• 지질공학
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• 제25권4호
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• pp.439-447
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• 2015

In this study, specific sections vulnerable to debris flow damage were selected, and a complete enumeration survey was performed for the sections with debris flow hazards. Based on this, the characteristics of the sections with debris flow hazards and the current status of actions against debris flow were examined, and an efficient installation plan for a debris flow damage prevention method that is required in the future was suggested. The results indicated that in the Route 56 section where the residential density is relatively higher between the two model survey sections, facilities for debris flow damage reduction were insufficient compared to those in the Route 6 section which is a mountain area. It is thought that several sites require urgent preparation of a facility for debris flow damage reduction. In addition, a numerical analysis showed that for debris barriers installed as a debris flow damage prevention method, distributed installation of a number of small-scale barriers facilities within a valley part was more effective than single installation of a large-scale debris barrier at the lower part of a valley.

• 한국안전학회지
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• 제33권1호
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• pp.128-134
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• 2018

With the increase in frequency of typhoons and heavy rains following the climate change, the scale of damage from the calamities in the mountainous areas has been growing larger and larger, which is different from the past. For the case of Korea where 64% of land is consisted of the mountainous areas, establishment of the check dams has been drastically increased after 2000 in order to reduce the damages from the debris flow. However, due to the lack of data on scale, location and kind of check dams established for reducing the damages in debris flow, the measures to prevent damages based on experience and subjective basis have to be relied on. Under this study, the high-precision DEM data was structured by using the terrestrial LiDAR in the Jecheon area where the debris flow damage occurred in July 2009. And, from the numerical models of the debris flow, Kanako-2D that is available to reflect the erosion and deposition action was applied to install the erosion control facilities (water channel, check dam) and analyzed the effect of reducing the debris flow shown in the downstream.After installing the erosion control facilities, most of debris flow moves along the water channel to reduce the area to expand the debris flow, and after installing the check dam, the flow depth and flux of the debris flow were reduced along with the erosion. However, as a result of analyzing the diffusion area, flow depth, erosion and deposition volume of the debris flow generated from the deposition part after modifying the location of the check dams with the damages occurring on private residences and agricultural land located on the upstream area, the highest reduction effect was shown when the check dam is installed in the maximal discharge points.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.842-848
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• 2018

Motivated by reducing the uncertainties in quantification of debris bed coolability, this paper reports an experimental study on two-phase flow resistances and interfacial drag in packed porous beds. The experiments are performed on the DEBECO-LT (DEbris BEd COolability-Low Temperature) test facility which is constructed to investigate the adiabatic single and two phase flow in porous beds. The pressure drops are measured when air-water two phase flow passes through the porous beds packed with different size particles, and the effects of interfacial drag are studied especially. The results show that, for two phase flow through the beds packed with small size particles such as 1.5 mm and 2 mm spheres, the contribution of interfacial drag to the pressure drops is weak and ignorable, while the significant effects are conducted on the pressure drops of the beds with bigger size particles like 3 mm and 6 mm spheres, where the interfacial drag in beds with larger particles will result in a descent-ascent tendency in the pressure drop curves along with the fluid velocity, and the effect of interfacial drag should be considered in the debris coolability analysis models for beds with bigger size particles.

• 한국산학기술학회논문지
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• 제17권9호
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• pp.34-44
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• 2016

본 연구는 소하천을 대상으로 홍수로 인한 교량에서의 유송잡물 집적을 방지하기 위한 저감시설에 대한 실험연구이다. 일반적으로 소하천은 태풍 및 집중호우 시 유송잡물에 의한 구조물 피해가 빈번하게 발생하고 있으나 이러한 피해에 대한 저감대책은 전무한 실정이다. 국외에서는 유송잡물로 집적으로 인한 피해저감시설로 수직분리대방식, 말뚝시설방식, 스위퍼 방식에 대해 소개하고 있다. 이에 본 연구에서는 유송잡물 저감시설 중 스위퍼를 대상으로 실규모 집적실험을 통해 저감능력을 검토하고자 하였다. 스위퍼는 교각전면부에 설치하여 자력회전을 통해 유송잡물을 우회시켜 교각에 유송잡물이 집적되지 않게 만드는 시설이다. 실규모 실험을 위해 소교량 모형을 실물크기로 제작하였으며, 유송잡물 길이와 흐름조건에 따라 스위퍼 설치 전 후 집적실험을 통해 저감능력을 검토하였다. 실험결과 유송잡물의 길이가 길어지거나 유속이 적을 경우 집적률이 높게 나타나는 것으로 나타났다. 스위퍼 설치에서 따른 유송잡물의 집적률은 스위퍼 설치 전에 비해 최소 55%에서 최대 88%의 유송잡물 집적률이 저감되는 것으로 확인되었다. 이러한 결과로 판단할 때 유송잡물 잠재능력이 높은 소하천에 스위퍼를 설치할 경우 유송잡물 집적으로 인한 교량의 안정성 확보 측면에서 유리할 것으로 판단된다.