• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.183-183
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• 2011

전 국토의 65%가 산악지형으로 이루어져 있는 우리나라는 도로개설 및 산업기지 건설, 대규모 주택단지 개발 등으로 자연사면을 변형시키는 규모나 빈도가 증가하고 있고, 최근에는 기상이변에 의한 집중호우가 빈번히 발생하여 절토사면에서 낙석이 발생할 위험이 점점 높아지고 있는 실정이다. 낙석방지를 위한 대책공법으로는 낙석방지 망, 낙석방지 울타리 등이 있으며 이중에서 낙석방지 울타리는 국내의 국도 낙석방지 대책공법 중 70% 이상을 차지하고 있다. 그러나 국내 설계지침에는 낙석방지 울타리에 대한 다양한 성능등급과 성능평가를 위한 표준화된 시험방법이 제시되어 있지 않아 현장여건을 고려하여 적절한 낙석방지 울타리를 선정하고 낙석방지 울타리들의 성능을 비교검토하기에 어려움이 있다. 유럽의 경우 유럽연합 출범이후 낙석방지 시설에 대한 통합기준의 필요성이 대두되어 유럽 여러 나라의 성능평가 방법과 스위스의 설계지침을 고려하여 2008년에 유럽 통합 지침인 ETAG 27을 제정하였다. ETAG 27에는 낙석방지 울타리의 성능등급이 100kJ~4,500kJ이상 9등급으로 분류되어 있고 성능등급 별로 Service Energy Level과 Maximum Energy Level에 대하여 실물시험을 통한 성능평가 시험과 구성요소에 대한 검증시험을 수행하도록 되어있다. 실물시험은 낙석에너지의 산정과 낙석질량의 타격위치를 정확하게 결정할 수 있는 방법을 이용하여 수행토록 규정되어 있다. 미국의 경우에는 주별로 상이한 설계기준으로 인하여 발생하는 문제를 해소하기 위하여 2003년에 스위스의 설계지침을 준용하여 통합기준인 NCHRP Report 20-07을 결정하였다. NCHRP Report 20-07에는 낙석방지 울타리의 성능등급이 100kJ~5,000kJ까지 9등급으로 분류되어 있고 성능등급 별 낙석질량이 규정되어 있으며 등급별 낙석에너지의 50%와 100%에 대하여 실물시험을 통한 성능평가 시험을 수행하도록 되어 있다. 실물시험은 낙석에너지의 산정과 낙석질량의 타격위치를 정확하게 결정할 수 있는 방법을 이용하여 수행토록 규정되어 있다. 낙석방지 울타리에 대한 국내 설계지침과 유럽과 미국의 설계지침을 비교분석하고 국내에서 수행된 실물실험을 통한 성능평가 연구결과를 검토하였다. 또한 구성요소의 역학적 특성변화가 전체 시스템의 성능에 미치는 영향을 조사하기 위해서 국내 설계 지침에 제시된 낙석방지 울타리에 대하여 컴퓨터 시뮬레이션을 이용한 성능평가를 수행하였다. 이러한 연구결과에 근거하여 국내 설계지침은 현장여건에 따라 적절한 낙석방지 울타리를 선정할 수 있도록 다양한 성능등급을 규정하고, 낙석방지 울타리의 성능을 합리적으로 비교검토 할 수 있게 하는 표준화 성능평가 시험방법과 평가기준을 정립하며, 구성요소의 품질에 대한 신뢰성을 확인하는 구성요소의 검증시험을 포함하는 방향으로 개선될 필요가 있는 것으로 조사되었다.

• Journal of the Korean GEO-environmental Society
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• v.21 no.12
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• pp.17-21
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• 2020

Over 60% of South Korea's land consists of mountainous topography, and recently, due to earthquakes, localized heavy rains and road development, the risks of rockfalls are getting higher. As of now, rockfall prevention facilities are being constructed in 70% of Korean roads cut slope and rockfall protections account for about 20% of them. Rockfall protection's supporting capacity is defined by combining performance of wire mesh, pillars and wire ropes. For the existing constructed rockfall protection, standards of pillars that can absorb 48~61 kJ amount of energy, wire ropes and wire mesh are presented in Guidelines for the installation and management of traffic safety facilities, Rockfall prevention facilities by Ministry of Land, Transport and Maritime Affairs (2008). However, each factor's correlation of absorption energy is not presented so it is uncertain. This study will conduct vertical drop test and identify adequacy of rockfall protection net of displacement quantity calculation factor which is delta and evaluate rockfall protection net's absorbable energy through standards of overseas performance evaluation criteria.

• Journal of the Korean GEO-environmental Society
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• v.23 no.2
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• pp.5-12
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• 2022

In this study, a field test was conducted to present a test method for performance evaluation of a rock fall prevention fence, centering on the vertical drop test among the existing test methods of the rock fall prevention fence. A test to determine the support capacity of a rockfall prevention fence in Korea is usually conducted using a combination of wire mesh, poles, and wire rope, and the location of the impact of falling rocks has been conducted centered on the center of the wire mesh. However, in the case of domestic papers and test data, there is no data on direct hit of post. Therefore, the amount of displacement and weak section were analyzed when the impact on 100kJ class rock energy was hit on the post, centering on the Rockfall Protection fence (highway type No. 2).

• Journal of the Korean GEO-environmental Society
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• v.3 no.4
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• pp.59-66
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• 2002

Designs for rockfall protection systems must consider rock and soil types, the angle of the slope, conditions on top and the toe of the affected area. Rockfall protection fence is installed to block for falling rock from cut slopes and this is one of the most common rockfall protection measures. The capability of the fence is provided that sum of capability of poly vinyl chloride coated wire mesh, steel support and wire rope respectively. But in some case, the rockfall protection fence was not supported rockfall energy less than total capability of the fence through the full scale rockfall tests. Therefore, the objectives of this paper are to indicate the problems of fence capability and to improve the design specifications for the fence.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.63-76
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• 2015

The purpose of this study is to suggest performance levels, a test method, and assessment criteria for the performance assessment to allow standardized tests for rockfall protection systems. The range of rockfall impact energy was determined by using domestic rockfall data and a total of 9 performance levels from 50kJ to 1500kJ were suggested. The performance assessment is implemented by two types of full-scale free-fall impact tests to investigate the serviceability and the maximum capacity as in European and American standards. It was considered to be reasonable that the specimens of rockfall protection systems consist of 3 spans and the concrete block of a polyhedron with 26 faces, similar to spheres, impacts at the center of a center span. Assessment criteria were constructed to investigate whether a rockfall penetrated rockfall protection systems and whether the deformed specimen encroached on the roadway or obstructed the vehicle traffic.

• Journal of the Korean GEO-environmental Society
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• v.21 no.12
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• pp.11-16
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• 2020

It is necessary to assess the proper performance of the existing rockfall prevention net in order to minimize the damage to human lives and property in the event of rockfall. However, there is no standard for performance evaluation of rockfall prevention net in Korea, and only the design of rockfall prevention net exists by calculating energy that can be absorbed energy. Therefore, laboratory pullout test was conducted for the performance evaluation of the rockfall prevention net, cuts and load-displacement characteristics of the PVC coating net used in the laboratory pullout test are determined to identify the performance of the rockfall prevention net.

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.49-57
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• 2009

The governmental investment to SOC facilities currently has increasedthe construction of new roads and the consistent extension of already-existing roads or the line-shape revision of those roads. As a result, the road cut slopes have been increasingrapidly. Unfortunately, human-life damages and property damages frequently occur due to the rockfall and the landslide every year. To reduce those damages, many studies have been performed. The present regulation regarding rockfall protection facilities follows the "Guide for Installation and Management of Road Safety Facilities" issued by MLTM (the Ministry of Land, Transport, and Maritime Affairs) that indicates the standard size of facilities and energy absorbing efficiencies. Most domestic road slopes use standardized rockfall protection facilities based on the regulation. However, there have been doubted about the effectiveness of rockfall protection facilities and the damages caused by rockfalls havebeen increasedevery year. Thus, it seems that relevant studies are necessary on the rockfall protection net being capable of supporting rockfall energies. Accordingly, this study reviews previous literature to investigate the function and the feature of rockfall protection nets and analyzetheir limitations by each type. After that, by using the pullout test device for a rockfall protection net, an experiment on the PVC coating net and the expanded metal is performed under the exact same condition. Finally, the features of the Expended metal is explained with the comparison analysises of load-variation and the confirmation of damaged forms. As a result, there have been founded the problemsof net breaking down and not being able to support due to PVC coating net's material property of disintegration. On the other hand, the Expanded Metal might be expected as a substituteof rockfall protection net according to its capability of support and integration.

• Journal of the Korean GEO-environmental Society
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• v.23 no.3
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• pp.5-13
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• 2022

In this study a test was conducted to identify weak section using 100kJ class rock energy to find out the protection performance of rockfall prevention fences in Korea. Performance rating of the rockfall protection fences is very low (48~61kJ) compared to that of foreign countries and it is necessary to determine whether it can function properly if high rock energy is generated. Furthermore, a reinforcing technology that can improve to 100kJ energy on the existing rockfall protection fences should be developed. Therefore, this study confirmed the protection performance using 100kJ rock energy in the existing rockfall protection fence system (for national road, for highway) and identified weak section of post, wire ropes and nets. Furthermore, it will be used as basic data for developing 100kJ class reinforcement technology without dismantling the existing rockfall protection fence (48-61kJ).

• Journal of the Korean GEO-environmental Society
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• v.12 no.9
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• pp.13-20
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• 2011

There are many mountains in Korean Peninsula, and those used for the construction of roads and railways sectors are forming slopes. Slope collapse occurs with falling rocks and landslide because of the relaxation of the thawing rocks. The heavy rain in summer can also significantly contribute to the process, and abnormal climate change is much more influential than before. Therefore, rockfall-related accidents in rainy season are easily accessible in media every year. There has been a lot of research on application of strengthening compensation of the sections in order to minimize casualties and property damage. Rockfall Protection Net, however, has not been focused on much in the field yet. This study highlights the need of Rockfall Protection Net, since it can segregate the falling rocks inside the net relatively safely. Although there has been a little doubt about the effectiveness of rockfall protection facilities, it is obvious that relevant studies dealing with the solidity of the net are necessary for the rockfall protection net to be capable of supporting rockfall energies. As a result, Expanded metal strength is much more durable compared to the PVC coating net, and it is regarded as an excellent alternative material for the Rockfall Protection Net. In this study, the applicability of Expanded Metal as the alternative of Rockfall Protection Net is verified experimentally.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.49-60
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• 2009

In order to develop a new rockfall protection fence using high carbon steel wire rod (HSWR) material instead of the conventional wire rope material, the author has conducted the laboratory strength tests of both materials and their connections, and carried out evaluation of absorbing rockfall energy through the vertical field rockfall tests. The vertical filed rockfall tests showed that the new rockfall protection fence with 12 rows of the HSWR could absorb more rockfall energy than 50 kJ which stands for the typical design criteria. In addition, when the quantity of HSWR was increased up to the 16 rows, the capacity of absorbing energy was greatly improved. The new rockfall protection fence was successfully applied to the highway rock-cut slope. As a result of the filed application, its constructability was similar to the conventional fence, but its total image was improved as simple and clean. The total construction cost was saved up to 20% in comparison with the conventional one.