• 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.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.

• Journal of the Korean GEO-environmental Society
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• v.20 no.12
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• pp.57-64
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• 2019

A man-made slope has been increased due to the construction of road. This slope lies at risk of rock falling, induced mostly by heavy rainfall. The MOLIT (Ministry of Land, Infrastructure and Transport) recommends the specific dimension of rockfall protection fence (post, wire-rope, and mesh) which should resist 48~61 kJ. However, the energy absorption capacity of each component of rockfall protection fence is not clearly presented. Hence, this study made an effort to compute the energy absorption capacity of each component in analytical and numerical method, and compared with each other.

• Journal of the Korean Geotechnical Society
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• v.26 no.5
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• pp.49-55
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• 2010

The large scale rock falling had occurred on 22nd February, 2007 in the Cheongbuldong valley area of Seoraksan National Park, and the visiting pass had been closed for a while. Similar cases of rock falling have occurred in the latest years according to a great variety of crack, joint, weathering of solid rock and surface water caused by a recent climatic change in the Seoraksan National Park. In this study, rock falling energy was estimated and the movement of rockslide was analysed based on detailed investigation on large scale rockslides occurring at the spot 80 m high from the bottom of the valley. From analysing results, the effective management method for rock falling was proposed. The method could minimized the dangerous factors with no change of natural environment of the National Park.

• Journal of Conservation Science
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• v.37 no.5
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• pp.505-515
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• 2021

In this study, we evaluated the slope stability of the Pohang Daljeon-ri columnar joint (Natural Monuments # 415) and calculated the maximum energy, jumping height and moving distance of rockfalls using a simulation. Based on the results, we established the range of rockfall risk. The slopes of the Pohang Daljeon-ri columnar joint have dip directions of 93.79°, 131.99°, 165.54° and 259.84° from left (SW) to right (NE). Furthermore, they have a fan-like shape. The Pohang Daljeon-ri columnar joints are divided into four sections depending on the dip direction. The measurement results of the discontinuous face show that zone 1 is 125, zone 2 is 261, zone 3 is 262, zone 4 is 43. The results of slope stability analyses for each section using a stereographic projection method correspond to the range of planar and toppling failure. Although it is difficult to diagnose the type of failure, risk evaluation of currently falling rocks requires further focus. The maximum movement distance of a rockfall in the simulation was approximately 66 m and the rockfall risk range was the entire area under slope. In addition, it is difficult to forecast where a rock will fall as it rolls in various directions due to topographic factors. Thus, the installation of measures to prevent falling is suggested to secure the stability based on the results of the rockfall simulations and its probabilistic analysis.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.111-121
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• 2001

Rockfall protection fences are used for diminishing rockfall damage in roads side slopes. In order to install the fences in effective way, the conditions of rock slopes and total predicted impact energy of fa11ing rock should be considered. However, the fences have been constructed without any consideration for lithology, height and slope angle of rock slope in Korea. In addition, the information about the performance of the protection fences, which should be evaluated by in-situ test or laboratory test in order to check out the practical use in the field, is not available. Therefore, in design manual for the rockfall protection fence, the specific details for the installation of this type of fence are not provided yet. The full sized rockfall in situ test was carried out for the calculation of falling energy of rock and the evaluation of the maximum energy absorbing capacity of fence. For this test, the rock slopes whose heights are about 20 m and dip angle of 65 degree, have been chosen. This is because those geometries are mean height and slope angle of most road cut slopes along Korean national highway. Based on the preliminary simulation procedure, four different sizes of concrete ball (0.7, 1.3, 2.3 and 4.3 ton) were prepared and flour different types of protection fence were constructed. The results of this test provide information about the maximum energy absorbing capacity of the fence, kinetic energy of rockfall and restitution coefficient, and these results can be utilized in the establishment of rockfall fence design and construction manual.

• 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 Korea Institute of Building Construction
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• v.20 no.4
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• pp.375-382
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• 2020

Rock drop obstacles on major roads in the border area in South Korea has been installed and operated to prevent and block the movement of enemy units. However, the increase in traffic volume due to the development of the border region causes many problems such as road traffic congestion due to rock drop, traffic safety, and impaired urban aesthetics. Therefore, this study aimed to provide guidelines for demolition and replacement facility installation for rock drop obstacles, which are differently applied to each unit, and to suggest the direction of the Ministry of National Defense's policy regarding maintenance cost for necessary rock drop obstacles required for operation. In this study, as part of a guideline study on the removal of rock drop obstacles and the installation of alternative facilities, a standard unit price was suggested for essential rock drop obstacles, so as to be used as judgment data when deciding whether to remove rock drop obstacles.

• Geotechnical Engineering
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• v.20 no.6
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• pp.44-47
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• 2004

본 기술은 와이어로프의 중간 부위와 단부에 코일스프링을 설치하여 하중 작용시 압축으로 저항하게 하는 낙석방지 울타리의 제작ㆍ설치 기술이다. 이는 낙석 발생시 고유진동수가 작고 큰 변형률이 유도되므로 접촉시간이 길어 와이어로프에 발생하는 장력을 감소시키고 충격흡수능력을 향상시켰으며, 압축으로 저항하여 와이어로프가 먼저 파단된 후 스프링이 항복하도록 하여 안전성을 향상시킨 기술이다.(중략)

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.373-381
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• 2014

It is difficult to predict the magnitude of a rockfall with respect to the shape, volume, and weight of the rock mass, as a rockfall exhibits erratic behavior that depends on the slope geometry, such as the height and dip of the slope. In this study, a field survey was conducted on the slopes of Ulleung-Do, South Korea, where rockfalls frequently occur along coastal roads, to classify the mode of rockfalls and estimate their magnitude. This study also analyzed the effects of rockfall behavior on roads by applying a simulation technique. Agglomerate and trachytic rocks distributed across the study area produce rockfalls in a differential weathering rockfall mode and a toppling rockfall mode. In terms of rockfall weight, trachytic rockfalls were 2-3 times heavier than agglomerate rockfalls. An analysis of rockfall behavior from the simulation indicates that the impact energy on the road exceeded the absorbing energy of a standard rockfall protection fence; however, the rockfall was secured when a ring-net was applied.