• Journal of The Geomorphological Association of Korea
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• v.20 no.4
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• pp.1-13
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• 2013

Padori beach is one of the representative composite mixed beach in Korea and shows divert geomorphic landscape change. It belongs to the Taean National Park. The purpose of this study is to clarify movement mechanism of sediments from sediment distribution of Padori beach associated with morphology. In addition, it is to explain morphological landscape change under different wave and tide condition in the composite mixed beach consisting of a dissipative low tide terrace and a reflective beach face with a high tide range of 5 to 7m. The results of this study are: First, the mean grain size of sediments becomes smaller from the south of the beach, where there is a wide wave-cut platform, to the north because gravels are supplied from the wave-cut platform as well as sea-cliff in the south of the beach. A sedimentation pattern of the sandy gravel on the beach face and gravel on the berm, and gradation phenomena of grain size on cross-shore and alongshore direction in the beach can be explained with a pattern of sediment movement, overpassing, in the composite mixed beach. Second, micro-topography on beach face and berm were changed depending on effects of wave height and tide. As a result, in low-wave energy environments, a berm is developed in large size, and beach cusps are formed on the upper beach face, while in high-wave energy environments, a berm is built up in relatively small size, and mixture of sediments occur on the upper beach face.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.1
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• pp.112-121
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• 1997

The aim of this study was to analyze the slope stability relating to the failure of cut slopes and the characteristics of stress-strain relations obtained by limit equilibrium method, finite element method, and stereographic projection method for the reinforced cut slopes. The following conclusions were made : 1.To use stereographic projection method led to little possibility to take the toppling and wedge failure while to use the other methods led to the failure. It was recommended to reduce the slope inclination from 1:1 to 1: 1.5~1 :1.8 and adopt coir mesh method to protect the slope surface. position with the horizontal displacement after final excavation moved to the excavation base. The maximum shear strain values concentrated at the excavation base indicated the possibility to induce the local failure. 3. It was recommended that the slope inclination for blast rock with the slope height larger than l0m was 1: 0.5, 1:1, and 1: 1~1 :1.5 for hard rocks, soft and ordinary rocks, and ripping and soils, respectively. 4. Berm width criteria for blast rock with the slope height larger than l0m were recommended as follow : 2~3m per 20m slope height for hard rocks, 1 ~2m per l0m slope height for soft and ordinary rocks, 1 ~ l.5m per 5m slope height for ripping and soils.

• Journal of Korean Society of Forest Science
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• v.105 no.2
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• pp.223-230
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• 2016

This study was carried out to investigate the quarrying and restoration characteristics on quarry in Korea. We researched quarrying and restoration status, analyzed the relationship between restoration area and permitted period, permitted area, quarrying volume, pit slope width, height, and berm width from 55 quarry sites. Most of the quarries were located in the following conditions : mixed forest, average altitude of less than 300 m, average mountain slope of $61^{\circ}$<, hillside, granite and landslide hazard class. Major quarrying characteristics were permitted period of 6~10 years, permitted area of less than 10 ha, quarrying volume of less than $1,000,000m^3$, a stone type of aggregate, a quarrying type of terrace, pit slope of $61^{\circ}$< Most quarries were restored by themselves, and the main restoration type was slope greening. Also, area ratio of flatland, pit slope, and berm was 54.9:39.6:5.5. Ccorrelation analysis showed that quarrying area was positively correlate with quarrying volume (${\alpha}=0.01$), permitted area, pit width, and pit height (a=0.05).

• Journal of the Korean Geosynthetics Society
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• v.14 no.1
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• pp.51-58
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• 2015

The counter weight filling is a technology to accumulate soils on the side of berm with a proper width and height for improving the stability of the embankment. This study aims to assess a feasibility of the counter weight filling in the construction of pavement roads for recovery of shear failure during the construction. An effective counter weight filling section was suggested using the numerical analysis. The results showed that the effective counter weight filling section is two-fold (x2) higher than the ratio of width in counter weight filling : embankment height and one third (1/3) to the ratio of height in counter weight filling : embankment height. Also a range of effective trench crossing the counter weight filling required when a trench crossing counter weight filling is installed was suggested by supplying a proper distance between the counter weight filling section and cross-sectional trench.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.737-752
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• 2013

This study was conducted to evaluate the allelopathic effect of aqueous extract of Ganghwa domestic mugwort (Artemisia spp.) on vegetables and its related allelo-chemicals. When the receptor vegetables, such as Chinese cabbage, lettuce, and red radish, were treated with aqueous extract obtained from Sajabalssuk (A. $sp^*I$), Ssajuarissuk (A. $sp^*II$) or Ssajarissuk (A. $sp^*III$), their germination rate, leaf number, plant height, and root length were restricted with increasing concentration of aqueous extract. Allelopathic effect was the highest in radish, than lettuce and Chinese cabbage in order. The growth of topplant were more inhibited then root growth observing in restriction of plant height, root length, and chlorophyll contents. The plant height, the root length of red radish were 53.3 and 61.2% and their fresh weights were 19.8 and 26.4% compared to those of controls, respectively. A. $sp^*III$ showed the highest allelopathic effect among the donor plants. In HPLC analysis, 7 phenol compounds were identified in A. $sp^*I$ and A. $sp^*II$, and, in A. $sp^*III$, and hydroxybenzoic acid and phenylacetic acid were further identified as allelochemicals. It is considered that their plant growths were variously inhibited by the amounts and types of allelochemicals in aqueous extracts. To increase the productivity of farm land after cultivation of mugwort, these results can be useful to select the following field crops.

• Tunnel and Underground Space
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• v.20 no.5
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• pp.360-368
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• 2010

The paper presents a case study from a surface mine where the controlled augmentation of throw and drop of the blasted muck piles was warranted to spread the muck piles on the lower berm of the bench. While the augmentation of throw increased the lateral spread and the looseness of the broken muck, the augmentation of drop significantly lowered the muck pile height for easy excavation by the excavators. In this light, the present paper highlights and discusses some pertinent changes in the blast design parameters for such specialized application of cast blasting in a surface mine, where a sandstone bench, with average height of 22-24 m was to be made amenable for excavation by 10 m3 rope shovels, which possessed maximum digging capability of up to 14 m. The results of tailoring the blast design parameters for augmentation of throw and drop are compared with the baseline blasts which were earlier practiced on the same bench by dividing the full height of the bench in 2-slices; upper slice (10-14 m high) and lower slice (12-15 m high). Results of fragment size, its distribution and total cycle time of excavator (shovel) are presented, and discussed.

• Journal of Korean Port Research
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• v.8 no.2
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• pp.37-56
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• 1994

The effects of wave energy focusing by a submerged berm type of structure is examined. The fundamental idea is based on the phenomenon of refraction by a lens-shaped crescent structure which results in the focusing of wave energy on the center line of the structure. The shape of the submerged structure is a complex curve combining circular with elliptical elements. Based on the design procedure, a special configuration of structure(termed herein as a triple crescent structure) is introduced. Next, some hydraulic model tests are performed to confirm the wave focusing effect in laboratory. In addition, in order to interpret the wave focusing performance behind the structure, a numerical procedure by the hybrid element method is used on the basis of the conventional mild slope equation but modified and extended to allow for steeper bottom slopes and higher curvature. The modified refraction and diffraction provide additional mechanism for wave height amplification and the maximum amplification for triple crescent structure is presented. It also allows for the possibility of wave energy scattering with the change of the incident wave direction. Comparisons with previous theoretical results involving a submerged crescent shape structure are described.

• Korean Journal of Medicinal Crop Science
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• v.21 no.3
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• pp.179-183
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• 2013

This study was carried out to investigate the variation of growth and yield using different planting densities and vinyl mulching in S. miltiorrhiza cultivation. Top plant growth was observed in the $30{\times}30cm$ planting density of S. miltiorrhiza;, plant height, leaves and branches were larger than in the other treatments. Root length, root diameter, and supporting roots of underground part were increased as planting density was wide, and dry root weight was increased in $30{\times}30cm$. However, yield was highest at 294 kg/10a in the planting density of $30{\times}10cm$. The use of 30-31cm white and black vinyl mulching had no significant effect on the plant height of S. miltiorrhiza, as compared to non-mulching. However, the highest volume of leaves and plant weight was observed in plants using 24.7 black vinyl mulching. Dry underground root weight was highest in black vinyl mulching at 21.7 g compared to 17.0 g for non-mulching. Yield per 10a increased by 28% using black vinyl mulching compared to non-mulching. Based on the results of this study, planting density of $30{\times}10cm$ and black vinyl mulching are the most suitable in the cultivation of S. miltiorrhiza.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.5
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• pp.207-216
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• 2018

This research compared and analyzed safety ratio of slope with Talren97 and SoilWorks based on limit equilibrium analysis and Midas GTS based on finite element analysis. For the analysis variables, there are slope height, berm condition, soil parameter, groundwater level, slope inclination. All of slope stability analysis were performed by dividing into dry season and rainy season. As the result of the analysis of Talren97 and SoilWorks based on same theory, safety ratio of slope shows same value, so there was no difference between the programs. In comparison with limit equilibrium analysis, the result of finite element analysis showed somewhat high ratio of safety and it was higher by about 2.4% averagely. The difference between the result of limit equilibrium analysis and that of finite element analysis is in the range which can ignored in practical work.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.4
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• pp.213-217
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• 1999

The river bank is one of the most important structure of fluvial hydraulic structure. Because the breaking of river bank is the cause of calamity, the durability and stability of river bank an very important factors. The breaking of river bank is the cause of the overflow of flood and the leakage of river bank. In this study, we investigated the leakage of river bank using the resistivity probing and estimated the volume of leakage using the weighted residual method The study basin of this study is the upstream of Sumji river basin and the factor of river bank is length 300 m and berm 2.0 m and width 4.5 m and height 4 m. We evaluated the leakage of river basin using using the resistivity probing and estimated the leakage volume using the weighted residual method. The result of this study, the leakage of river bank generated at the point of 39~45 m 80~90 m. 218~222 m. 214~250 m and the type of leakage is the rectangle and the polygon. And the leakage volume of this points evaluated 2.7$\times$$10^{-3}$ $\textrm{m}^3$/sec.