• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1296-1305
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• 2008

In this study, the spatial distribution of depth between alluvial soil and weathered soil of Song-do new city is analyzed using geostatistics. From analysis results, the boundary depth of north-east region is deeper than that of south-west region, and average depth of north-east region is 27.14m and average depth of south-west region is 23.25m. The boundary depth is estimated by ordinary kriging and inverse distance method, and estimated results are almost similarity. So, in Song-do new city, these two method can be used to estimate the boundary depth. The ordinary kriging method is a very useful tool because the more exact analysis of spatial continuity and distribution characteristic is possible.

• Geomechanics and Engineering
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• v.32 no.1
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• pp.1-20
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• 2023

To predict the consolidation behavior of dredged and reclaimed marine clays exhibiting consolidation settlement with large strains, the finite strain consolidation theory must be used. However, challenges in appropriately applying the theory and determining input parameters make design and analysis studies difficult. To address these challenges, design charts for predicting the consolidation settlement of reclaimed marine clays are developed by a numerical approach based on the finite strain consolidation theory. To prepare the design charts, a sensitivity analysis of parameters is performed, and influencing parameters, such as initial void ratio and initial height, as well as the non-linear constitutive void ratio-effective stresspermeability relation, are confirmed. Six representative Korean marine clays obtained from different locations with different liquid limits are used. The design charts for estimating the consolidation times corresponding to various degrees of consolidation are proposed for each of the six representative clays. The consolidation settlements predicted from the design charts are compared to those in previous studies and at an actual construction site and are found to agree well with them. The proposed design charts can therefore be used to solve problems related to the consolidation of reclaimed marine clays having large strains.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.23-25
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• 2013

In this study, the results are compared with the case of the concrete with embedded heating wire to verify the performance of the IB made in order to improve the workability and affordability, and to determine the effectiveness of early frost damage prevention. The IB was made using the 5W heating wire and layed on the upper surface of the concrete. The temperature was reduced to below 0℃ approximately within 24 hours, then approached the external temperature thereafter. On the other hand, when the 20W heating wire was used to make the IB and applied the same way, the temperature remained around -2 to 3℃ on the average even through the temperature was reduced to below 0℃, due to the heating wire with relatively large heating capacity. It appeared to reach 85% of the direct heating by embedding the heating wire relatively deeper in the concrete. However, it was determined that using the IB made with the 20W heating wire will prevent the early frost damage to some degree in -10℃.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.75-77
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• 2013

In this study, the characteristics of temperature history was evaluated for three hot wires with different capacity installed in slab concrete which are relatively thin. Results can be summarized as follows. First, for the case of material using 5W hot wire, all decreased to below zero at or around 24 hours. Similarly, the material using 20W hot wire decreased to 2℃ below zero at or around 80 hours but satisfied the accumulative temperature of 45° D·D at 7 days of material age. On the other hand, the case of 30W hot wire, the biggest capacity, showed the high temperature history of 5℃ in average at all areas except the corners. Thus, the target accumulative temperature was secured at or around the 3 days of material age. Considering the above, the initial damage by freezing can be prevented only if 20W or higher hot wires are used for the slabs at -10℃ of extremely low temperature environment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.334-336
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• 2013

In this study, the temperature history was evaluated for the improved bubble sheets combining hot wires and PE films, which were developed under the extreme environmental condition of -10℃ and applied on the top surface of slab to prevent initial damage by freezing. Results can be summarized as follows. If improved bubble sheets combining hot wires with different capacity on double and quadruple bubble sheets are used, the temperature history for all materials decreased to 2~3℃ below zero but all test materials except Type 1 secured the accumulative temperature of 45° D·D at 7 days of material age, required for the prevention of initial freezing damage. This indicates the bubble sheets can prevent the initial damage by freezing.

• Korean Institute of Interior Design Journal
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• v.24 no.3
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• pp.104-112
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• 2015

This study purposes drawing changing tendency of apartment kitchen areas and character of that by figuring out type, form and per period cause of change of brand apartment kitchen areas. I adopted subject of study as the six leading construction companies considering the apartment rankings of brand and subcontract from 2001 to 2015 when brand apartment was activated(Samsung C&T corporation Raemian, Daelim Industrial Co., Ltd E-pyeonhansesang, Daewoo E&C Prugio, GS E&C XI, Posco E&C The sharp, Hyundai E&C Hillstate) and analyzed kitchen plane of $84m^2{\sim}102m^2$ housing units which were in great demand from apartment housing market. Also, I drew changing trends of kitchen areas by conducting a model house field survey. Through this study result, I will expect the utility of baseline data which is necessary for space development by figuring out kitchen culture, flows and cause of change.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.248-249
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• 2011

전기설비의 경우 설비의 중요성등을 고려하여 수전 LINE과 같이 중요한 설비들은 이중화를 통화여 1 LINE이 고장이 생겨도 잔여회선 또는 잔여 변압기로 무정전으로 전원공급을 할 수 있어야 한다. 그러나, 광양제철소 154KV 전력계통은 고장전류 때문에 345/154KV 주변압기 3대를 분리하여 #1 TR은 S변전소(1계열), #2 TR은 R,J,H,A 변전소(2계열), #3 TR은 D, P 변전소(3계열)의 전력공급을 담당하고 있다. 본 논문에서는 1,2,3계열 분리운전 방안에 대하여 고장전류계산 및 전력 조류계산을 통하여 전력계통구성을 검토하고 개선방안으로써 1,2계열병렬운전, 2,3계열 병렬운전, 1,3계열 병렬운전에 대하여 고장전류 및 전력조류를 수행하여 고장전류 저감방안, 발전기 이설, 부하이설등의 검토를 통하여 병렬운전 가능한 방안을 찾고 궁극적으로 계통안정도에 문제가 없는 범위에서 최적의 개선방안을 찾고자 한다.

• Korean Journal of Metals and Materials
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• v.46 no.10
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• pp.627-633
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• 2008

The austenitic Fe-Mn alloys have received considerable attention as a possible candidate for the automotive structural materials due to their high strength and high formability with high elongation. This research investigates the effect of alloying elements on the phase transformation, deformation behavior and mechanical properties in high Mn steels for the development of a high strength high ductility steel. The mechanical stability of austenitic phases is very important for high ductility and it depends largely on the composition of carbon, manganese and aluminum. The dominant deformation mode shifts from TRIP to TWIP mode as the amount of C, Mn and Al is increased. Especially, even a small amount of Al addition facilitates significantly TWIP deformation due to the increase of stacking fault energy in Fe-Mn alloys, this leads to increase the ductility and also decrease the crack sensitivity.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.47-51
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• 2013

In this study, we carried out an experimental shield TBM excavation model test using a down-scale device in soft clay, to understand tunnel-face stability properties in relation to changes in slurry pressure. We performed five tests according to tunnel depth (0.5D, 0.75D, 1.0D, 1.25D, 1.5D), and compared theoretical tunnel-face pressure with model test results. The range in theoretical tunnel-face slurry pressure ($P_{min}{\leq}P_{slurry\;pressure}{\leq}P_{max}$), which is determined by earth pressure and water level, was very similar to the model test result. This result was due to the more isotropic condition of the soft clay ground, than of rocky ground.

• Journal of the Korea Institute of Building Construction
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• v.12 no.3
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• pp.315-322
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• 2012

The effect of ground granulated blast-furnace slag(GGBS) and alkali activator compressive strength, resistance of chloride attack and freezing-thawing is assessed to develop high volume slag concrete, the replacement rate of GGBS of which is more than 80 percent. result, as the replacement rate of GGBS increases, the compressive strength development properties of concrete in early and long term age decreased and resistance chloride attack and freezing-thawing is increased. The early strength development property, however, is extremely advanced by addition of the alkali activator, which is also found to improve resistance chloride attack and freezing-thawing.