height of seepage at 0m and 5 m was nearly similar to Fellenius method, Bishop method and Janbu method. On the other hand, it was decreased suddenly at 25 m. 3.The minimum safety factor with the height of embankment was decreased remarkably under 10 m with the increasing of seismic coefficient. But, it was decreased slowly more than 10 m. As the height of embankment was low, the influence of cohesion appeared larger. 4.In heigher case of the depth of replacement, the phenomenon of reduction of the minimum safety factor appeared remarkably with seismic coefficient increased. And in lower case of the depth of replacement, the minimum safety factor was similar in Fellenius method and Bishop mehtod. But it appeared larger in Bishop method and Janbu method than in Fellenius method with the depth of replacement increased. 5.As the cohesion and the internal friction angle were large, the phenomenon of reduction of the minimum safety factor with the increasing of seismic coefficient appeared remarkably. Also, the influence of seismic coefficient in minimum safety factor appeared larger with the soil parameter increased. 6.When the seismic coefficient was considerated, investigation of the structural body on the slope stability appeared profitably in Fellenius method and Janbu method than in Bishop method.