• Journal of the Korean GEO-environmental Society
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• v.23 no.4
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• pp.41-48
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• 2022

Jeju island has a special ground layer called 'Sumgol' due to the geological characteristics. The terminology 'Sumgol' is generally defined as the rain fall flows through the Sumgol without blocking and smaller size than cave, which men cannot enter. This paper presents the influence of the Sumgol on ground stability under various loading conditions using numerical simulations when the airport is constructed. The results showed that the vertical settlements of each section are within the allowable settlement.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.04a
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• pp.68-69
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• 1996

• Journal of Naturopathy
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• v.11 no.1
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• pp.18-30
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• 2022

Background: It was to develop an air purification system (APS) using an underground air purification layer to verify the effect of basalt forest's underground air (sumgol) on a volcanic Jeju. Finally, it is necessary to analyze these purified air components and their usefulness to the human body in an air experience center. Purpose: It was to collect basalt forest air, analyze its composition, and explore its effect on the human body. Methods: We APS devices installed at four points in the Papaville area of Jeju. The air discharged from the APS was collected and analyzed the recycling components. An installed experience room filled with negative ions is about 5,000 ions/m³. After allowing the participants to stay for 60 to 120 minutes, we investigated the state of blood vessels. Results: In the analysis of the underground air, the O₂ concentration was 21.18%, which was higher than the average oxygen concentration of 20.94% in the atmosphere. However, Formaldehyde was not detected, and the CO₂ was 419 ppm, which was lower than that of indoor air. The PM2.5 concentration was less than 24 ㎍/m³ and detected anions over 5.000 /m³. The experiencer's vascular states improved, and the increase in pulse rate and stress relief were high. Conclusions: The valuable ingredients identified by analyzing the air were precious for natural healing. The experience results showed that it effectively improved the pulse rate, blood vessels, and stress. These conditions may be highly beneficial as a new area for expanding the basalt lava forest in the Jeju area into the natural healing and wellness industry.

• The Journal of Engineering Geology
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• v.31 no.2
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• pp.199-209
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• 2021

This paper is written to evaluate the ground stability according to the construction of Jeju 2nd airport. Sumgol is the unique characteristics of Jeju soil, which is used to evaluate the ground stability of the airport. The research contents are as follows. 1) The geotechnical characteristics for Jeju 2nd airport was analyzed, and the Sumgol and geotechnical properties were calculated based on the existing geotechnical survey data. 2) The divided sections of Jeju 2nd airport were modeled to evaluate the ground stability after determining the section (runway and airport facilities) which have the different soil and loading properties. 3) The stability and deformation ranges of the airport ground were identified through numerical analysis. The entire airport was divided into three sections to analyze the stability of Jeju 2nd airport, and calculated the stresses, settlements, and strains of each section by computer numerical analysis modeling. For modeling, the ground and load conditions were examined, also pavement conditions for each airport ground section were examined. From the analysis results of each section according to the ground conditions, the vertical settlements were analyzed as 0.11~0.18 m and the sum of effective stress and pore water pressure were 92.75~445 kPa. These results were made by taking into account the Sumgol of the bottom ground without reinforcement, also the soil strength parameters of the airport ground were reduced for computer modeling, Therefore, if proper reinforcements are applied to the ground of Jeju 2nd airport, sufficient airport ground stability can be secured.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.130-135
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• 2002

Water-dispersible colloids are suspected to facilitate transport of contaminants to groundwater. This study evaluated some soil chemical properties in relation to the stability of colloids in soils of Jeju citrus orchards. Thirty surface soil samples were collected, and pH, organic matter content oxalate-extractable Al and Fe contents, and water-dispersible colloid content were measured. In soils of higher pH, water-dispersible colloid contents were higher. The stability of colloids was found to be significantly promoted at pH above 5$\sim$6. Since organic matter can act as a flocculant organic matter content significantly enhanced the colloid stability. In soils of less than 5% organic C, water-dispersible colloid content was expected to be significantly higher. In soils of higher oxalate-extractable Al and Fe contents, colloids remaining in suspension were lower. This indicated that amorphous oxides and hydroxides play important stabilizing roles in soil structure and can stabilize soil clay against dispersion. Therefore in soils of higher pH, lower organic matter, and lower amorphous clay minerals, the stability of water-dispersible colloids and the potential of colloid-mediated transport of organic chemicals to groundwater could be higher.