• 한국지반공학회논문집
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• 제24권5호
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• pp.65-78
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• 2008

절토사면 및 천심도 터널의 경우 불연속면을 따른 블록의 미끄러짐 및 회전 등이 안정성에 큰 영향을 미친다. 절토사면이나 터널의 초기 설계 단계에서 안정성 검토를 위해 수치해석을 널리 사용하는데, 대부분의 상용화된 프로그램들은 연속체 해석에 기반을 두고 있다. 불연속면을 고려하여 연속체 해석을 수행할 수도 있으며, 절리를 포함한 암반자체의 강도를 감소시킴으로써 모사하는 것이 대표적인 방법이다. 또한, 연속체 해석방법인 Mohr-Coulomb 모델에 편재 절리모델 (ubiquitous joint model)을 적용함으로써 불연속면을 고려하는 방법이 있다. 절토사면의 수치해석시 주 입력치인 절리암반의 점착력, 마찰각, 탄성계수 등은 암반분류법(rock classification system)에 의한 경험식으로 도출할 수 있으며, 본 논문에서는 이 중 RMR 및 GSI 시스템에 의한 경험식을 통해 얻은 입력치를 실제 위험절토사면에 적용함으로써 두 시스템의 차이를 비교해 보고자 하였다. 또한 RMR 및 GSI 시스템으로 도출한 입력치에 편재절리모델을 혼합하여 적용함으로써 계측을 통해 얻은 변위량 및 변위양상과의 차이를 분석하였다. 분석 결과 GSI 시스템으로 도출한 입력치에 편재절리모델을 혼합하였을 경우의 수치해석결과가 실제현장의 변위량 및 변위양상과 가장 유사한 결과를 얻을 수 있음을 확인할 수 있었다.

• Geomechanics and Engineering
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• 제14권4호
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• pp.367-376
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• 2018

Samples composed of coal and rock show different mechanical properties of the pure coal or rock mass. For the same coal seam with different surrounding rocks, the frequency and intensity of rock burst can be significantly different in. First, a method of measuring the strain variation of coal in the coal-rock combined sample was proposed. Second, laboratory tests have been conducted to investigate the influences of rock lithologies, combined forms and coal-rock height ratios on the deformation and failure characteristics of the coal section using this method. Third, a new bursting liability index named combined coal-rock impact energy speed index (CRIES) was proposed. This index considers not only the time effect of energy, but also the influence of surrounding rocks. At last, a new approach considering the influences of roof and/or floor was proposed to evaluate the impact capability of coal seam. Results show that the strength and elastic modulus of coal section increase significantly with the coal-rock height ratio decreasing. In addition, the values of bursting liability indexes of the same coal seam vary greatly when using the new approach. This study not only provides a new approach to measuring the strain of the coal section in coal-rock combined sample, but also improves the evaluation system for evaluating the impact capability of coal.

• 한국콘텐츠학회논문지
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• 제22권2호
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• pp.80-87
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• 2022

국내에서 이재민과 재해가 예상되는 일시 대피자에게 제공되는 재해구호용품 중 대부분이 임시주거시설인 구호소 환경에 맞지 않고 사용자들이 요구하는 기능이나, 크기, 형태를 가지고 있지 않아 만족도가 낮은 것으로 평가된다. 본 연구는 재해구호용품 중 구호소 매트리스의 사용환경에 대한 문제점 제시를 통해 사용자 Need를 분석하였고 이를 통하여 방재디자인 기반 구호소 가변식 에어매트리스를 개발하였다. 사용성, 편의성, 내구성 등에 객관성을 확보하기에는 연구 데이터의 한계점이 있지만 기존 섬유 매트의 대량 보급의 어려움과 발포플라스틱 계열 매트의 기능적 단점을 가변형 에어 매트리스로 해결하였다. 개발된 가변형 에어매트리스는 이재민과 일시대피자가 장기간 구호소 생활시 생길 수 있는 육체피로, 질병 악화, 수면부족 등에 도움을 주고 생활안정을 도모하여 재활의지를 갖게 될 것으로 기대된다.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 추계학술논문발표회 논문집
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• pp.11-16
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• 2008

The trend of constructing skyscraper has arisen to the offistel and apartment complex due to the lack of exploitable land and urbanization. But, the phenomenon of the multi-story buildings is different from the regular building because of the possibility of mass disaster in fire. Therefore, Analyzing and comparing our actual condition and Japanese, It is going to be suggested that the introduction of fire escape ladder for residents in emergency.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2007년도 춘계학술논문발표회 논문집
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• pp.373-378
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• 2007

• 한국환경과학회지
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• 제16권12호
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• pp.1439-1449
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• 2007

Heavy snowfall was occurred over the south-western part of the Korean Peninsula called as Honam Districts, on two days from 21 December 2005. The development mechanism of snowfall and its characteristics were analysed using observation and numerical data provided by Korea Meteorological Administration. In comparison with other years Arctic air mass developed and maintained during all December 2005 due to active planetary waves with three branches. And jet streams at lower and higher levels make easy development of snow convection cells. Especially thermal low induced by mesoscale heat and dynamic sources, also help the developments of convection cells in strong ascension. The understanding the relation between synoptic and mesoscale circumstance, therefore, is also important to predict the heavy snowfall and to prevent the disaster.

• 한국해양공학회지
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• 제30권4호
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• pp.320-326
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• 2016

Rip current forecasts, based on intensity, are marked in four levels—notice, watch, warning, and danger. However, numerical results are represented by current vectors, whose magnitudes are then converted into predictive levels. In the present study, the rose diagram is adapted as a determinative forecasting index and examined for the case of an ideal rip channel consisting of surface, bottom, and averaged currents. Further, it is employed in the sensitivity analysis of wave-induced currents generated by wave conditions at the Haeundae Beach. The simulation of surface onshore and bottom undertow currents is accomplished by including a mass flux term in the wave-averaged continuity equation.

• Smart Structures and Systems
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• 제24권3호
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• pp.403-414
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• 2019

Offshore drilling has become a key process for obtaining oil. Offshore platforms have many applications, including oil exploration and production, navigation, ship loading and unloading, and bridge and causeway support. However, vibration problems caused by severe environmental loads, such as ice, wave, wind, and seismic loads, threaten the functionality of platform facilities and the comfort of workers. These concerns may result in piping failures, unsatisfactory equipment reliability, and safety concerns. Therefore, the vibration control of offshore platforms is essential for assuring structural safety, equipment functionality, and human comfort. In this study, an optimal multiple tuned mass damper (MTMD) system was proposed to mitigate the excessive vibration of a three-dimensional offshore platform under ice and earthquake loadings. The MTMD system was designed to control the first few dominant coupled modes. The optimal placement and system parameters of the MTMD are determined based on controlled modal properties. Numerical simulation results show that the proposed MTMD system can effectively reduce the displacement and acceleration responses of the offshore platform, thus improving safety and serviceability. Moreover, this study proposes an optimal design procedure for the MTMD system to determine the optimal location, moving direction, and system parameters of each unit of the tuned mass damper.

• Geomechanics and Engineering
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• 제15권4호
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• pp.1017-1027
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• 2018

To explore the influence of coal thickness on the mechanical behavior and the failure characteristics of rock-coal-rock (RCR) mass, the experimental investigation of uniaxial compressive tests was conducted first and then a systematic numerical simulation by particle flow code (PFC2D) was performed to deeply analyze the failure mechanical behavior of RCR specimens with different coal thicknesses in conventional compression tests. The overall elastic modulus and peak stress of RCR specimens lie between the rock and the coal. Inter-particle properties were calibrated to match the physical sample strength and the stiffness response. Numerical simulation results show that the deformation and strength behaviors of RCR specimens depend not only on the coal thickness, but also on the confining pressure. Under low confining pressures, the overall failure mechanism of RCR specimen is the serious damage of coal section when the coal thickness is smaller than 30 mm, but it is shear failure of coal section when the coal thickness is larger than 30 mm. Whereas under high confining pressures, obvious shear bands exist in both the coal section and the rock section when the coal thickness is larger than 30 mm, but when the coal thickness is smaller than 30mm, the failure mechanism is serious damage of coal section and shear failure of rock section.

• 한국화재소방학회논문지
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• 제26권6호
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• pp.7-14
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• 2012

본 연구에서는 화재현장에서 유류와 관련되어 실화나 방화의 매개체로 사용되어 화재가 발생했을 때 석유류의 정확한 분석기법을 개발하기 위하여 발화지점 주변의 온도분포, 연소되고 남은 물질의 흔적과 GC/MS 분석으로 물질의 종류를 확인하는 것을 가연성 고체와 비교해서 실험하였다. 연구결과 천장에 도달하는 온도는 휘발유와 시너는 점화되자마자 불꽃이 생성되어 천장의 온도가 매우 빠르게 상승하여 그곳에 물질이 있을 경우 2차 화재발생이 전개될 것으로 나타났다. 연소된 후에 바닥에는 가연성 고체와 유류가 상이한 특징적인 패턴을 형성하였다. 연소된 장판은 탄화수소계열이지만 가스검지관을 통해 반응을 확인한 결과 가연성 고체는 아무런 반응을 띠지 않았으나 유류는 즉시 반응을 하였고 그 연소물질을 7일이 경과된 후에 GC/MS로 분석한 결과 유류의 존재를 확인할 수 있었다. 화재조사가 복잡한 과정이지만 물질의 특성을 통한 세밀한 조사는 유류화재를 입증하는 데 중요하고 GC/MS분석기기를 통해 실체를 확인하는 과정이 요구된다.