• Journal of Environmental Science International
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• v.4 no.4
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• pp.379-386
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• 1995

Permethrin [3-phenox yben zyl(1RS)-cis,tans-3-(2,2-dichloroviny1)-2,2- dimethylcyclopropane carboxylate] insecticides were selected to study adsorption and leaching potentials related to pollution on Commerce silty clay loam soil near Baton Rouge, Louisiana, USA. GLC-ECD chromatogram of permethrin included 32.5 % of cis-pemehin and 67.4 % of trans-permethrin. Extraction efficiencies of is and trmu-pemetun were 92.5 % and 92.3 % in fortified water, respectively and 85.9 % and 88.8 % in fortified soil, respectively. At a 1:10 moi]/water ratio,the Koc values for sis and fan isomers of permethrin were 938 and 877, respectively. Leaching of permethrin was evaluated in soil columns$(5.4 cm i.d. \times 26 cm length)$. Total recoveries of the permethrin applied to the soil column were $84.5\pm3.1%$. When the soil columns were leached with three pore volumes of water, the distributions of cis-permethrin leached were 6.10 % and 0.07 % of amount applied in the untreated zone soil and leachate water, respectively Trans-pemethrin distributions were 5.20 % in the untreated zone soil and 0.05 % in leachate water. Cis and trans-pemethrin was strongly adsorbed to soil. The results of the study showed the strong relationship between adsorption and leaching. Cis and trans-permethrin to be leached into the groundwater in soils with shallow aquifers were suggested a low leaching potential.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.454-459
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• 2009

In order to identify the effect of soil salinity on saturated hydraulic conductivity in reclaimed paddy soils, we established the soil columns uniformly packed with soils collected at every 20 cm up to 60 cm from the reclaimed paddy area with high and low salinity which has been cultivated rice plants for the last 30 years. The soil textures were sandy loam and loamy sand for high-salinity and low-salinity topsoils, respectively. For high-salinity and low-salinity soils the ECes were ranged from 25.2 to $37.8dS\;m^{-1}$ and 3.0 to $3.4dS\;m^{-1}$ while the ESPs were ranged from 7.70 to 20.84 % and from 5.12 to 11.33 %, respectively. The bulk densities of the soil columns were adjusted to $1.15{\pm}0.03g\;cm^{-3}$. The results of the soil column experiments shows that the stabilized saturated hydraulic conductivity of low-salinity soil was $0.62cm\;hr^{-1}$ at the topsoil while there were little water flow at the bottom of the soil columns packed with high-salinity soils. After removal of $Na^+$ ions with $1N\;NH_4OAc$ from the high-salinity soil, Ksat of the saline soil was drastically increased to $0.23cm\;hr^{-1}$. Soil columns of high-salinity topsoil treated with four different concentration of NaCl influent after removal of soluble and exchangeable cations with $1N\;NH_4OAc$ show Ksat in the range of $0.1{\sim}0.15cm\;hr^{-1}$ and the Ksat slightly decreased as the concentration of NaCl influent was increasing. Conclusively, we could assume that $Na^+$ can be significantly contributed to the saturated hydraulic conductivity in newly reclaimed sandy soil.

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.464-471
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• 1996

Trifluralin was selected to study the leaching potentials related to the pollution on Commerce silty clay loam soil near Baton Rouge, Louisiana, USA. The batch equilibrium of trifluralin resulted in the Koc value of 875. When the soil columns(5.4 cm i.d. ${\times}$ 26 cm length) were leached with three pore volumes of water, the distributions of trifluralin in soil and leachate were 99.993% and 0.007% of the total recoveries, respectively. When applied at the rate of 1,683 g/ha in the field, the amount of trifluralin within the $0{\sim}10$ cm soil depth was 96.9% of that within the $0{\sim}60cm$ soil depth 31 days after application. The concentrations of trifluralin detected in 1- and 2m- depth wells during 62 days after application ranged from 0.04 ng/mL to 0.08 ng/mL, which were lower than 2.0 ng/mL of the U.S. EPA advisory levels for drinking water. Trifluralin was strongly adsorbed on soil and hardly reached ground water. The leaching properties of trifluralin in the fields were predicted and concurred with those in the columns.

• Journal of the Korean Geotechnical Society
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• v.24 no.9
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• pp.13-21
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• 2008

Partitioning tracer method is a useful tool to characterize large domains of the aquifers contaminated with light nonaqueous phase liquids (LNAPLs). Sorption of the partitioning tracers to the organic matter content of soil can potentially influence the efficacy of partitioning tracer method. LNAPL-water partitioning coefficients of tracers ($K_{nw}$), measured by static method, showed linear relationship. Sorption isotherm tests were conducted to evaluate the sorption capacity of the soils packed in the columns and the results were appropriately represented by Freundlich sorption isotherm. The sorption of tracers proportionally increased with the increase of the organic matter content of the soil. Laboratory experiments were conducted in four columns each packed with soils of different organic matter contents to determine the potential interference effects of sorption to soil organic matter content and correction factors for the errors in estimation of LNAPLs by partitioning tracer method. Though there were no contaminants added, breakthrough curves from columns packed with mixture of Jumunjin standard sand and organic matter showed separation of tracers. Columns were then contaminated to residual saturation with kerosene and breakthrough curves were obtained. The results show that sorption of tracers to soil organic matter leads to an increase in the retardation factor (R) and hence, to an overestimation of the saturation of LNAPLs. A relation between the percentage of organic matter content and the corresponding percentage error in the estimation of NAPLs has been developed.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1201-1212
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• 2010

In order to investigate on the effect of stabilization methods for rice paddies contaminated by heavy metals, a series of lab-scale model test was carried out by applying the characteristics of submerged Paddy soil. To perform the lab-scale model test, columns were made by acrylic with the dimension of diameter=10cm, thickness=0.5cm and were filled with soils which was contaminated were mixed with stabilization agents(lime stone 5% and steel refining slag 5% respectively). To manipulate the reduction condition, soils in the columns were submerged with distilled water. And then soil water and subsurface water in each column were sampled in the regular term and analysed the various physical and chemical properties.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.603-608
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• 1998

This study was performed to examine the effect of time dependent properties on RC columns in subway structures subjected to high filled soil layer. By using Program TCC which is a modified version of CPF for the present purpose, a typical column in subway structure was analyzed. Four different model equations for predicted time dependent concrete properties(ACI, CEB-FIP, Bazant & Panula and Korea Bridge Specification) was employed, and the results were compared. It was found that a relevant creep coefficient is recommended to be 1.0 for designing columns in subway structure, and the sol filling work would be performed at least 3 months later after the concrete casting in order to ensure durability by reducing the negative effect of concrete time dependent properties.

• Geomechanics and Engineering
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• v.9 no.4
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• pp.415-426
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• 2015

Researches have been done to discover ways to strengthen peat soil deposits. In this model study, fibrous peat that is the most compressible types of peat has been reinforced with precast peat columns stabilized with ordinary Portland cement and polypropylene fibres. Rowe cell consolidation tests as well as plate load tests (PLTs) were conducted on various types of test samples to evaluate the strength and deformation of untreated peat and peat reinforced by various types of columns. PLTs were conducted in a specially designed and fabricated circular steel test tank. The compression index ($C_c$) and recompression index ($C_r$) of fibrous peat samples reduced considerably upon use of precast columns. Also, PLT results confirmed the results obtained from Rowe cell tests. Use of polypropylene fibres added to cement further decreased ($C_c$) and ($C_r$) and increased load bearing capacity of untreated peat. Finite element method (FEM) using Plaxis 3D was carried out to evaluate the stress distributions along various types of tested samples and also, to compare the deformations obtained from FEM analysis with the actual maximum deformations found from PLTs. FEM results indicate that most of the induced stresses are taken on the upper portion of tested samples and reach their maximum values below the loading plate. Also, a close agreement was found between actual deformation values obtained from PLTs and values resulted from FEM analysis for various types of tested samples.

• Structural Engineering and Mechanics
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• v.31 no.5
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• pp.545-566
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• 2009

Bridge columns are subjected to combined actions of axial force, shear force and bending moment during earthquakes, caused by spatially-complex earthquake motions, features of structural configurations and the interaction between input and response characteristics. Combined actions can have significant effects on the force and deformation capacity of RC columns, resulting in unexpected large deformations and extensive damage that in turn influences the performance of bridges as vital components of transportation systems. This paper evaluates the seismic response of three prototype reinforced concrete bridges using comprehensive numerical models that are capable of simulating the complex soil-structural interaction effects and nonlinear behavior of columns. An analytical approach that can capture the shear-flexural interacting behavior is developed to model the realistic nonlinear behavior of RC columns, including the pinching behavior, strength deterioration and stiffness softening due to combined actions of shear force, axial force and bending moment. Seismic response analyses were conducted on the prototype bridges under suites of ground motions. Response quantities of bridges (e.g., drift, acceleration, section force and section moment etc.) are compared and evaluated to identify the effects of vertical motion, structural characteristics and the shear-flexural interaction on seismic demand of bridges.

• Interaction and multiscale mechanics
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• v.2 no.4
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• pp.397-411
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• 2009

The effect of soil-structure interaction on a simple single storeyed and two bay space frame resting on a pile group embedded in the cohesive soil (clay) with flexible cap is examined in this paper. For this purpose, a more rational approach is resorted to using the three dimensional finite element analysis with realistic assumptions. The members of the superstructure and substructure are descretized using 20 node isoparametric continuum elements while the interface between the soil and pile is modeled using 16 node isoparametric interface elements. Owing to viability in terms of computational resources and memory requirement, the approach of uncoupled analysis is generally preferred to coupled analysis of the system. However, an interactive analysis of the system is presented in this paper where the building frame and pile foundation are considered as a single compatible unit. This study is focused on the interaction between the pile cap and underlying soil. In the parametric study conducted using the coupled analysis, the effect of pile spacing in a pile group and configuration of the pile group is evaluated on the response of superstructure. The responses of the superstructure considered include the displacement at top of the frame and moments in the superstructure columns. The effect of soil-structure interaction is found to be quite significant for the type of foundation used in the study. The percentage variation in the values of displacement obtained using the coupled and uncoupled analysis is found in the range of 4-17 and that for the moment in the range of 3-10. A reasonable agreement is observed in the results obtained using either approach.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.201-205
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• 1998

Leakage of hydrocarbon compound from underground storage tank has been a significant issue to the hazard of environmental contaminants. It is therefore necessary to develop the measurement technique of hydrocarbon compound concentration. In this study, the possibility of TDR application to measure concentration of hydrocarbon compound, especially diesel, in a sandy soil was investigated. Experiments were conducted in two different conditions. The first one was to measure the resistances of the soil columns packed according to the various ratios of tab water and diesel content in the total voids. The other was to measure the resistance of the soil under the flow condition where diesel oil was allowed to infiltrate into the KCl-saturated soil column. The experimental results showed that there exists a significant relationship between oil% and TDR-measured resistance. This suggests that TDR can be an effective device to measure the concentration of hydrocarbon compound in a soil.