• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.4
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• pp.35-41
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• 2005

In order to analyse the flow problems for an unsaturated soil, it is required to examine closely the characteristics of the coefficient of permeability which is changing with the matric suction. To this ends, a permeability test was conducted on the three samples;granular soil, cohesive soil and silty soil. The specimen was made by pressing the static pressure on the mold filled with soil and the void ratio was controled with the different compaction ratio. And the test was performed by using the modified apparatus of the steady state method which was proposed by flute (1972). The range of matric suction was 0-90 kPa. The measured results for the coefficients of permeability were analysed with the void ratio and the compaction ratio, and it was examined closely the characteristics of the permeability for an unsaturated soil.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1012-1017
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• 2010

Sewer Pipes are not being managed for twenty years after laying. So, The life span of sewer pipes is on the decrease. For solve the life span decrease of sewer pipes, correct checking of questions and measure preparation are necessary through investigation in sewer pipes. This research investigated on the state of sewer pipes in the housing and industrial sites through CCTV(closed-circuit television) and device of digitalized strain investigation. And, a result is as follows. A results of PE, PVC, GRP, CSP investigations were found of pipe-transformation state by earth pressure and external load.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.132-144
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• 2001

Iln order to figure out criteria of bentonite for using as impervious material of waste landfill, laboratory experiments were performed to reveal the geotechnical properties of soil-bentonite mixtures such as compaction test, direct shear test, unconfined compression test, triaxial compression test, consolidation test and permeability test. The results of the study are summarized as follows ; 1. Based on the compaction test, optimum moisture content increased with the increase of bentonite content, but maximum dry density decreased. 2. In unconfined compression test, the maximum strength of the soil-bentonite mixtures appeared at 10% bentonite content. The correlation equation between stress($\sigma$) and strain($\varepsilon$) of the soil-bentonite mixtures is given by ; $\sigma=\frac{a\cdot\varepsilon}{\varepsilon^n+b}$ 3. In shear test of the mixtures. the shear strength showed an increasing trend with increase of bentonite content and the maximum shear strength appeared at 10% bentonite content. 4. In consolidation test, the coefficient of compressibility $(a_v)$$(m_v)$$(C_v)$

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1623-1629
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• 2008

The purpose of this research is to assess the application of recycled-aggregate that is gained from construction wastes as the material of compaction pile method. At the same time, the development of the new technique rectifies defects of the existing compaction pile method for soft ground improvement. In this research, model tests were conducted for analyzing the effect of the soft ground improvement by porous concrete pile using recycled aggregate. Through the results of the model tests, the behavior of settlement on composition ground with surcharge pressure were elucidated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.2
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• pp.51-64
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• 1991

To evaluate the compaction - induced lateral earth pressure acting on retaining structures such as retaining walls, abutments, culverts, underground walls, etc., a new equation is developed using the newly proposed hysteretic model simulating soil's loading - unloading behavoir under Ko-condition. The lateral pressurds calculated by the new equation are found to agree well with those of field tests previously performed by other researchers.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.192-197
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• 2004

The anisotropy in coefficient of thermal expansion (CTE) between the in-plane and out-of-plane of 3-dimensional thick composite structures induces residual stresses and the large void content due to insufficient compaction of fabric composites, which results in low interlaminar strengths. In order to reduce the through thickness CTE and the void content, in this work, carbon fabric phenolic laminates were compacted by pressure generated by autoclave and a compressive jig, from which the through-thickness CTEs and the void contents were measured. From the measurement, it was found that the through-thickness CTE and the void content had different characteristics from ordinary composites due to gas produced during the cure reaction of phenolic resin.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.411-412
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• 2006

A high nitrogen PM tool steel has shown to have an excellent galling resistance due to the introduction of a high amount of a low friction phase predominantly consisting of VN. Tool making and heat treatment are according to standard procedures. An increase of tool life of more than two times compared to ordinary tool steels is found. Furthermore, the new low friction tool steel shows a potential for sintered parts with higher densities through the applica bility of increased compaction pressure or minimized lubricant amount.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.998-1003
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• 2011

This investigation was performed to determine the hydraulic conductivity coefficient and water holding capacity for a specified compaction forces which are the amount of mechanical energy applied to the porous granule (PG) volume. Most current specifications of minerals and perlite as growth media require to be compacted to a specified density, which in general is equivalent to a certain percentage of laboratory compaction. The water holding capacity of the saturated PG was very large at potential above -1 bar compared with perlite, but very little water remained below this value. The water holding capacity and hydraulic conductivity characteristics of graded PG amended with the ground coir less than 2 mm in diameter were also determined from pressure outflow data. The saturated hydraulic conductivity of the saturated and compacted PG was slightly lower by more than one tenth order of magnitude at equal matric potentials of perlite, but when expressed on the basis of equal water deficits, the conductivity of PG was higher at all but the smallest deficits than those of perlite.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.4
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• pp.292-297
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• 1989

To achieve fiber/resin reinforced composites with high quality (void-free, uniform compaction), a basic understanding of the principal factors related to a thermal cycle to cure the matrix and a pressure to compact the system is necessary. In this paper, some dielectric and mechanical properties of glass cloth reinforced epoxy composites are measured as a function of fabrication conditions, where the time that the pressure is applied to the sample during the cure process is controlled. Both the tensile strength and frequency characteristics of the sample are improved significantly when the pressure is applied at the start point of gelling.