• The Journal of the Petrological Society of Korea
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• v.18 no.4
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• pp.279-291
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• 2009

Radon is a natural radionuclide originated from radioactive decay of radium in rocks and soil. It is colorless, odorless and tasteless elements that mainly distributed as gaseous phase in soil pore space. The present study analyzed the characteristics of long-term radon variation in granitic residual soil at Mt. Guemjeong in Guemjeong-gu, Busan and determined the effects of atmospheric temperature, rainfall and soil temperature and moisture. Periodic measurements of radon concentrations in soil gas were conducted by applying two types of in-situ monitoring methods (chamber system and tubing system). Radon concentration in soil gas was highest in summer and lowest in winter. The variations in soil temperature and atmospheric temperature were most effective factors in the long-term radon variations and showed positive co-relations. The air circulation between soil air and atmosphere by the temperature difference between soil and atmosphere was analyzed a major cause of the variation. However, other factors such as atmospheric pressure, rainfall and soil moisture were analyzed relatively less effective.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.232-235
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• 1998

Air sparging system is a kind of in-situ bioremediation method in the contaminated ground water. When Air sparging, the both of water circulation and oxygen transfer happend in the same time. The hydraulic differential head is zero at the middle height of well, is negative below the height and is possitive above the height. Hydroraulic head gradient is proportioned to air superficial velocity in the well. But over 24m/min of the superficial velocity, the hydraulic head gradient increase little.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.199-202
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• 2004

In this study the field-scale tests were performed in which in-situ E/K remediation technologies were applied, and then the results were present. For traditional E/K remediation method the efficiency of remediation is not large, but the enhanced method with citric acid significantly increases the removal efficiency. Also EDTA, reported as a good enhancement agent for removal of heavy metals, is similar to that of citric acid. Therefore citric acid is preferred rather than EDTA in view of the cost on the contaminant removal per unit concentration.

• Journal of Environmental Science International
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• v.28 no.8
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• pp.655-667
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• 2019

This research aims to identify the possibility of developing A horizon resources that can be used for construction and civil engineering work. As such, the utility of A horizon resources was examined by establishing planting ground through a mixture of soil layers and by analyzing the growth and development of Pinus densiflora. The physicochemical and physical properties of the soil were as follows: the A horizon was sandy clay loam, B horizon was sandy loam, and the mixture of two layers appeared as sandy loam, which was identical to the B horizon. The experimental groups did not show any significant difference in their physical properties of porosity and degree of water-stable aggregates. With regards to chemical properties, the A horizon as well as the mixture of A and B horizon showed acidity while the B horizon showed alkalinity. The figures of organic matter, total nitrogen, available phosphate, and replaceable potassium were greater as the A horizon content increased, whereas the figures of replaceable calcium, replaceable magnesium, and conductivity increased as the A horizon content decreased. As a result of the growth and development of Pinus densiflora in each planting ground, the final survival rates were all above 100%. However, the tree height and the rate of growth for the diameter of root were higher in the order of A horizon > A horizon + B horizon > B horizon,indicating that the increased A horizon content is related to the growth and development of Pinus densiflora. The treatment of soil with improvement agents, used to recover the functions of in-situ soil showing poor growth and development, did not have a clear impact on the soil texture and porosity. However, the degree of water-stable aggregates increased significantly when using O horizon as the soil improvement agent among the types of in-situ soil. In contrast, all items related to the chemical properties showed significant differences following the treatment by soil improvement agents. The survival rate according to the treatment of soil improvement agents for the growth and development of Pinus densiflora was higher in the order of organic horizon = no treatment > compound fertilizer > organic fertilizer + compound fertilizer > organic fertilizer; this result was statistically significant with a marginal significance value of the log-rank test(p < 0.05).

• Geomechanics and Engineering
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• v.12 no.3
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• pp.505-522
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• 2017

A fundamental study of drilled shafts-soil systems subjected to lateral cyclic loading in weathered soil was conducted using numerical analyses. The emphasis was on quantifying the soil resistance of laterally cyclic loaded pile using 3D finite element analysis. The appropriate parametric studies needed for verifying the cyclic p-y characteristic are presented in this paper. A framework for determining the cyclic lateral load transfer curve (p-y curves) on the basis of numerical analyses is proposed. Through comparisons with results of field load tests, the three-dimensional numerical methodology in the present study is in good agreement with the general trend observed by in situ measurements and thus, represents a realistic soil-pile interaction for laterally loaded piles in soil than that of existing p-y method. It can be said that a rigorous present analysis can overcome the limitations of existing cyclic p-y methods to some extent by considering the effect of realistic three-dimensional combination of pile-soil forces. The proposed cyclic p-y curve is shown to be capable of predicting the behavior of the drilled shafts in weathered soil.

• Korean Journal of Soil Science and Fertilizer
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• v.13 no.1
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• pp.1-6
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• 1980

The infiltration rates of the upland soils on hill side slope were investigated in situ using rainulator of which rainfall intensity was 100mm/hr. The soil moisture profile after the water infiltration was compared with that calculated from Youngs' equation. The results obtained are as follows: 1. Time required for infiltration rate to reach constant during rainfall was 15 to 25 min. The infiltration rate measured after 30 min was considered to be final infiltration rate. 2. The final infiltration rates of clay soils were lower than 10mm/hr., loamy soils 10 to 20., coarse loamy soils 20 to 30, and sandy soils higher than 30mm/hr., respectively. 3. The saturated hydraulic conductivity of the surface soil of Samgag sandy loam was 0.47mm/min., Songjeong clay loam0.16 mm/min., and Jeonnam silty clay loam 0.14mn/min., respectively. 4. The soil moisture profile calculated from Young's equation was in close agreement with measured in situ.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.505-508
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• 2015

Soil bulk density is a key parameter for soil physical property. Much root placed in rhizosphere soil lump, especially in grassland and orchard, makes it difficult to measure soil bulk density. This experiment was carried out to countermeasure the above drawbacks. Volume check apparatus using water-filling method was made of acryl for higher accuracy in bulk density measurement. 10 types of land cover, including bare, tall fescue, rye, and soybean, were used for determining the relationships between root and bulk density. In this study, higher root volume resulted in higher differences in bulk density between in-situ core soil and root-ridded core soil, which indicated the volume check apparatus through water-filling could be useful for increasing the accuracy of bulk density of soils with much root.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.99-107
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• 1997

In this study, a series of batch-scale tests were conducted to optimize the design parameters for the application of soil washing techniques to the hydrophobic organic compounds(HOCs)-contaminated soil and to find the effective methods for the recovery of surfactants from washing effluent by using solvent. Several nonionic surfactants (polyoxyethylene oleyl ester) and sophorolipid were applied to the artificially contaminated soil (4,000 mg n-dodecane/kg dry soil). The effects of washing time, concentration of surfactant solution, dilution ratio, and temperature on washing efficiencies were examined. Hydrophile-liphophile balance (HLB) number was proven to be one of the important parameters for soil washing. The HLB numbers of OA-5 and sophorolipid are too low to form a stable soil-water emulsion. They showed very low washing efficiencies less than 10e1o. If HLB number is in the proper range to form a stable soil-water emulsion, surfactant having higher solubility for HOCs shows higher washing efficiency. OA-14 having higher HLB number than OA-9 formed more stable soil-water emulsion. But its washing efficiency was about 20% due to a lower molar solubility ratio (MSR) than OA-9. OA-9, which forms a stable soil-water emulsion and has comparatively high sotubility for HOCs, showed about 60% washing efficiency by itself. To recover anthracene effectively from OA-9 washing effluent by using benzene as an organic solvent, desirable temperature and pH were $30^{\circ}C$ and 2, respectively.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.4 s.31
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• pp.13-19
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• 2004

It has been a common practice to use manually processed soil maps in planning of land readjustment. This study is intended to develop a geographic information system for computerized processing of soil maps. The pilot region of land readjustment for this study was set at a mountain area with diverse formation of soil. Cadastral maps were employed for the basis map, and the main map was prepared using the information obtained from in-situ soil survey and laboratory tests. The detailed soil maps were drawn using the geographic information system, and analyzed and compared with manually processed maps. The soil maps, in conjunction with a computer program of land readjustment design, can be applied in estimation of soil works appropriate for the given soil condition, and also in selecting the efficient construction equipments.

• Proceedings of the Korean Geotechical Society Conference
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• 1994.06c
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• pp.137-149
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• 1994

This paper was focused on the basic theory of soil nailing method in advance, and reviewed of design and construction process in-situ application case. It also analyzed the result of field measurements and construction.