• Journal of the Korean GEO-environmental Society
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• v.13 no.12
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• pp.75-79
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• 2012

In the recycling of industrial waste unlike household waste, the legislation and the governmental systematic support, etc. were not also established due to an anxiety of hazard or harmfulness, etc. and a preconception. So the legislation and the system should be urgently established for the recycling of industrial waste. In this study, the environmental analyzing method of industrial waste-mixed coal ash in ash pond to recycle as a construction material is suggested by considering and analyzing test process and results about environmental impact factors of mixed coal ash. It is certified that there are not environmental problems in the recycling of mixed coal ash in ash pond as a construction material, according as its classification is general waste and each corresponding item of the leaching test result are satisfied with the 'environmental safety criteria' suggested in this study. And to build database, it is necessary to survey the environmental impact on surrounding areas with time after its recycling as a construction material.

• Journal of the Korean GEO-environmental Society
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• v.2 no.2
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• pp.5-12
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• 2001

The physical characteristics and contaminant level of the dredged material generated by the channel maintenance and water quality improvement was analysed in a series of the study of the beneficial uses of dredged material in harbor. Dredged materials were sampled at Kunsan, Kohyun, Samchunpo, and Pohang Harbors and tested in the laboratory(leaching Test). From the experimental results, the specific gravity does not shows large differences, while almost grains are composed of silts and oyster shells except Pohang harbor containing gravels. The COD release rate and ignition loss is high in Kunsan dredged materials because of the watershed pollutants loads. The nutrient release rate is also relatively high. The release concentration of the heavy metals shows the highest values on Zn, Pb, Cd, Cu constituents at Kohyun, Kunsan, Samchunpo, Kunsan, respectively.

• Journal of the Korean GEO-environmental Society
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• v.9 no.5
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• pp.29-36
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• 2008

The shotcrete is a NATM technique as a major tunnel support for ground stability after tunnel excavation. Instead of a general concrete lining method, it is a trend for curtail of construction periods and reduction of construction expenses that required to use of the permanent shotcrete lining. This high-strength shotcrete is required to use as a permanent shotcrete lining. This brought out the solution of environmental pollution and harmfulness to human. Accordingly, in this study specimens for strength measurement were made to develop shotcrete possible to develop materials in early with cement mineral accelerator as NATM method construction. It was compared with existing shotcrete material, unconfined compression test, flexural strength test, antiwashout underwater test were experimented. The fish poison test was experimented to evaluate an influence of environment. As a results of the test, unconfined compressive strength and flexural strength were equivalent with 28-curing day strength of existing material. An antiwashout of research subject material was revealed excellently in antiwashout Underwater test. As a results of the fish poison, an evaluation research subject material was founded more environmentally friendly than existing shotcrete.

• Journal of the Korean GEO-environmental Society
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• v.6 no.4
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• pp.37-46
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• 2005

Waste tires can be used not only for reinforcement material due to its high capacity against tensile force but also effective for massive treatment. In order to use waste tire as reinforcing material Tread mat using tire treads only was made. Plate load tests on the embankment of decomposed granite soil reinforced with Tread mat and geogrids were conducted for comparison with the test results, respectively. And numerical analyses were performed to see the stress and stain around the reinforced material. Tread mat showed bearing capacity increase and the amount was bigger than that of commercial geogrids. Finite element analysis showed decrease of stress beneath the reinforced material and stress distribution. Finally Tread mat was proposed to use for soil reinforcement as a means of massive treatment of discarded tire.

• Journal of the Korean GEO-environmental Society
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• v.13 no.8
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• pp.75-84
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• 2012

In this paper, strength and leaching characteristics of water sludge-added lightweight soils(WALS) considering reinforcing materials(waste fishing net, glue treated waste fishing net and geogrid) and layer(1 or 2 layer) were investigated using unconfined compression test and leaching test. Several specimens of water sludge-added lightweight soil consisted of water sludge, cement, and bottom ash were prepared according to flowability. Reinforcing material added into these specimens were waste fishing net and geogrid. A glue treated waste fishing net was also added in order to increase interlocking between soil mixture and waste fishing net. Strength increased in the order of WALS reinforced by waste fishing net, glue treated waste fishing net, and geogrid. Strength of specimen with double layer-reinforcing material was greater than that of specimen with single layer reinforcing material. Leaching result of WALS was also satisfied with standard of ministry of environment.

• Journal of the Korean GEO-environmental Society
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• v.6 no.1
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• pp.15-21
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• 2005

In this study, the utilization of coal-ash and phosphogypsum was considered as the evapotranspiration final landfill cover(ET cover) material. Cover material considered was the mixture of the weathered granite soil, coal-ash and phosphogypsum and so we sequentially performed the leaching test, column test and field model test to investigate the environmental effects of mixtures of coal-ash and phosphogypsum. In the leaching test, all materials had lower heavy metal concentration than the regulated threshold values. The column test and the review of related regulations were carried out to determine the optimum mixing ratio(OMR) and OMR was soil(4):coal-ash(1): phosphogypsum(1) on the volume base, which was applied to field model test. Field model tests were continued from February to June, 2004 in the soil box that was constructed with cement block. It was verified that coal-ash and phospogypsum mixed with soil was safe environmentally and the mixture of both wastes could improve the water retention capacity of cover materials.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.5-12
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• 2011

Recently, NDS(Natural and Durable Stabilizer)method and other similar methods are composed of inorganic accelerating agent and the ultra-super fine cement have been studied as the ground improvement material in Korea. However, in the existing research, the chemical changing process of NDS in the strength development mechanism with the elapsed curing time and the principles of strength development did not give an explanation. For the popularization of the inorganic grout material, it determined that the mechanism verifying of the curing process had to be clearly preceded. Therefore, unconfined compression test, SEM and XRD analysis were performed by the elapsed curing time and were analyzed. In addition, the same trial for SGR method, that is the representative example of the water glass grout material, was selected as comparative target in order to distinguish properties of NDS more clearly. The result of experiment, the strength development mechanism of NDS could be investigated through the close correlation of the unconfined compression strength - SEM - XRD analysis, and excellence of a performance was confirmed.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.808-812
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• 2010

A great deal of attention is focused on coupled Thermo-Hydro-Mechanical (THM) behavior of multiphase porous media in diverse geo-mechanical and geo-environmental areas. This paper presents general governing equations for coupled THM processes in unsaturated porous media. Coupled partial differential equations are derived from 3 mass balances equations (solid, water, and air), energy balance equation, and force equilibrium equation. Finite element code is developed from the Galerkin formulation and time integration of these governing equations for 4 main variables (displacement $\underline{u}$, gas pressure $P_g$, liquid pressure $P_l$), and temperature T). The code is validated with theoretical solutions for linear material with simple boundary conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.699-704
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• 2010

Tertiary unconsolidated mudstones spread throughout the eastern coast of Pohang area. Recently, the demand for high quality filling materials is increasing due to harbors and large-scale residential land development. But the features of the reclaimed land using soft mudstones have not been made clear yet. Unconsolidated rocks are diversely considered according to a different method of the applied geotechnical investigation. This study is examined that the applicability of mudstone as a harbor reclamation material through the laboratory test and pilot test. Expecially, it must be considered that the environmental characteristics of mudstone as a reclaimed materials.

• Journal of the Korean GEO-environmental Society
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• v.7 no.5
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• pp.67-77
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• 2006

Bearing capacity of soil can be improved by several conventional ground improvement techniques like stabilization and compaction. Recently, the necessity on the reseaches for the bearing capacity of footing reinforced by Geotextile is being significantly increased. In this paper, a series of model tests on sandy ground reinforced by a layer of Geotextile were performed under plane strain condition, and the effects of bearing capacity improvement and behaviour of sandy ground were observed through tests for position and horizontal length, material strength of reinforcement.