• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2000.09a
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• pp.183-193
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• 2000

A series of studies such as geological logging data analysis, detailed geological survey, rock mass evaluation, in-situ and laboratory tests, rock strength and mechanical properties of the rock were concerned. The stability of the slope were carried out inorder to design the pit slope and individual benches using the stereographic projection analysis and numerical methods in Roto Pit of Pasir coal fetid. The bedding plane was one of the major discontinuities in the Roto Pit and the dip of which is about $60^{\circ}$in the northern part and $83^{\circ}$in the southern part. The dip of bedding becomes steeper from north to south. The plane and toppling failures are presented in many slopes. In laboratory test the average uniaxial compressive strength of mudstone was 9 MPa and that of weak sandstone was 10 MPa. In-situ test showed that the rocks of Roto north mining area are mostly weak enough to be classified in grade from R2(weak) to R3(medium strong weak) and the coal is classified in grades from R1(Very weak) to R2(Weak). The detailed stability analysis were carried out on 4 areas of Roto north(east, west, south and north), and 2 areas of Roto south(east and west). In this paper, the minimum factor of safety was set to 1.2 which is a general criterion for open pit mines. Using the stereographic projection analysis and the limit equilibrium method, slope angles were calculated as 30~$36^{\circ}$for a factor of safety greater than 1.2. Then these results were re-evaluated by numerical analysis using FLAC. The final slope angles were determined by rational described abode. A final slope of 34 degrees can guarantee the stability for the eastern part of the Roto north area, 33 degrees for the western part, 35 degrees for the northern part and 35 degrees for the southern part. For the Roto south area, 36 degrees was suggested for both sides of the pit. Once the pit slope is designed based on the stability analysis and the safety measures. the stability of 니ope should be checked periodically during the mining operations. Because the slope face will be exposed long time to the rain fall, a study such aspreventive measures against weathering and erosion is highly recommended to be implemented.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.430-440
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• 2000

A series of studies such as geological logging data analysis, detailed geological survey, rock mass evaluation, in-situ and laboratory tests, rock strength and mechanical properties of the rock were concerned. The stability of the slope were carried out inorder to design the pit slope and individual benches using the stereographic projection analysis and numerical methods in Roto Pit of Pasir coal field. The bedding plane was one of the major discontinuities in the Roto Pit and the dip of which is about 60$^{\circ}$ in the northern part and 83$^{\circ}$ in the southern part. The dip of bedding becomes steeper from north to south. The plane and toppling failures are presented in many slopes. In laboratory test the average uniaxial compressive strength of mudstone was 9MPa and that of weak sandstone was 10MPa. In-situ test showed that the rocks of Roto north mining area are mostly weak enough to be classified in grade from R2(weak) to R3(medium strong weak) and the coal is classified in grades from R1(Very weak) to R2(Weak). The detailed stability analysis were carried out on 4 areas of Roto north (east, west, south and north), and 2 areas of Roto south(east and west). In this paper, the minimum factor of safety was set to 1.2 which is a general criterion for open pit mines. Using the stereographic projection analysis and the limit equilibrium method, slope angles were calculated as 30∼36$^{\circ}$ for a factor of safety greater than 1.2. Then these results were re-evaluated by numerical analysis using FLAC. The final slope angles were determined by rational described above. A final slope of 34 degrees can guarantee the stability for the eastern part of the Roto north area, 33 degrees for the western part, 35 degrees for the northern part and 35 degrees for the southern part. For the Roto south area, 36 degrees was suggested for both sides of the pit. Once the pit slope is designed based on the stability analysis and the safety measures, the stability of slope should be checked periodically during the mining operations. Because the slope face will be exposed long time to the rain fall, a study such aspreventive measures against weathering and erosion is highly recommended to be implemented.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.224-255
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• 2022

This study was carried out to examine the changes in vascular flora in the first and second surveys targeting 32 outstanding forest wetlands in Jeonnam area including Gwangju metropolitan city, and based on this, establish a future monitoring system and effectively manage the excellent forest wetlands. The survey investigated the area seasonally every 4-5 years from 2015 to 2021. The change of flora of 32 excellent forest wetlands in Jeollanam-do increased from 103 families, 311 genera, 496 species, 16 subspecies, 38 varieties, 6 varieties, 556 taxa, to 111 families, 362 genera, 599 species, 16 subspecies, 51 varieties, 8 varieties, 674 taxa. Remarkable plants such as Red list and plants endemic to the Korean Peninsula increased also. However, Nepeta cataria and the like are exterminated locally, so an in situ and ex situ conservation strategy must be established. In the case of plants categorized according to wetland preference, the distribution ratio of such wetland plants slightly decreased and the distribution ratio of such terrestrial plants lightly increased for absolute wetland plants. It is necessary to prepare countermeasures for the terrestrialization of forest wetlands and to develop research techniques that can distinguish boundaries. In addition, the forest wetland should be systematically managed and supervised by designating it as a Forest Genetic Resources Reserve that can effectively conserve it.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.1
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• pp.40-49
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• 2004

An ecological study on a sea urchin population, Strongylocentrotus nudus, a key role species in recovery of macroalgal bed, was conducted in Hosan, Samcheok area on the east coast of Korea. Three experimental plots, namely, AMB (artificially-restored macroalgal bed), BG (barren grounds) and NMB (natural macroalgal bed) were established after a pilot survey in June 2002. Distribution and abundance, grazing rates, predation pressure and predator guilds on S. nudus were estimated in three plots bimonthly from Aug. to Dec., 2002. Abundance of S. nudus was lowest, but median test diameter of the urchin was highest (Kruskal-Wallis test, p-value, p<0.001 in Aug. and p=0.003 in Oct.) in NMB In-situ grazing rate of S. nudus estimated by enclosure cage experiment in NMB was about 12 times higher in Aug. (160.0 mg seaweed/g sea urchin/day) than in Oct. (13.8). Predation intensity measured by tethering experiment was higher in NMB. Most of the predators on S. nudus were invertebrates and no fish predators were found. Predator guilds identified by the fish trap experiment using live or dead sea urchins included who]ks Neptunea arthritica, starfish Asterina pectinifera, hermit crabs Pagurus of. samuelis, Paguristes barbatus, brown shawl crabs Atergatis integerrimus and crabs Actaea subglobosa. High predation pressure on S. nudus in natural macroalgal beds was the likely cause of its low density. Elevated sea urchin density and the consequent lasting deforestation of macroalgae in barren grounds demonstrate the importance of predation pressure on sea urchins.

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.371-388
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• 2023

A stratum with a complex composition and a distributed low-permeability soil layer is difficult to remediate quickly because the soil remediation does not proceed easily. For efficient purification, the permeability should be improved and the soil remediation agent (H₂O₂) should be injected into the contaminated section to make sufficient contact with the TPH (Total petroleum hydrocarbons). This study analyzed a method for crack formation and effective delivery of the soil remediation agent based on pneumatic fracturing, plasma blasting, and vacuum suction (the PPV method) and compared its improvement effect relative to chemical oxidation. A demonstration test confirmed the effective delivery of the soil remediation agent to a site contaminated with TPH. The injection amount and injection time were monitored to calculate the delivery characteristics and the range of influence, and electrical resistivity surveying qualitatively confirmed changes in the underground environment. Permeability tests also evaluated and compared the permeability changes for each method. The amount of soil remediation agent injected was increased by about 4.74 to 7.48 times in the experimental group (PPV method) compared with the control group (chemical oxidation); the PPV method allowed injection rates per unit time (L/min) about 5.00 to 7.54 times quicker than the control method. Electrical resistivity measurements assessed that in the PPV method, the diffusion of H₂O₂2 and other fluids to the surface soil layer reduced the low resistivity change ratio: the horizontal change ratio between the injection well and the extraction well decreased the resistivity by about 1.12 to 2.38 times. Quantitative evaluation of hydraulic conductivity at the end of the test found that the control group had 21.1% of the original hydraulic conductivity and the experimental group retained 81.3% of the initial value, close to the initial permeability coefficient. Calculated radii of influence based on the survey results showed that the results of the PPV method were improved by 220% on average compared with those of the control group.

• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.162-176
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• 2005

This study was carried out as a field survey and a review of articles to investigate a characteristic of the distribution pattern in Korean endemic Corylopsis coreana. Distribution of Corylopsis coreana was found in Boseung-gun, Gwangyang-si, Suncheon-si, Jeumam-myeon Goheung-gun, Ganjeon-myeon Gurye-gun, Mt, Cheongwan Jangheung-gun, Nogodan Mt. Jiri in Jeollanam-do, Mt. Cheonhwang Namwon-si and Beamsagol and Banyabong Mt. Jiri in Jeollabuk-do, Sancheong-gun, hadong-gun and Namhea-gun in Gyeongsangnam-do and Mt. Backun, Pocheon-si in Gyeonggi-do. Total flora in the distribution region of Coryloplsis coreana was recorded as 242 taxa; 70 families, 159 genus, 216 species, 22 varieties, 4 forma. Ratio of taxonomic categories was consisted of Pteridophyte $5.8\%$, Gymnosperm $3.7\%$, Dicotyledon $18.6\%$ and Monocotyledon $71.9\%$. Ratio of Life cycle styles was Annual $1.7\%$ and Perennial $93.3\%$. Ratio of growth habit was appeared to Herb $44.2\%$, Vine $12.4\%$, Shrub $17.8\%$ and Tree $25.6\%$. The distribution region of Corylopsis coreana found to typical type which distribute in N, NE or NW slope. The native Corylopsis coreana of Sinjeonri Sungju-eup in Jellanam-do appeared to have a declining tendency which was caused by influence of tree lager.

• Geophysics and Geophysical Exploration
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• v.20 no.3
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• pp.137-145
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• 2017

High-grade limestone applied to various chemical industries is abundant within upper Pungchon formation in Taebaeksan basin, South Korea. Geophysical exploration is one of the most efficient methods to investigate subsurface geological structure in an extensive area. Since the geophysical exploration for the high-grade limestone has rarely been conducted in Korea, its appropriate strategy has not been set up yet. In this study, we focused on to suggest the reasonable strategy and accumulate geophysical databases which are essential for interpreting geophysical images by characterizing laboratory physical properties of in-situ rocks. Hence, rocks were obtained from drilled cores consisting of lower Hwajeol formation, Pungchon formation, and dykes in Jeongseon area, Gangwon province. Geophysical laboratory experiments and petrography of the rocks were conducted. Since susceptibility values of the rocks in Pungchon Formation were obviously lower than those of upper Hwajeol and dykes, it is considered that the lithological boundaries could be distinguished by magnetic survey. In addition, electrical properties of the rocks in middle Pungchon formation were relatively different compared with those of upper/lower Pungchon formations. Thus, induced polarization is shown to be able to detect the high-grade limestone in upper Pungchon formation.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2005.04a
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• pp.85-101
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• 2005

This study was carried out a field survey and review articles to investigate a characteristic of the distribution pattern in Korean endemic Corylopsis coreana. Distribution of Corylopsis coreana was found from Boseung-gun, Gwangyang-si, Suncheon- si, Jeumanl-myeon Goheung-gun, Ganjeon-myeon Gurye-gun, Mt. Cheongwan Jangheung-gun, Nogodan Mt. Jiri in Jeollanam-do, Mt. Cheonhwang Namwon-si and Beamsagol and Banyabong Mt. Jiri, in Jeollabuk-do, Sancheong-gun, hadong-gun and Namhea-gun in Gyeongsangnam-do and Mt. Backun, Pocheon-si in Gyeonggi-do. Total flora in the distribution region of Coryloplsis coreana were recorded as 242 taxa; 70 families, 159 genus, 216 species, 22 varieties, 4 forma. Ratio of taxonomic categories was consisted of Pteridophyte $5.8\%$, Gymnosperm $3.7\%$, Dicotyledon $18.6\%$ and Monocotyledon $71.9\%$. Ratio of Life cycle styles was Annual $1.7\%$ and Perennial $98.3\%$. Ratio of growth habit was appeared to Herb $44.2\%$, Vine $12.4\%$, Shrub $17.8\%$ and Tree $25.6\%$. The distribution region of Corylopsis coreana found to typical type which distribute in N, NE or NE slope. The native Corylopsis coreana of Sinjeonri Sungju-eup in Jellanam-do appeared to a declining tendency which caused by influence of tree lager.

• Journal of The Geomorphological Association of Korea
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• v.19 no.4
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• pp.59-71
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• 2012

This research was carried out to analyze long-term shoreline change on Busan Songjeong Beach using multi-temporal remote sensed data, GPS survey data and grain size analysis. As a result of multi-temporal satellite imagery analysis, the beach was stable status till early 2000s, but the erosion occurred over whole beach after the construction of shore protection road since 2000. In the result of DEM analysis, the elevation of beach reduced and the slope of berm increased after construction of shore protection road along the coast, this means the erosion environment was dominant on the beach. But the sedimentation was slightly stronger than the erosion in northern region of the beach, then the slope of berm was gentle. In the result of grain size analysis using in-situ samples, the coarsening-trend was found in southeastern region (Line E) of the beach, it is caused by strong wave energy from the outer sea. Consequently, major causes of the beach erosion in the study area were the interception of sand supply from a dune owing to shore protection road construction and scouring phenomenon by strong wave energy in southeastern region of the beach. If the topographic or artificial change will not occur in the future, the erosion in this area will continue. Therefore the prevention measures are required.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.187-192
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• 2015

In general, design of urban intersections are fundamentally different from rural intersections, but current urban intersection design has been appled to rural standards. This study has suggested the design standard for urban intersection grades based on the existing literature, field investigating and comparative analysis. Moreover, this study analyzes and compares the differences between urban and rural intersections, and intersections have been derived by appropriate design standards after reviewing the domestic and international grades design criteria. Site survey was performed to validate the derived design criteria by analyzing statistically to establish the design standards. Results were produced for the intersection portion grade standards by comparing the number of instructions which produced appropriate slope degree from 2.5% to 3% in normal condition and slope can be extended to 5% in some critical cases. In-situ investigation was performed to validate the produced data where slope was found from 0.0~8.6%. Additional data of accident analysis were also collected for the validation of the suggested data and correlation analysis was performed using the SPSS tool. Data were analyzed statistically using 95% significance level for vehicle-to-vehicle collided, head-on collision accident rates, where accident rates significantly correlated with the grade. Therefore, appropriate grade at the intersection should be designed and applied in order to reduce the number of accidents at the intersection. Finally, appropriate grades for urban intersections are suggested from 1-3% for normal cases and grades could extend up to 5% for unavoidable cases where extra care must be taken when designing.