• Environmental Analysis Health and Toxicology
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• v.16 no.3
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• pp.121-126
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• 2001

Analytical method of benzophenone (BP) in sediment and soil was developed by gas chromatography/mass selective detector/selected ion monitoring (GC/MSD/SIM). The ultrasonic extraction of US EPA (method 3550B) method and liquid-liquid extraction for sediment and soil samples were used for the analysis of BP from sediment and soil. BP was extracted with n-hexane. Organic layer was washed with 5% sodium chloride solution. 1∼2 l of the concentrated solution of organic layer was applied to GC/MSD. The retention time of BP peak was 11.10 min. Recovery (％) of BP by ultrasonication from sediment and soil samples was 96.0∼100.6％ and 40.0∼83.0％, respectively. Recovery of BP by liquid-liquid extraction was 51∼59％ in soil samples. The detection limit of BP in sediment and soil samples were determined to 0.1 ng/g.

• Analytical Science and Technology
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• v.28 no.5
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• pp.317-322
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• 2015

Simultaneous analytical method has developed for the determination of anion biocides in soil by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chlorite and chlorate in soil were extracted with pure water, and cyanuric acid and sodium dodecylbenzenesulfonate (Na-DBS) were extracted with mobile phase (0.25 mM ammonium formate in 20 mM formic acid : acetonitrile (1:1)). The extract was injected into the LC-MS/MS system after filtration. The method detection limits in this study were 0.04 mg/kg for chlorite, 0.04 mg/kg for chlorate, 0.27 mg/kg for cyanuric acid, and 0.05 mg/kg for Na-DBS, respectively. The method was applied to the analysis of 50 soil samples collected from 40 sites sprayed with biocides and 10 background sites. As a result, anion biocides were not detected in all sites.

• Analytical Science and Technology
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• v.22 no.4
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• pp.293-301
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• 2009

As a basic research for development of the domestic field-portable XRF spectrometer, we discussed the analytical results of bench-top ED-XRF and field-portable XRF method for polluted heavy metals such as Cr, As, Se, Hg, Pb, Cd in soil samples. To obtain the best performance of the XRF spectrometer, the instrumental parameters of X-ray tube-voltage and measurement time were optimized for 6 heavy-metal elements in soil using certified reference material. The quantitative analysis of Cr, As, Se, Hg, Pb, Cd concentration in certified reference materials and soil samples were compared by empirical method and fundamental parameter method.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1009-1019
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• 2009

Soil nailing method is widely used in reinforcing slopes and excavating earth. The analysis of nail-reinforced slopes, in order to determine the economical length ratio and nail angle, complicated analytical need to be applied by means of computer programs. Therefor this suggested Soil stability Chart for nailed slopes which may be very useful for pre-design, rapidly design, and final check. Three slope types, three nail length and three nail angles are selected for the stability analysis by using limit equilibrium method of Bishop and French Method. From the above results, this study propose the slope reinforced design charts for dry season and rainy season. This proposed reinforced design charts can check dry season as well as rainy season, also these charts can provide reinforcing requirement, soil nail's economical length ratio and nail angle as well.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.37-47
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• 2004

In this study the load distribution and settlement of soil nailed-drilled shafts subjected to axial loads were evaluated by a load-transfer approach. Special attention was given to the reinforcing effects of soil nails placed from the shafts to surrounding weathered- and soft-rocks based on an analytical study and a numerical analysis. An analytical method that takes into account the number, the positions on the shaft, the grade, and the inclination angle at which the soil nails are placed was developed using a load transfer curve methods. Through the comparative study, it is found that the prediction by present approach simulates well the general trends observed by the in-situ measurements and numerical results SHAFT 4.0. It is also found that the reinforcing effects of soil nails increases in the order of hard-, soft- and weathered-rock since the ultimate shaft resistance far large bored piles in weathered rocks is fully mobilized after small displacements of the shaft, compared to the soft- and hard-rocks and subsequently the side resistance is transferred down to the soil nails.

• Computers and Concrete
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• v.22 no.2
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• pp.221-225
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• 2018

In this paper, vibration analysis of concrete foundations resting on soil medium is studied. The soil medium is simulated by Winkler model considering spring element. The concrete foundation is modeled by thick plate elements based on classical plate theory (CPT). Utilizing energy method consists of potential energy, kinetic energy and external works in conjunction with Hamilton's principle, the motion equations are derived. Assuming the simply supported boundary condition for the concrete foundation, the Navier method is used for calculating the frequency of the structure. The effect of different parameters such as soil medium, mode numbers, length to width ratio and length to thickness ratio of the concrete foundation are shown on the frequency of the structure. At the first, the results are validated with other published works in order to show the accuracy of the obtained results. The results show that considering the soil medium, the frequency of the structure increases significantly.

• Geomechanics and Engineering
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• v.38 no.3
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• pp.261-273
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• 2024

This study presents a groundbreaking analytical approach to find an exact solution for the bearing capacity of strip footings on reinforced slopes, utilizing the two-phase approach and slip line method. The two-phase approach is considered as a generalized homogenization technique. The slip line method is leveraged to derive the stress field as a lower bound solution and the velocity field as an upper bound solution, thereby facilitating the attainment of an exact solution. The key finding points out the variation of the bearing capacity factor N_γ with influencing factors including the backfill soil friction angle, the footing setback distance from the slope crest edge, slope angle, strength, and volumetric fraction of inclusion layers. The results are evaluated by comparing them with those of relevant studies in the literature considering analytical and experimental studies. Through the application of the two-phase approach, it becomes feasible to determine the tensile loads mobilized along the inclusion layers associated with the failure zone. It is attempted to demonstrate the results by utilizing non-dimensional graphs to clearly illustrate variable impacts on reinforced soil stability. This research contributes significantly to advancing geotechnical engineering practices, specifically in the realm of static design considerations for reinforced soil structures.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.3-8
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• 2000

A simple and rapid simultaneous analysis method of BTEX and TPH in soil was developed. 5g of soil sample were mixed with sodium sulfate and then extracted with 10 mL of mixture of acetone and dichloromethane (1:1). Extraction was performed for 10 min in sonicator and analysis was with GC-FID. The detection limits of BTEX and TPH was 0.8 and 10 mg/kg, respectively. The analytical recoveries were >90% for all BTEX and TPH. Low boiling point fuels and high boiling point fuels are consistently reproduced within RSD 7%. The analysis results show very simple and rapid quantitation of BTEX and TPH in soil sample with low RSD.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.258-268
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• 2014

The test method of aerobic transformation in soil has established based on international test guideline (OECD TG 307). And then, the case study was conducted with [$^{14}C$]butachlor. Butachlor is commonly used herbicide in Korea. [$^{14}C$]Butachlor was treatrd $6.83mgKg^{-1}$ in loamy soil. The treated soil was incubated in flow-through system for 60 days. The mass balance of applied radioactivity (AR) ranged from 91.1 to 95.5% and from 93.0% to 97.7% for non-sterile and sterile soils, respectively. In non-sterile soil, the concentration of [$^{14}C$]butachlor was declined from 94.4% AR at 0 day to 8.4% AR at 60 days after treatment. 2-Chloro-2',6'-diethylacetanilide was the major degradation product detected in soil extract. The calculated $DT_{50}$ and $DT_{90}$ of butachlor were 10.4 days and 34.6 days, respectively. $^{14}CO_2$ and non-extractable soil residue were increased up to 3.5% and 43.5% AR at 60 DAT. There is no significant decrease of the [$^{14}C$]butachlor through the incubation period in sterile soil.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.108-119
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• 2001

The Spectral Analysis of surface Waves(SASW) Method has a great has a great potential for rapid determination of shear wave velocity profile of ground. However, it has an inherent limitation in the interpretation of test results due to the assumption that the ground is layered horizontally. The reason of the assumption is that difficulties exist in obtaining analytical solutions of wave equation when a soil system is composed of inclined soil layer. In this study, a finite-element method has been employed to assess the effects of dip angle and stiffness contrast of inclined soil layers and the testing direction on the dispersion curve. The propagation of wave front in the inclined soil layer was also investigated. The results indicated that the influence of dip angle on the dispersion curve is getting obvious as the dip angle increases and the propagation of wave front in the inclined layer also entirely different compared with the case of the horizontal layer.