• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.128-131
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• 2013

Energy losses through windows and doors are big problems in the construction industry. For glass only, it has takes the largest portion of mass from window assembly and it responsible for 24 ~ 45% of energy loss from total building energy loss. Insulating glass unit should maintain their basic functions during their working life in order to contribute positively for global warming issue. There have been many research works for improving insulating glass unit durability. But it is not easy job to fulfill the requirements because insulating glass units composed of many components. So, overall it is required to have right qualify control procedures starting from material selection to fabrication, shipping and installation to the customer site. In this report, we have reviewed the durability of insulating glass unit made from different grades of sealing materials based on globally accepted industry codes such as EN1279. ASTM E 2190 and Locally available code. KS L 2003. The result showed that there is a relationship between the mechanical properties of insulating glass 2nd sealant and the durability of the units.

• Journal of the Korean Geosynthetics Society
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• v.9 no.2
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• pp.41-50
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• 2010

The concrete lining of a tunnel constructed by NATM used to be regarded as facing material which does not support any load from the surrounding ground. But the recent appraisal of the decrepit tunnels revealed that rockbolts and shotcrete deteriorate with time resulting in loss of supporting capability. Consequently, concrete lining has to support part of the load which used to be supported by rockbolts and shotcrete, and thus should be regarded as the final supporting structure in a tunnel. One of the common, and perhaps the most serious problem in concrete lining is the longitudinal cracks taking place at the tunnel crown. The longitudinal cracks, mostly related to the construction procedures, can be developed by many reasons such as the lack of thickness, wrong materials, bad curing environment, and excessive external forces. Many efforts has been made to control and suppress these cracks but efficient and economic way is yet to be found. For efficient crack control in concrete lining, reinforcement by composite fibers, which is the mixture of steel fiber and nylon fiber, is suggested in this study.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.163-174
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• 1999

This paper presents a case history of remedial action adopted for contaminated groundwater in a landfill. The objectives of the projects are : (1) to effectively confine contaminated groundwater with an economically reasonable means, (2) to prevent further contamination of soil by collecting and treat the contaminant. and (3) to assure the environmental safety of the landfill during its operating period. Reported are the process from site investigation, through design and construction of an appropriate remedial action, to the monitoring of the selected confinement system. In view of the results of site investigation, deep soil mixing cutoff wall using the DMW(deep soil mixing cutoff wall) method and specially produced HEC soil stabilizer were used for the construction of deep soil mixing cutoff wall. For rock foundation with sever fractures, chemical grout curtain with urethane was installed. The monitoring results to date indicate that the selected vertical barrier performed satisfactorily.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.107-116
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• 2020

The compaction grouting technique is widely used to improve the liquefaction resistance of loose sands that are liquefaction-prone. Particularly, the horizontal injection of compaction grout is proposed for the liquefiable ground with an overlying structure as it does not allow the vertical compaction grouting. However, there has been limited number of researches on the horizontal compaction grouting. Therefore, this study explores the grout bulb shape and expansion direction in loose sand. A series of scaled two-dimensional experiments on the horizontal compaction grouting was conducted varying the overburden stress. The results show that the grout bulb grows in an elliptical shape though its directivity of major axis changes with the overburden effective stress and relative density. The grout bulb expands faster in a horizontal direction under a low overburden stress with a small relative density. The higher overburden stress and the greater relative density cause the more circular shape with the faster expansion in a vertical direction. The presented finding is expected to contribute to accurate and efficient design of the horizontal compaction grouting method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.61-68
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• 2020

In this study, the international standard ISO TS 16774 Part 3 Test Method for Water (wash out) Resistance and KS F 4935 ｢Sealant Injection type for water leakage maintenance of adhesive flexible rubber asphalt series｣, which are standardized as a quality control method of injection type repair materials used for water leakage cracks in underground concrete structures, are currently used in Korea. As a result, considering the performance criteria of "mass change rate -0.1%" stipulated in KS F 4935, the remaining 13 types repair materials, excluding RG-2 of synthetic rubber and UG-1 of urethane, need to be reviewed for stabilization of the loss resistance due to the flow of ground water. The results of this study are determined to be available as a basic indicator for the selection of repair materials used for cracks in concrete structures. In addition, it is expected that the results of this study can be utilized as reference data that can be reflected in the improvement of the quality of repair materials that will be researched and developed later.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.5
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• pp.387-401
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• 2023

The Earth Pressure Balanced (EPB) Shield Tunnel Boring Machine (TBM) is widely employed for constructing urban underground spaces due to its minimal vibration and low noise levels. The injection of additives offers several advantages, including maintaining shield chamber pressure, reducing shear strength, minimizing cutter wear, and decreasing the permeability of the excavated soil. This technique is known as soil conditioning and involves the application of additives such as foam, polymer, and bentonite slurry. In this study, weathered granite soil commonly encountered at domestic tunnel sites was used as a soil specimen. Foam and polymer were applied as additives to assess the rheological properties of conditioned soils. The workability was evaluated through slump tests, while the rheological properties were assessed through laboratory pressurized vane shear tests conducted under the same conditions. Specially, the polymer was applied under specific conditions with low workability with high slump values, with the aim of evaluating the impact of polymer application. The test results revealed that with an increase in the Foam Injection Ratio (FIR), the slump value also increased, while the torque, peak strength, yield stress, apparent viscosity, and thixotropic area decreased. Conversely, an increase in the Polymer Injection Ratio (PIR) led to results opposite to those of FIR. Additionally, a correlation between the slump value and yield stress was proposed. When comparing conditions with only foam applied to those with both foam and polymer applied, even with similar slump values, the yield stress was found to be lower in the latter conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.272-279
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• 2012

In order to effectively treat livestock wastewater in constructed wetlands by natural purification method, removal velocities of pollutants under different injection methods in constructed wetlands were investigated. The removal velocities of chemical oxygen demand (COD), suspended solid (SS), T-N and T-P by continuous injection method were slightly rapid than those by intermittent injection method in full-scale livestock wastewater treatment plant. The removal velocity (K; $day^{-1}$) of COD by continuous injection method was $0.38\;d^{-1}$ for $1^{st}$ bed, $0.13\;d^{-1}$ for $2^{nd}$ bed, $0.17\;d^{-1}$ for $3^{rd}$ bed, $0.05\;d^{-1}$ for $4^{th}$ bed and $0.17\;d^{-1}$ for $5^{th}$ bed. The removal velocities (K; $day^{-1}$) of COD in $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$ and $5^{th}$ beds by intermittent injection method were $0.210\;d^{-1}$, $0.086\;d^{-1}$, $0.222\;d^{-1}$, $0.053\;d^{-1}$ and $0.137\;d^{-1}$, respectively. The removal velocity (K; $day^{-1}$) of SS by continuous injection method was $0.750\;d^{-1}$ for $1^{st}$ bed, $0.108\;d^{-1}$ for $2^{nd}$ bed, $0.120\;d^{-1}$ for $3^{rd}$ bed, $0.086\;d^{-1}$ for $4^{th}$ bed and $0.292\;d^{-1}$ for $5^{th}$ bed. The removal velocities (K; $day^{-1}$) of SS in $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$ and $5^{th}$ beds by intermittent injection method were $0.485\;d^{-1}$, $0.056\;d^{-1}$, $0.174\;d^{-1}$, $0.081\;d^{-1}$ and $0.227\;d^{-1}$, respectively. The removal velocity (K; $day^{-1}$) of T-N by continuous injection method was $0.361\;d^{-1}$ for $1^{st}$ bed, $0.121\;d^{-1}$ for $2^{nd}$ bed, $109\;d^{-1}$ for $3^{rd}$ bed, $0.047\;d^{-1}$ for $4^{th}$ bed and $0.155\;d^{-1}$ for $5^{th}$ bed. The removal velocities (K; $day^{-1}$) of T-N in $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$ and $5^{th}$ beds by intermittent injection method were $0.235\;d^{-1}$, $0.071\;d^{-1}$, $0.171\;d^{-1}$, $0.058\;d^{-1}$ and $0.126\;d^{-1}$, respectively. The removal velocity (K; $day^{-1}$) of T-P by continuous injection method was $0.803\;d^{-1}$ for $1^{st}$ bed, $0.084\;d^{-1}$ for $2^{nd}$ bed, $0.076\;d^{-1}$ for $3^{rd}$ bed, $0.118\;d^{-1}$ for $4^{th}$ bed and $0.301\;d^{-1}$ for $5^{th}$ bed. The removal velocities (K; $day^{-1}$) of T-P in $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$ and $5^{th}$ beds by intermittent injection method were $0.572\;d^{-1}$, $0.049\;d^{-1}$, $0.090\;d^{-1}$, $0.112\;d^{-1}$ and $0.222\;d^{-1}$, respectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10b
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• pp.31-42
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• 2001

다양한 방식으로 제작된 유리섬유 강화 플라스틱관(FRP pipe)의 인장 및 휨강도 시험 결과로부터 제작방식에 따른 FRP관의 강도 특성을 비교 검토하였다. 또한, 사면보강대책으로서 FRP 그라우팅 공법의 현장 적용성을 평가하기 위하여, FRP 그라우팅에 따른 지반강도의 증진효과 및 보강재의 인발저항력을 산정하였다. 이를 위하여, 지반의 상대밀도 및 구속압에 따른 보강재 인발저항력의 변화 및 압력주입에 의한 확공효과 평가를 위하여 실내모형실험이 이루어졌다. 또한, FRP 그라우팅이 시공된 현장에서 공내재하시험, 투수시험, 그리고 시추공전단시험 등을 실시하여 FRP 그라우팅에 의한 지반보강 효과 및 차수효과를 정량적으로 산정하였다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.291-294
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• 2010

EPS 샌드위치 패널은 화재 시 치명적인 단점을 가지고 있다. 하지만 여전히 EPS 샌드위치 패널이 국내에 많이 사용되는 이유는 가격이나 시공성, 생산성에서 EPS를 대체할만한 물질이 아직 개발되지 않는 실정이다. 글라스 울 패널과 우레탄 폼 패널이 시장에 조금씩 유통되고 있지만 여전히 EPS 패널이 시장에서 70%이상을 차지하고 있다. 그래서 EPS를 코팅, 함침, 주입 등의 여러 가지 방법도 개발되고 있으나 그 중 가장 간단하고 가격이 낮고, 샌드위치패널에 적용이 가능한 코팅법에 의한 난연제의 배합설계와 비드와 난연제의 난연 등급에 따른 최적의 배합비를 제안하고자 한다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.3
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• pp.183-198
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• 2021

The EPB (Earth Pressure Balanced) shield TBM method restrains the ground deformation through continuous excavation and support. Still, the significant surface settlement occurs due to the ground conditions, tunnel dimensions, and construction conditions. Therefore, it is necessary to clarify the settlement behavior with its influence factors and evaluate the possible settlement during construction. In this study, the analytical model of surface settlement based on the influence factors and their mechanisms were proposed. Then, the parametric study for controllable factors during excavation was conducted by numerical method. Through the numerical analysis, the settlement behavior according to the construction conditions was quantitatively derived. Then, the qualitative trend according to the ground conditions was visualized by coupling the numerical results with the analytical model of settlement. Based on the results of this study, it is expected to contribute to the derivation of the settlement prediction algorithm for EPB shield TBM excavation.