• Steel and Composite Structures
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• v.51 no.1
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• pp.93-101
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• 2024

This paper presents an experimental and analytical study on a steel slit damper designed as an energy dissipative device for earthquake protection of structures considering soil-structure interaction. The steel slit damper is made of a steel plate with a number of slits cut out of it. The slit damper has an advantage as a seismic energy dissipation device in that the stiffness and the yield force of the damper can be easily controlled by changing the number and size of the vertical strips. Cyclic loading tests of the slit damper are carried out to verify its energy dissipation capability, and an analytical model is developed validated based on the test results. The seismic performance of a case study building is then assessed using nonlinear dynamic analysis with and without soil-structure interaction. The soil-structure system turns out to show larger seismic responses and thus seismic retrofit is required to satisfy a predefined performance limit state. The developed slit dampers are employed as a seismic energy dissipation device for retrofitting the case study structure taking into account the soil-structure interaction. The seismic performance evaluation of the model structure shows that the device works stably and dissipates significant amount of seismic energy during earthquake excitations, and is effective in lowering the seismic response of structures standing on soft soil.

• Journal of Korea Soil Environment Society
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• v.3 no.3
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• pp.87-92
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• 1998

The effect of chemically oxidized intermediates of Polynuclear Aromatic Hydrocarbon (PAH) compounds on the degradation of the parent PAHs was characterized and evaluated for the context of cooxidation. Anthracene and pyrene exhibited extensive degradation (mean percent removal of 57.5%) after 28 days of incubation by introducing the Fenton oxidation intermediate of the PAH compounds, while unoxidized anthracene and pyrene exhibited 12.5% removal The chemical oxidation products can serve as a structually similar analogue substrates for a consortia of soil microorganisms and as a metabolic intermediates in the biodegradation sequence of the parent PAH compounds. These results may be interpreted in the context of cooxidation mechanism whereby high recalcitrant PAH compounds are biodegraded in the soil and suggest a potential tool for bioremediation of PAHs contaminated soils and protection of groundwater.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.177-184
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• 2000

Geotube is a tube made of geotextile and hydraulically filled with dredged soil. This technological method has been widely used in the advanced countries of the world to build the shore protection embankment. The dredged contaminated sediments from the lake, river, and harbor can be pumped into the geotube by using the hydraulic pump. So, environments effects can be minimized and enhanced by using this method. This paper presents a field test result of a geotube in the land reclamation project for the Songdo New City construction site. The dredged silty clay was dredged by the dredging ship and hydraulically pumped into the geotube. The height of geotube was measured at every filling stage and also measured width and diameter of geotube with the elapsed time. The unit weight of soil and undrained shear strength of filled soil in a tube were measured at the various locations and heights of geotube with the elapsed time. Geotube technique can be effectively implemented for the silty clayey soil with using the dredging ship.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.06a
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• pp.53-60
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• 1998

The effect of chemically oxidized intermediated of PAH compounds on the degradation of the parent PAHs was characterized and evaluated for the context of cooxidation. Anthracene and pyrene exhibited extensive degradation (mean percent removal of 57.5%) after 28 days of incubation by introducing the Fenton oxidation intermediate of the PAH compounds, while unoxidized anthracene and pyrene exhibited 12.5% removal. Dehydrogenase activities for the oxidized PAH studies ware enhanced two to five folds to the unoxidized PAHs studies. The chemical oxidation products can serve as a structually very similar analogue substrates for a consortia of soil microorganisms and as a metabolic intermediates in the biodegradation sequence of the parent PAH compounds. These results may be interpreted in the context of cooxidation mechanism whereby high recalcitrant PAH compounds are biodegraded in the soil and suggest a potential tool for bioremediation of PAHs contaminated soils and protection of groundwater.

• Current Research on Agriculture and Life Sciences
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• v.23
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• pp.53-60
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• 2005

This study was carried out in order to produce useful material for the forest multiple use and forest protection management by soil physio-chemical analysis of studied area in Mt. Namsan. The result of soil physio-chemical analysis and statical analysis represented as following. In side of physical properties of forest soil in Mt. Namsan, Soil depth was average 31.4cm and available soil depth was average 20.0cm. Soil type was Brown forest soil that representative soil type in Korea. Soil texture was sandy loom(SL) except valley area. In side of chemical properties, the range of soil acidity was 4.29 ~ 5.19 (average 4.76), organic matter content was 3.17% that compared the lowest value to organic matter content of Korea forest soil. Available phosphorus was 3.64ppm that was lower than others forest soil. Exchangeable cation content was similar to the Korea brown forest soil. Cation exchange capacity(CEC) was $8.22cmol_c/kg$ in Mt. Narnsan.

• Journal of the Korean GEO-environmental Society
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• v.3 no.4
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• pp.59-66
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• 2002

Designs for rockfall protection systems must consider rock and soil types, the angle of the slope, conditions on top and the toe of the affected area. Rockfall protection fence is installed to block for falling rock from cut slopes and this is one of the most common rockfall protection measures. The capability of the fence is provided that sum of capability of poly vinyl chloride coated wire mesh, steel support and wire rope respectively. But in some case, the rockfall protection fence was not supported rockfall energy less than total capability of the fence through the full scale rockfall tests. Therefore, the objectives of this paper are to indicate the problems of fence capability and to improve the design specifications for the fence.

• Corrosion Science and Technology
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• v.16 no.6
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• pp.294-297
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• 2017

For the longer service life of steel pile, cathodic protection is selected sometimes at corrosive environment. The cathodic protection design improvement was investigated in this study. The current demand for cathodic protection was calculated from the potentiostatic current monitoring of the steel specimen in the deaerated soil samples. In this study, the current distribution was studied using the Boundary Element Method (BEM) and the Finite Element Method (FEM) numerical analysis methods. The optimum layout of the anode was developed and confirmed by numerical analysis. Under the conventional design of the anode, the length of the anode hole is same as the pile length. We found that, at the bottom end of the pile, the current density is too high. When the anode hole length was 80% of the pile length, the current consumption at the end was reduced. The construction cost of anode hole drilling was decreased about 20%, as compared to the conventional design. Furthermore, the life of the anode materials could be extended by reducing the current consumption at the end section. Using this approach, the construction cost was reduced significantly without any under-protection area on the steel piles.

• Korean Journal of Microbiology
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• v.6 no.4
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• pp.131-140
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• 1968

The soil of the reclaimed tidal land, located in Chogi-ri, Is. Kanghwa, Korea was used in this experiment. The experimented soil samples were collected from 18 sites with its time elapsed after the shore-protection works, soil-depth and the vegetation of saline plants, and at each site samplings were conducted monthly from March through October, 1968, for the purposes of examining the changes of microbial populations for the microbes such as bacteria, actinomycetes and fungi, by using the dilution plate method. The numbers of the microbes in these soils generally showed lower levels comparing with those of other soils. The more time elapsed after the reclamation, the higher numbers of the microbes inhibited the soils. Higher populations were there in the surface soils than in the lower part of the area. The surface soils included comparatively better conditions in aeration and contents of organic matter than in the lower part, and this fact was. same as in general soils. However, not so was this in the case of March, April and October due to the higher soil temperatures in the lows. At the experimental sites where the halophytes such as Salicorniu were grown vigourously, the more densly the plants grew, the higher populations of actinomycetes and fungi were, but not in the case of bacterial population. This means, in this soil with dense Salicornia, it is difficult to obtain good-natured soils in short time without a higher population of bacteria. For the rapid utilization of the land soil, in this view of point, the methods increasing the number of bacteria in the soil are needed as well as the cultivation and harvesting Salicorniu which indicated in the privious paper(Hong, et al., 1969a). According to the results of this experiment, the changes of soil-microbial populations in the reclaimed tidal land soil containing high salinity depend deeply upon the interrelations of many environmental factors such as soil-salinity, soil-components and contents, concentration of organic matters, pH, aeration, and air and soil temperatures, as in the general soils.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.39-47
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• 2002

This study was carried out in order to produce useful material for the forest multiple use and forest protection by soil physico-chemical analysis of studied area in Mt. Palgong. The results of soil physico-chemical analysis and statistical analysis represented as following 2 points. 1. Soil depth was in the range of average 61.1 cm and soil texture was loamy sand and sandy loam except Donghwasa area. The part of solid phase and gaseous phase were higher than other areas, but liquid phase was less in verse. Soil water content was in an average 49.5%, penetrability was average $1.95{\times}E^{-2}cm/sec$ and the average of soil hardness was $1.64Kg/cm^2$. This data showed that soil water content, penetrability and soil hardness were good at Mt. Palgong forest soils. 2. Soil pH was the range of 3.4 to 6.0, organic carbon content was 2.8% that is nearly mean of the Korea brown forest soils, total N content is somewhat smaller than that of other places, and total average C/N ratios was 13.9. Average available $P_2O_5$ concentration was 5.05 mg/kg that is lower than that of any others. The concentration of available P of coniferous forests is higher than that of deciduous forests. Exchangeable cations content is similar to those of the Korea brown forest soil and the order of the cation content extent is $Ca^{2+}$ > $Mg^{2+}$ > $Na^+$ > $K^+$.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.804-812
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• 2011

To prevent the overflow of various harmful chemicals, it is necessary to modify the chemical management system with an expansion to institutionally regulated substances. This modification should be preceded by selection of the priority chemicals, with a diverse chemical ranking system (CRS) applied to select the chemicals in developed countries. In Korea, a systematic CRS was used in a project related to soil and groundwater, however, it is inadequate to compare soil and groundwater CRS to that of surfacewater. In this study, a priority chemical ranking system for surfacewater was proposed through the analysis of international and domestic CRS cases. This was then applied to 161 chemicals to derive the priority list of harmful chemicals. As a result, Chemical RAnking of surFacewater polluTants (CRAFT) is presented for the protection of human health and the aquatic ecosystem from surfacewater pollutants. The components of CRAFT are the human health toxicity, aquatic ecosystem toxicity and reliability assessment factors. Three lists were derived from the 161 priority harmful chemicals for the protection of human health, aquatic ecosystem or both. It is expected that this result can be useful to prioritize harmful chemicals for the protection of human health and the aquatic ecosystem from Korean surfacewater.