• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.172-175
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• 2003

Field scale application of in-situ ozonation were carried out for remediation of variably saturated soils contaminated with diesel fuel with 3 dimensional test cell (3m$\times$2m$\times$2m). After 20 days of ozone injection, more than 90% of removal rate was observed through the 3-D test cell. This result might be caused by uniform distribution, relatively low oxidant demand, and low water content of soils, as well as high oxidation potential of ozone. However, less than 50 % of injected ozone was monitored through the 3-D test cell even after 20 days of injection.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.314-317
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• 2003

Plants may enhance the remediation of munitions at contaminated soils using various natural processes. A computer model can be used as a valuable tool for assisting phytoremediation by predicting the transport and fate of target contaminants at remediation sites. For this research, modeling of phytoremediation and bioremediation of soil contaminated with 2, 4, 6-trinitrotoluene (TNT) was studied. Indian mallow (Abutilion avicennae) was grown in columns packed with 126mg TNT/kg contaminated soils for 50 days and a simulation model was developed to simulate the transport and fate of TNT and its breakdown products interacting with plant roots in a partially saturated soil. The column test showed the substantially enhanced reduction of TNT and greater soil microbial activity in Indian mallow planted soil compared to unplanted soil. The model successfully simulated the fate of TNT and by-products in phytoremediation. The results suggested that plants could provide favorable environments for reduction of TNT.

• Advances in environmental research
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• v.5 no.4
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• pp.263-282
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• 2016

Contaminant transport in groundwater induces major threat and harmful effect on the environment; hence, the fate of the contaminant migration in groundwater is seeking a lot of attention. In this paper a two dimensional numerical flow and transport model through saturated layered soil is developed. Groundwater flow and solute transport has been simulated numerically using proposed model. The model implements the finite volume time splitting method to discretize the main equations. The performance, accuracy and efficiency of the out coming numerical models have been successfully examined by two test cases. The verification test cases consist of two-dimensional, groundwater flow and solute transport. The final purpose of this paper is to discuss and compare the shape of contaminant plume in homogeneous and heterogeneous media with different soil properties and control of solute transport using a zone for minimizing the potential of groundwater contamination; furthermore, this model leads to select the effective and optimum remedial strategies for cleaning the contaminated aquifers.

• Geotechnical Engineering
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• v.9 no.3
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• pp.5-22
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• 1993

A series of laboratory tests (physical and mechanical index and engineering design) were conducted on undisturbed granite soils of CW and RS weathering grades in Korea. From these testes it can be concluded that most of physical and mechanical index values are very sensitive to change in weathering grade from CW to RS. Engineering design tests indicate that the unconfined compressive strength and the shear strength parameters are significantly reduced and that the soil becomes ductile and plastic with increasing weathering and saturation. It was found that weathered granite soils have the special characteristics when water saturated: (i) they significantly lose their shear strength(especially cohesion) and unconfined compressive strength, (ii) they are fragile and their grains break down in water as observed in grain size analysis.

• Geomechanics and Engineering
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• v.11 no.6
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• pp.771-785
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• 2016

The thermal conductivity of soils is an important property in energy-related geotechnical structures, such as underground heat pumps and underground electric power cable tunnels. This study explores the effects of geotechnical engineering properties on the thermal conductivity of soils. The thermal conductivities of quartz sands and Korean weathered silty sands were documented via a series of laboratory experiments, and its variations with effective stress, porosity, and water saturation were examined. While thermal conductivity was found to increase with an increase in the effective stress and water saturation and with a decrease in porosity, replacing air by water in pores the most predominantly enhanced the thermal conductivity by almost one order of magnitude. In addition, we have suggested an improved model for thermal conductivity prediction, based on water saturation, dry thermal conductivity, saturated thermal conductivity, and a fitting parameter that represents the curvature of the thermal conductivity-water saturation relation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.506-511
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• 1999

Three of the most important factors governing liquid transmission inunsaturated soils are field-saturated hydraulic conductivity, Kfs matric flux potential , ${\Phi}$m and sorptivity, S. The Guelph Permeameter is an in-hole constant-head permeameter, employing the Mariotte Principle. The study was carried out to investiate the characteristics of the water hsed average infiltration coefficient measured by the Guelph Permeameter at the Backokpo watershed in the Han river and at the Bandong watershed in the Keum river.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2C
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• pp.69-77
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• 2012

In general, geothermal energy pile and horizontal ground heat exchangers are installed in shallower depths than conventional vertical ground coupled heat pumps. Consequently their heat exchange performance is strongly governed by thermal conductivity of soil layer. Previous studies have shown that the thermal conductivity of soil above ground water table significantly affects the heat exchange rate because of partially saturated condition in soil and consequent variation of soil thermal conductivity. This paper presents a study result on the prediction of thermal conductivity of weathered granite soils. For weathered granite soils sampled from 5 locations, thermal conductivity tests were conducted with varying porosity and degree of saturation. The existing thermal conductivity models in literatures appeared inappropriate to the weathered granite soils. Hence, an empirical equation was proposed in this paper and its validity was examined by applying it to thermal conductivity test results obtained for weathered granite soils in this study and from literatures.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.5
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• pp.31-39
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• 2007

This study was carried out to evaluation the recycled waste soils from construction site for planting soil. For this purpose, the concentrations of polluted materials and the physico-chemical properties were measured at recycled soil samples of an industrial waste treating company in the Metropolitan landfill area. The concentrations of polluted materials did not exceed to the standard critical levels of soil pollution in all analyzed items. The measures of the samples soil texture (loamy sand), bulk density (1.09~1.32g/$cm^3$), saturated hydraulic conductivity ($1.6{\times}10^{-3}{\sim}1.8{\times}10^{-3}$cm/sec), solid phase distribution (0.4~0.5$m^3/m^3$), porosity (0.5~0.6$m^3/m^3$), Ex. $K^+$ (1.0~1.2cmol/kg), Ex. $Mg^{2+}$ (0.2~0.6cmol/kg) were identified as not worse than those of conventional planting soil. But the sample soils have serious problems for planting soil such as high levels of pH (9.6~11.5), EC (0.78~1.84ds/m) and Ex. $Ca^{2+}$ (25.6~34.5cmol/kg), low level of organic matter (0.2~0.3%). It is required to improve pH, EC and Ex. $Ca^{2+}$ of sample soils. Consequently, the results suggested a high potential of recycling of the wastes soils for planting soil.

• Geotechnical Engineering
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• v.12 no.2
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• pp.107-114
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• 1996

A series of shear tests is performed to measure friction coefficients of the interface between different reinforcements and weathered granite soils. The reinforcements tested are smooth steel strip, Paraweb(friction tie) and geotextile with rough surface, while the weathered granite soils are composed of different, grain size distribution. Soils are compacted with the energy of 95% modified AASHTO and fully saturated before testing to simulate the worst site condition. Because of characteristics of the direct shear apparatus, shear strength is obtained in terms of drained condition. Test results show that the more fines the soils contain, the larger ratio of friction coefficient ($\mu=\frac{tan{\delta}}{tan{\Psi}}$) is obtained. Also the ratios are much higher for the Friction tie and the geotextile compared to the smooth steel strip. Those suggest that even weathered granite soils with 36% fines are possible to use as backfill of reinforced earth structures for the two reinforcements when a drainage system is provided.

• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.45-51
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• 2012

The shear strength of weathered granite soils under unsaturated condition was evaluated by $K_0$ consolidated triaxial tests. Various matric suctions in the unsaturated triaxial tests were applied using suction-controlled triaxial test apparatus for weathered granite soils obtained in Daegu. Soil water characteristic curve (SWCC) laboratory tests for drying and wetting procedure were performed and van Genuchten curves were fitted by experimental results. The contribution of matric suction in unsaturated soils is directly correlated to effective stress and evaluated from SWCCs. The effective stresses were estimated from these SWCCs and the relationship between effective stress and unsaturated shear strength was determined. In the effective stress description, the unsaturated shear strength with respect to various suctions indicates unique relationship and almost the same as that of the saturated envelope.