• Journal of the Korea Institute of Building Construction
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• v.20 no.3
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• pp.235-243
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• 2020

In recent years, the use of high-strength concrete has increased with increasing height and enlarging scale of the buildings However, it has been pointed out that the use of high-strength concrete is the most serious problem compared to ordinary concrete in terms of the spalling of concrete cross sections caused by fires. For this reason, fiber cocktail methods, which are made of polypropylene fibers, nylon fibers, etc., are mainly used to improve the fire resistance performance. However, the majority of research on high-strength concrete to which the fiber cocktail method was applied is mainly focused on the effect of reducing spalling, and few studies have investigated and analyzed the effect of micropores produced by melting PP fibers on the long-term durability of high-strength concrete after a fire. Therefore, in this study, the effect of micropores on the depth of carbonation was examined through carbonation tests and microstructure analysis, assuming high-strength concrete to which fiber-mixed construction method was applied, which caused fire damage.

• Journal of the Korean Geosynthetics Society
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• v.17 no.3
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• pp.19-32
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• 2018

Gravel Compaction Pile (GCP) method is currently being designed and constructed by empirical method because quantitative design method has not been developed, leading to various types of and frequent destruction such as expansion failure and shear failure and difficulties in establishing clear cause and developing measure to prevent destruction. In addition, despite the difference with domestic construction equipment and material characteristics, the methods applied to the overseas ground is applied to the domestic as it is, leading to remarkable difference between applied values and measured values in variables such as bearing capacity and the settlement amount. The purpose of this study was, therefore, to propose a reasonable and safe design method of GCP method by analyzing the settlement and stress behavior characteristics according to ground strength change under GCP method applied to domestic clay ground. For the purpose, settlement amount of composite ground, stress concentration ratio, and maximum horizontal displacement and expected location of GCP were analyzed using ABAQUS. The results of analysis showed that the settlement and Settlement reduction rate of composite ground decreased by more than 60% under replacement ratio of 30% or more, that the maximum horizontal displacement of GCP occurred at the depth 2.6 times pile diameter, and that the difference in horizontal displacement is slight under replacement ratio of 30%.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.2
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• pp.51-59
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• 1996

In case waste disposal site is to be constructed close to the underground facilities such as LPG storage cavern which is completely maintained by groundwater pressure, it is generally requested that the possibility on leachate contamination of cavern area be reviewed and the countermeasure, if it is estimated cavern area is severely affected by leachate, be taken into consideration. Prediction was performed and leachate control plan was made using by analytical and the numerical analysis on the leachate migration which is likely to happen at the area between the proposed waste disposal site and the underground LPG storage cavern located at the U petrochemical complex. Analytical solutions were obtained by the conservative mass advection-diffusion equation and the effect of advection and dispersion factor on the leachate migration was reviewed through peclet number calculation and the functional relationship between the factors and leachate transport velocity was established, which leads to enable us to predict the leachate transport velocity without difficulties when different parameters (factors) are used for analytical solution. Numerical solutions were obtained by FEM using AQUA2D which is for the simulation of groundwater flow and contaminant transport. 3-D discrete fracture models were simulated and fracture flow analysis was performed and feasibility study on the water-curtain system was conducted through the fracture connectivity analysis in rock mass. As results of those analyses, it was interpreted that the leachate would trespass on the LPG storage cavern area in 30 years from the proposed wate disposal site and the vertical water-curtain system was effective mathod for the prevention of leachate's migration further into the cavern area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.310-315
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• 2017

Although studies evaluating the effects of the blasting vibration on the adjacent structures from various angles have continued, cases of securing the safety of the adjacent buildings and researching the proper blasting method for the field condition by analyzing the vibration waveform of the measuring field while performing the open pit blasting are poor. Therefore, it is necessary to present a remedy for blasting pattern selection through test blasting that is appropriate for field conditions, and is economical and efficient. In this study, open pit blasting work was conducted based on the separation distance applied according to the standard blasting method by test blasting and the vibration regulation standard in the road expansion construction site to measure the blasting vibration value, and the vibration prediction equation by blasting methods was examined using a regression analysis computer program to calculate K, N, and R of the confidence level 95%. By setting the blasting allowed vibration standard of the test blasting target area to 0.3cm/sec, and the charring weight and blasting method by the separation distances according to the blasting vibration estimation equation of the open pit blasting guideline and the blasting vibration estimation equation of the test blasting were compared/analyzed, it was possible to identify the factors that increased the working expenses. In addition, the measurement and analysis of the adjacent structures during open pit blasting and the blasting vibration were performed after selecting the most adjacent structure to the open pit blasting spot to analyze the problems on the test blasting procedure and analysis method in the open pit blasting design/construction guidelines, which appeared in the process of completing open pit blasting construction, and a remedy is presented.

• Water for future
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• v.18 no.4
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• pp.327-333
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• 1985

The flow pattern of the nearshore current generated around the breached breakwaters and river-mouth was simulated by numerical model in the case of the inclined incident wave without river discharge when the detached breakwaters were installed at the river-mouth area for the protection against the blockade of the river-mouth. The validity of the numerical model was testified y comparision with the results obtained through the hydraulic model test at the fixed bed. The deformation of the topographic features around the river-mouth and the detached breakwaters was examined through the three-dimensional hydraulic model test at the movable bed. The usefulness of the detached breakwater work for the protection against the blockade of the river-mouth was identified by the experimental results.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.330-335
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• 2005

Reliable predictions of the movement of earth retaining structures and the ground adjacent to braced walls in urban excavation are often difficult due to many variable factors. The ground settlement and the damage of adjacent structures in urban excavation has been an important issue. Therefore, the stability of the adjacent structures must be secured with the excavation support and research on the protection of adjacent structure is necessary. This study showed a countermeasure method for case of damage behavior in urban excavation.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.417-422
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• 2003

Rockfall mitigation methods have been widely constructed along railway lines but aren't estimated with any economic analysis methods up to now. Therefore, this study applied a benefit-cost analysis to rockfall mitigation method to determine whether it is indeed an economically efficient construction. The Benefits were estimated based on data collected from disaster history, and included three types of benefits that are originated by reduction of train accident, train delay and rockfall removing cost. The costs included both construction cost and the maintenance cost of the selected method. This analysis could clarify the investment effect of rockfall mitigation method that would be built at rockfall prone slope.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.153-173
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• 1993

폭약은 탄광에서 석탄이나 각종 광물을 캐거나, 건설토목현장에서 암반 제거를 위해서 주로 사용되었다. 전쟁에서 군사용으로 파괴를 위한 목적으로 사용되기도 하였으나, 최근의 동서화해 분위기와 남북통일이 무르익는 시대적 조류로 볼때 더이상 파괴용으로의 사용은 제어될 것이고 이제는 평화를 위하여, 건설을 위하여, 산업발전을 위하여 더 많이 사용되어지고 응용되어질 것이다. 작금의 첨단산업의 발달과 산업의 고도화로 우리 화약 업계에도 첨단발파기술의 개발에 많은 관심과 연구.개발을 진행중이다. 첨단발파기술의 응용사례를 소개하면, 건축토목 분야에서 노후 고층빌딩 및 굴뚝의 철거, 노후 교량 및 공장시설의 철거등에 활용되고 있으며, 위락서비스 분야에서 응용으로는 불꽃놀이를 들 수 있다. 최근에는 첨단 과학 장비를 이용하여 각종 꽃불의 모양이 음악과 미술등 예술적인 기능을 기억시킨 컴퓨터를 활용하여 보다 고차원의 공예술품(공학-예술)을 만들어낸다. 아울러 각종 기공식 발파시에도 예술적 기능과 웅장함을 가미하여 그 화려함을 극치에 다다르게 한다. 그외에도 로켓트 발사추진제등의 우주 개발에의 응용, 석유시추등 해양개발에의 응용, 각종 공학 실험연구에의 응용, 폭발 가공에의 응용, 의학에의 응용, 철강산업에의 응용 등으로 그 숫자를 이제는 일일이 나열하기 힘들 정도로 광범위해졌다.

• 전기의세계
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• v.46 no.7
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• pp.68-71
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• 1997

지중선은 가공선에 비해 공급신뢰성이 높고, 설비보안에 유리하며, 도시미관을 저해하지 않는 장점이 있지만 공사비가 가공선의 12-20배 정도 고가이어서 공사에 막대한 투자비가 소요되기 때문에 가공선건설이 곤란한 도심지역을 제외하고는 지중선건설을 지양하고 있다. 그러나 국가경제가 성장함에 따라 국민생활권이 도심지로 집중하면서 도시가 와밀해졌고 이로 인해 도심부하가 급증하여 오히려 지중선건설은 날로 증가하고 있는 실정이다. 또한 지중선건설에는 막대한 투자재원 확보외에도 사업에 어려움이 많은데 그중에 대표적인 것이 지중토목설비를 적기에 건설하는 것으로서 이 어려움은 앞으로의 차량증가에 따른 도로혼잡과 함께 더욱 심화될 전망이며 이에 대한 근본대책 마련이 시급하다. 이상과 같은 관점에서 볼 때 향후 지중선분야 기술은 케이블 compact화 및 저손실 대용량 케이블 및 신공법 개발에 주력해야 할 것이다. 특히 막대한 투자비를 들여 건설한 지중선은 그 수명기간동안에 고장없이 고품질의 전력을 수용가에 공급하는데 이상이 없어야 하며, 이는 설비운영의 과학화를 통하여 지속적으로 케이블 성능을 보존하므로서 가능하다고 하겠다.

• Journal of KSNVE
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• v.3 no.4
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• pp.300-312
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• 1993

폭약은 탄광에서 석탄이나 각종 광물을 캐거나, 건축토목 현장에서 암반제거 를 위해서 주로 사용되었다. 전쟁에서 군사용으로 파괴를 위한 목적으로 사용되기도 하였으나 최근의 동서화해 분위기와 남북통일이 무르익는 시대적 추세를 볼때 더 이상 파괴용으로의 사용은 억제될 것이고 이제는 평화를 위하여 건설을 위하여 산업 발전을 위하여 더많이 사용되어지고 응용될 것이다. 작금의 첨단산업의 발달과 산업 의 고도화로 우리 화약업계에도 최근에는 첨단발파기술의 개발에 많은 관심과 연구 개발을 진행 중이다. 첨단발파기술의 응용사례를 소개하면, 건축토목분야에서 노후 고층 빌딩 및 굴뚝의 철거, 노후교량 및 공장시설의 철거 등에 활용되고 있으며, 위락 서비스분야에서 응용으로는 불꽃놀이를 들 수 있다. 최근에는 첨단과학장비를 이용하여 각종 꽃불의 모양이 음악과 미술등 예술적인 기능을 기억시킨 케비테이션 를 활용하여 보다 고차원의 고예술품을 만들어낸다. 아울러 각종 기공식 발파시에도 예술적 기능과 웅장함을 가미하여 그 화려함을 극치에 다다르게한다. 그외에도 로켓 발사추진제등의 우주개발에의 응용, 석유시추등 해양개발에의 응용, 각종 공학실험 연구에의 응용, 폭발가공에의 응용, 의학에의 응용, 철강산업에의 응용 등으로 그 숫자를 이제는 일일이 나열하기가 힘들 정도로 광범위 해졌다.