• Journal of the Korean Geotechnical Society
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• v.22 no.3
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• pp.13-21
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• 2006

Geosynthetic damage has attracted a major attention since the introduction of geotextiles for civil engineering applications. In this study 3 pilot trial embankments were carried out to investigate the behaviours of reinforced embankments over soft cohesive soils and to find the optimum methodology of embankments over soft soils. As the seamed part of polyester mat (PET, tensile strength 15 ton) used in the first full-scale field test was ruptured under progressing rotational slope failure because of unexpectedly rapid construction of embankments, the excessive pore water pressures were measured. On the soil behavior where tension explosion of mat was continued, pore pressure larger than the one caused by embankment height was measured. Especially, at the depth of 5.0 m under the ground pore pressure increased over long term. It was discussed with respect to the height of embankment and heaving behavior of soft soils.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.319-324
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• 1994

Bond test was carried out to assess the effect of several variables on bond characteristics between reinforcing bar and concrete. Key variables are concrete compressive strength(low, medium high, and ultra-high), bar diameter(13mm and 22mm), and concrete cover(25mm; 1-inch, 38mm; 1.5-inch, and 51mm; 2-inch). Confining effect and bar spacing are not taken into account. Thirty-two specimens subjected to uniaxial tension were tested under hypothesis uniform bond stress distribution along the reinforcing bar embeded in concrete. Test results(ultimate bond stress) were compared with bond and development provisions of the ACI building Code(ACl 318-89) and local bond stress versus slip relationship diagram represented to show effect of the above variables.

• Resources Recycling
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• v.8 no.4
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• pp.11-19
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• 1999

Fly ash generated from (he pulverized coal power plant have caused the serious ocean pollution due to the disposal in the ash pond, the life reduction of a power plant and the waste of re-utilizable resource The research to reuse the unburned carbon and mineral composing of the ash has been progressed. In this study. the physical and chemical characteristics of high grade ash and unburned carbon particles obtained from countercurrent column flotation are investigated. The cleaned ash of the less 0,5% loss on Ignition(LOI) in carbon content is a spherical sphere and 39.8${\mu}m$ in size of MMD(Mass Median Diameter). 2.22 $m^2/g$ of specific area. The morphology of high LOI carbon particles is a amorphousness, 76.6 ${\mu}m$ of particle size and 15.2 $m^2/g$ of specific The high grade cleaned ash and the high LOI ash have some difference in the light of physical. chemical and morphological characteristics

• Geotechnical Engineering
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• v.9 no.3
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• pp.49-60
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• 1993

The compatibility of chemicals in the leachates with the three natural and artificially -made liner materials is analyzed by performing the laboratory hydraulic conductivity test. The selected liner materials are natural marine clay, fly ash and weathered granitic soil stomped from Kimpo Wastefills, Seochon power plant and Mansu Dong, Inchon, respectivaly. Bentonites of 20 and 10 percent by weight are used as additive materials for fly ash and weathered granitic soil and the chemical solutions used in the test are acetic acid, methanol, heptane, and aniline which are frequently found in the leachate of waste fills. The concentrations of the chemical solutions are 100% and 75%. The results of the tests show that hydraulic conductivities of the oxter materials are increased by one or two orders of magnitude with permeating pure chemical solutions. The rate of hydraulic conductivity increase is lowest for Seochon fly ash admixed liner and highest for natural marine clay liner. The influence of hydraulic chemical solutions on the liner materials is least for acetic acid and largest for aniline. The increases of conductivity are not shown with the permeation of the solution of concentration 75%. At least by this test results, it can be recognized that the tested liner material can be quite stable with the solutions of significantly high concentration except pure solutions.

• Journal of the Korean GEO-environmental Society
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• v.22 no.3
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• pp.5-13
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• 2021

Due to population growth and industrial development, the amount of industrial waste is increasing every year. In particular, in a thermal power plant using finely divided coal, a large amount of coal ash is generated after combustion of the coal. Among them, fly ash is recycled as a raw material for cement production and concrete admixture, but about 20% is not utilized and is landfilled. Due to the continuous reclamation of such a large amount of coal ash, it is required to find a correct treatment and recycling plan for the coal ash due to problems of saturation of the landfill site and environmental damage such as soil and water pollution. In recent years, the use of a fluid embankment material that can exhibit an appropriate strength without requiring a compaction operation is increasing. The fluid embankment material is a stable treated soil formed by mixing solidifying materials such as water and cement with soil, which is the main material, and has high fluidity before hardening, so compaction work is not required. In addition, after hardening, it is used for backfilling or filling in places where compaction is difficult because higher strength and earth pressure reduction effect can be obtained compared to general soil. In this study, the possibility of use of fluidized soil using high water content cohesive soil and coal ash is considered. And it is intended to examine the flow characteristics, strength, and bearing capacity characteristics of the material, and to investigate the effect of reducing the earth pressure when applied to an underground burial.

• Economic and Environmental Geology
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• v.42 no.3
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• pp.235-246
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• 2009

High-saline ground water, whose eclectrical conductivity value ranges from 12,000 to 21,000 $\mu$S/cm, occurs at the small catchment of Gilsan stream near Geum-river estuary dike. These high-saline ground water comes form three different aquifers consisting of two horizons of sand sediments and one weathered zone with top part of unconformity. For these three aquifers showing mutual independence in terms of hydrogeological and hydrogeochemical connection, we examined characteristics of aqifer occurrences and their water chemistry, and observed and analyzed the fluctuations of the ground water level and electrical conductivity. Our study results indicate that the high-saline characteristics of ground water in this study area should not come from dynamic recent seawater intrusion, but might be due to the fossil saline water included and isolated within the paleo-sediments or weathered zone and their upper unconformity part. This high-saline water seems to be now partially mixed and affected by freshwater in the higher inland reach of Gilsan stream.

• Journal of the Korean GEO-environmental Society
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• v.12 no.5
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• pp.29-36
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• 2011

In this study, settling experiment was performed about cohesive and sandy soils among representative sample expected to dredge and dump for analysis of settling and consolidation characteristic. The analysis showed the definite difference between cohesive soils and sandy soils of relationships with settling and consolidation coefficient, a water content, interfacial heights. But directly after a dredged reclamation, prediction results about a initial volume change showed that cohesive soil of a water content change was decreased rapidly as time goes by, but sandy soils made no difference in a water content change. Results were compared and analyzed with the settling and consolidation coefficient and a initial settling velocity by real soil amounts for a feasibility check about test conditions applied to these experiment: we judge that test conditions are appropriate, each material by such these analyses suggests the scope of settling and consolidation coefficient, average and the representative relational formula.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.89-98
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• 2009

In this research, settling tests with marine clays in Korea and extensive literature review were performed to investigate the characteristics of sedimentation and consolidation so that their behaviors during dredging and reclamating could be evaluated. Design parameters related to Yano's method (1985), one of experimental approaches having been used widely in Korea to estimate sedimentation and consolidation, were analyzed and their proprieties were reassessed. For samples from four different sites of south and west coasts in Korea respectively, settling tests with 1m height of columns were carried out, changing initial water content and height of sample in order to evaluate settling and consolidation characteristics of them from analyzing test results. More reliable regression curves than values from literature review were obtained as analyzing test results of estimating coefficient of sedimentation/ consolidation and initial setting velocity with changing initial water content. Relation between height of soil solid and surface height of slurry at the stages of initiation and termination of consolidation was also assessed. Finally, for marine clays of south and west coasts of Korea, ranges and average values of these design parameters were evaluated and typical empirical equations between these design parameters were also proposed. On the other hand, comparisons of characteristics of sedimentation and consolidation between marine clays from south coast and them from west coast were also performed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.783-794
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• 1994

Recently, several failure cases of concrete structures during construction have been reported. The main reason for these failures is attributed to the poor quality of concrete during construction. It is, therefore. necessary to develop and use high quality concrete. The purpose of the present study is to explore the characteristics of superplasticized concrete, especially the effects of mineral admixtures on the fluidity and strength characteristics of high performance concrete. The mineral admixtures considered in the present study are fly ash, blast furnace slag and silica fume, respectively. The major test variables include the amount of these mineral admixtures, cement contents and water-cement ratios. The compressive strengths for various cases were measured and reported. Optimum contents of mineral admixtures for strength development were derived. The corrosion phenomena of reinforcements embedded in various concrete specimens have been also studied. The present study provides useful basis to apply high-performance concrete to actual structures.

• Journal of the Society of Disaster Information
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• v.14 no.2
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• pp.141-153
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• 2018

Purpose : The subject site selected in this study was a place that was prepared through the reclamation of foreshore completed in 1973. Since then, the site has been occupied by the industry of ship repair for over 30 years. Method : The results of a precise soil examination conducted in 2013 showed that the site was seriously contaminated with TPH over an area of $10,000m^2$ and GL(-)3.0m in depth, with an expanding coverage of contamination. Results : The soil contamination by refined petroleum products often results in adverse effects to human health and ecological systems, thus the contamination should be purified as soon as possible. Conclusion : Hydrogeological investigation can be employed to assess the groundwater movement and propagation of contamination to determine the potential agents or contaminants in the soil contaminated with high concentration TPH.