• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1053-1059
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• 2009

In this study, slope hazards mitigation methods for a natural terrain are systematically classified to survey the mitigation methods and develop a data base system. Also, field survey sheets which can be recorded the features of mitigation methods installed in the natural slope are developed. The slope hazards mitigation methods in the natural slope are classified as hillside part method and valley part method. The slope part sheet and the valley part sheet are also drawn up for field survey. As the result of the filed survey of mitigation methods about 50 points in Muju and Jangsu area, grass painting and slope covering methods are dominant in case of slopes part. In case of valley part, slit dam, concrete check dam and slope foot barrier are applied simultaneously.

• Korean Journal of Environment and Ecology
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• v.8 no.2
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• pp.154-159
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• 1995

The Chuwang valley-Kumunkwangi valley forest in Chuwangsan area was studied to investigate forest structure in relation to altitude and part of slope. Forty eight quadrats were set up in the valley forest along altitude of 470m to 780m and part of the slope. Density and basal area of trees in tree strata decreased as increasing elevation. With increasing elevation the importance values of Quercus mongolica, Fraxinus rhynchophylla increased, while those of Pinus densiflora, Lindera obtussiloba decreased. As going from lower part to upper part of the slope, the importance values of Quercus valiabilis and Lindera obtussiloba increased while those of Fraxius rhynchophylla, Acer mono decreased. Species diversity tended to decreased as going to upper parts of the slope. The range of similarity indices between elevation belts, and parts of the slope were 74.4~84.2% and 68.0~96.3%, respectively. According to importance value and cluster analysis, the studied valley forest was classified into three forest communities of Pinus densiflora-deciduous tree species community of lower part of slope, Pinus densiflora-Quercus variabilis community of middle and upper part of slope, Pinus densiflora community of the top area.

• The Journal of Engineering Geology
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• v.32 no.2
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• pp.209-219
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• 2022

To experimentally investigate the variation of soil characteristics in slope during rainfall and the shape of slope failure, the model test was performed using soil box and artificial rainfall simulator. The model test of slope formed by the homogenous sand was performed, and the saturation pattern in the model slope due to rainfall infiltration was observed. The slope model with the inclination of 35° was set up on the slope of 30°, and the rainfall intensity of 50 mm/hr was applied in the test. The soil depth of 35 cm was selected by considering the size of soil box, and the TDR (time domain reflectometry) sensors were installed at various depths to investigate the change of soil characteristics with time. As the result of model test, the slope model during rainfall was saturated from the soil surface to the subsurface, and from the toe part to the crest part due to rainfall infiltration. That is, the toe part of slope was firstly saturated by rainfall infiltration, and then due to continuous rainfall the saturation range was enlarged from the toe part to the crest part in the slope model. The failure of slope model was started at the toe part of slope and then enlarged to the crest part, which is called as the retrogressive failure. At the end of slope failure, the collapsed area increased rapidly. Also, the mode of slope failure was rotational. Meanwhile, the slope failure was occurred when the matric suction in the slope was reached to the air entry value (AEV) estimated in soil-water characteristic curve (SWCC).

• Korean Journal of Environment and Ecology
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• v.9 no.2
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• pp.126-132
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• 1996

The Gugogdong-Horyongbong valley forest in Odaesan National Park area was studied to investigate forest structure in relation to altitude and part of slope. Forty-eight quadrats were set up in the valley forest along altitude of 800m to 1,500m and part of the slote. With increasing elevation the important values of Quercus mongolica and Rhododendron schlippenvachii increased, while those of Abies holophulla, Ulmus davidiana var. japonica and Lindera obtusiloba decreased. As going from lower part to upper part of the slope, the importance values of Quercus mongolica and Rhododendron schlippenbachii increased while those of Acer mono and Ulmus laciniata decreased. Species diversity tended to decreased as increasing elevation. The range of similarity indices between elevation belts, and parts of the slope were 56.3~73.4% and 61.9~71.8%, respectively. According to importance value and cluster analysis, the studied valley forest was classified into tree forest communities of Abies holophulla-deciduous tree species community in lower and middle parts of slope at low and middle elevation belts, Quercus mongolica- coniferous tree species community in upper part of slope at low and middle elevation belts and lower and middle parts of slope at high elevation belt and Quercus mongolica community in upper part of slope at high elevation belt and top area.

• Korean Journal of Environment and Ecology
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• v.16 no.4
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• pp.457-464
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• 2003

A valley forest in Sangbuun area at Jirisan National Park was studied to investigate forest structure in relation to altitude and part of the slope. Forty-eight quadrats were set up in the valley forest along altitude of 726m to 1,090m and part of the slope, and vegetation analysis for the woody species in the tree and subtree layers were carried out. With increasing elevation belt, mean DBH, height and basal area of the trees in the tree layer increased while their density decreased. This trends may be caused by the disturbance which was relatively severe in the low elevation area. As elevation increased, the importance percentages of Fraxinus rhynchophylla, Quercus variabilis and Quercus mongolica increased while those of Styyax japonicus, Carpinus laxiflora and Pinus densiflora decreased. The importance percentages of Quercus variabilis and Pinus densiflora increased as going from lower part to upper part of the slope. However, the opposite trend was found for the importance percentages of Acer mono and Corlus heterophylla var. thunbergii. Number of species and species diversity decreased as increasing elevation and going from lower part to upper part of the slope. According to importance percentage and cluster analysis, the valley forest was classified into three forest communities of Quercus serrata-broad-leaved tree species community in lower part of the slope at low elevation belt, middle elevation belt and middle and upper parts of the slope at high elevation belt, Pinus dnsiflora-Quercus serrata community in middle and upper parts at low elevation belt, and Quercus mongolica-broad-leaved tree species community in lower part of the slope at high elevation belt and top area.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.45-52
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• 1993

Surveyed results on the slope of grain and the twist of sawn lumber of Pinus koraiensis, Larix leptolepis, and Pinus densiflora were summarized as follows: 1. The slope of grain of Pinus koraiensis has a Z-grain in the stem axis. The slope of grain was found to be the lowest at near to the pith and then constantly increased. At the height of 0.2m from the base of stem. a cross section of 35 annual rings was found to have a repeatedly increasing and decreasing slope of grain and then constantly decreased. At the height of 1.2m to 7.2m from the base of stem, the slope of grain increased conspicuously until the 10th annual ring, after which it increased near to the bark with repeatedly increasing and decreasing trends. 2. Pinus densiflora has a S-grain in the stem axis. The lowest slope of grain was found at near to the pith, and the highest in the 10 to 35 annual rings from the pith. 3. Larix leptolepis has a S-grain. At the height of 3.2m from the base of stem, the big fluctuation of the slope of grain was found without any particular trend. 4. The slope of grain and the twist between natural and reforested timber of Pinus koraiensis were found to be almost the same trend in viewpoint of the annual ring. The maximum slope of grain of imported Siberian timber of Pinus koraiensis was found at the 10 annual rings, which was quite similar to that of native species in Korea, but the big difference of the twist was found at 140 annual rings. 5. The twist was little at the mature wood of reforested Pinus koraiensis and Siberians and the duplicated part of mature and juvenile woods of those. On the contrary, the twist was great at the duplicated part of mature and juvenile woods of Pinus koraiensis. 6. The twist of Larix leptolepis showed the S-direction which coincided with that of slope of grain. The twist was greatest at the part of juvenile wood and little at the duplicated part of mature and juvenile woods, and little difference of twist was found between mature and juvenile woods. 7. Siberian larix having a minimum slope of grain showed the lowest twist, and the twist at the duplicated part of mature and juvenile woods showed a middle level of both mature and juvenile woods' portions.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.181-186
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• 1994

The Shindae resting place-Jibong valley forest in Tokyusan area was studied to investigate forest structure in relation to altitude and part of slope. Forty eight quadrats were set up in the valley forest along altitude of 750m to 1,247m and part of the slope. Density of trees in tree strata decreased as increasing elevation, and mean DBH of trees in tree strata increased as increasing elevation. With increasing elevation the importance values of Quercus mongolica, Acer mono, Fraxinus mandshurica increased, while those of Quercus serrate, Betula schmidtii decreased. As going from lower part to upper part of the slope, the importance values of Quercus mongolica and Symplocos chinensis for. pilosa increased while those of Cornus controversa and Fruxinus mandshurica decreased. The number of species, species diversity and evenness tended to decreased as increasing elevation. The range of similarity indices between elevation belts, and parts of the slope were 55.3~67.1％ and 36.8~71.7%, respectively. According to importance value and cluster analysis, the studied valley forest was classified into four forest communities of Quercu serrata community of lower part of slope of low elevation belt, Quercus mongolica-Quercus serrata community of middle and upper part of slope of low elevation belt, Quercus mongolica-deciduous tree species community of middle and high elevation belt and Quercus mongolica-Rhododendron schzippinbachii community of the top area.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.3
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• pp.47-62
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• 1993

The laboratorv model test was carried out to investigate the behavior of pore water pressure, the critical amount of rainfall for slope failure, the pattern of failure, and the variation of seepage line at the slope with the uniform material of embankment by changing the slope angles and rainfall intensities. The results were was summarised as follows : 1.At the beginning stage of rainfall, the negative pore pressure appeared at the surface of slope and the positive pore pressure at the deep parts. But, the negative one turned into the positive one as the rainfall continued and this rapidly increased about 50 to 100 minutes before the slope failure. 2.The heavier the rainfall intensity, the shorter the time, and the milder the slope, the longer the time took to reach the failure of slope. 3.As the angle of the slope became milder, the critical amount of rainfall for slope failure became greater. 4.Maximum pore water pressure was 10 to 40g/cm$^2$ at the toe of slope and 50 to 90g/cm$^2$at the deep parts. 5.In the respect of the pattern of slope failure, surface failure of slope occurred locally at the toe of slope at the A-soil and failure of slope by surface flow occurred gradually at the top part of slope at the B-soil. 6.As the rainfall continued and the saturation zone in the embankment was formed, the seepage line went rapidly up and also the time to reach the total collapse of slope took longer at the B-soil. 7.As the position of the seepage line went up and the strength parameter accordingly down, the safety factor was 2.108 at the A-soil and 2.150 at the B-soil when the slope occured toe failure. Minimum safety factor was rapidly down to 0.831 at the A-soil and to 0.936 at the B-soil when the slope collapsed totally at the top part of slope.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.1 s.108
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• pp.33-48
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• 2005

The purpose of this study was to discover the landscape visual image of the slope scene and their harmony with surrounding sceneries. This research utilized the basic study tool of psycho-physics and processed the case study of ten types of slope construction scene along the highway. The analysis was performed by the data obtained from the questionnaires and the photos for the slope construction scene. The questionnaires for analysis the image of the slope construction scene and their harmony with surrounding sceneries were designed using semantic differential scale and 5 point Likert-scale. The major findings were as follows. 1. At the part of the visual preferences analysis, the slope revegetation methods showed high level of preferences generally than on the slope structure methods. While the slope revegetation methods were estimated friendly, continuity, harmonious, soft, light and wide, the slope revegetation methods were estimated unstable, female, static, simple, omnipresent, appeared as policeman of weak inclination. Also the slope structure methods were estimated stable, manly, complicated, steep and healthy but rough, unharmonious, unfamiliar and heavy. 2. Psychological factors, related to the satisfaction for the slope revegetation methods were composed of three factors, aesthetic, individuality and physical character. And the slope structure methods were composed of five factors, aesthetic, individuality, stability, physical character, and complexity. 3. At the part of harmony with surrounding landscapes, the slope revegetation methods were evaluated highly but the slope structure methods received the lowest evaluation. Also the harmony analysis with surrounding view on the slope revegetation methods showed degree of high more than average in all texture, form, color and scale but the slope structure methods showed degree of fewer than average degree in form, scale, color and texture.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.4
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• pp.387-400
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• 2013

In this study, the slope stability analysis and the landslide hazard assessment in tunnel portal slope were carried out. First, we selected highly vulnerable areas to slope failure using the slope stability analysis and analyzed the slope failure scale. According to analyses results, high vulnerable area to slope failure is located at 485~495 m above sea level. The slope is stable in a dry condition, while it becomes unstable in rainfall condition. The analysis results of slope failure scale show that the depth of slope failure is maximum 2.1 m and the length of slope failure is 18.6 m toward the dip direction of slope. Second, we developed a 3-D simulation program to analyze characteristics of runout behavior of debris flow. The developed program was applied to highly vulnerable areas to slope failure. The result of 3-D simulation shows that debris flow moves toward the central part of the valley with the movement direction of landslide from the upper part to the lower part of the slope. 3-D simulation shows that debris flow moves down to the bottom of mountain slope with a speed of 7.74 m/s and may make damage to the tunnel portal directly after 10 seconds from slope failure.