• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.796-805
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• 2005

Most rockfall prevention net among the rockfall prevention equipment that is constructed in around the road is actuality lack of function by quantitative research insufficiency etc.. Most of rockfall prevention net are composed to setting needle, perpendicular and horizontal wire rope and wire net. Also, function of rockfall prevention net depend on setting needle and the wire net and perpendicular and horizontal wire rope are fixed by setting needle. when unreasonable load is offered setting needle, rockfall prevention net can lose the function and happen continuous falling off of rockfall prevention net. Because rockfall prevention net have a such structural defect, improvement had been required in reply. So in this paper, spot application of Rock Bolt & Net Connection method and falling rock support ability are estimated by numerical analysis. As a result, when Rock Bolt & Net Connection Method is applied to cutting slope, decreases of stress and displacement is examined than current rockfall prevention net.

• 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.24 no.3
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• pp.15-21
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• 2023

Although standards related to falling stone facilities are established in Korea, the absorption energy of the rockfall prevention net is evaluated from the passage of rockfall and destruction of the rockfall prevention net on field test. The existing PVC coating net does not sufficiently suppress the rockfall load and tears frequently occur, and a high-strength wire rockfall net was developed to prevent. In this study, the performance was analyzed through field tests of the existing PVC coating net and the developed high-strength rockfall net (1,000 MPa, 2,000 MPa).

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.53-59
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• 2014

In order to obtain basic data for reasonable design of rockfall prevention net unreasonably being designed according to experiences, this paper determined a standard cross section and analyzed the effects of parameters such as inclination and height of slope faces, rockfall weight, separation distance on rockfall behaviors such as bounce height, kinetic energy and passage rate. The weight of rockfall changed from 400 kg to 700 kg and then to 1,000 kg. With the height of 20 m as the standard, the test was conducted with the inclination at $63^{\circ}$ and $55^{\circ}$ which may affect rockfall behaviors. Analysis was made while changing the fall height of rockfall from 3 m to 15 m and then to 20 m, thereby analyzing and evaluating changes in maximal kinetic energy occurring in the base of slope. According to the analysis result, in designing a rockfall prevention wire net, a design considering various conditions including inclination of the slope, expected size or weight of rockfall, situation of the slope and the shape of rockfall, and rockfall trace is judged necessary beyond the current uniform application.

• Journal of the Korean GEO-environmental Society
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• v.11 no.12
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• pp.47-56
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• 2010

The construction of new roads and the consistent extension of already-existing roads or the line-shape revision of those roads are increased with the governmental investment to SOC facilities currently. Accordingly, the road cut slopes are in the trend of rapidly increasing. As the road slope has increased, a lot of human and property damages has entailed consequently and in the local case, numerous studies have carried out aiming at minimizing this damages caused by the rockfall and landslide. In general, standard falling rock prevention facility has employed for most of the local road slope based on "Guide for Installation and Management of Road Safety Facilities" published by MLTM(the Ministry of Land, Transport, and Maritime Affairs) but profound doubt has raised as to whether this rockfall prevention facility would function properly enough to prevent rockfall efficiently without any damages in case of actual occurrence of rockfall. In addition, it is a reality that in most cases, such work is relied on overseas technology as a whole as the local technical level is low and in case of rockfall prevention net, it is judged that a study on rockfall prevention net that is able to endure more powerful rockfall energy is required as the problem including net bursting is taken place as a result of enough bearing force being failed to be demonstrated due to its partial weak point(not uniformly made). Under this background, in this study, three kinds of model depending on mesh size of expanded metal that is considered to have an adoptability as rockfall prevention net, as target are selected and characteristics depending on mesh size of expanded metal is intended to be researched through a pull-out test performance by using pull-out test equipment rockfall prevention net.

• 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.24 no.2
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• pp.25-30
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• 2023

The high-strength rockfall net developed in this study is to replace the fallout prevention net method using PVC coating net made of core wire thickness 3.2 mm and tensile strength 290-540 MPa class steel wire. General PVC coating net have low performance, and in the event of falling rocks or surface loss, they cannot withstand the load and are torn, which rather adds to the damage. Developed rockfall net was manufactured using steel wires with a core wire thickness of 2.8 to 3.2 mm and a tensile strength of 1,000 to 2,000 MPa. Test method was referred to the international standard Steel wire rope net panels and rolls-Definitions and specifications (ISO 17746:2016), and was conducted in accordance with the provisions of the punching test. Through indoor punching tests, the load-displacement curves of the general PVC coating network and the developed high-strength capture net (1,000 and 2,000 MPa) were compared, and the maximum Pull-out load was analyzed to be improved by 324.47% (2,000 MPa high-strength net).

• Journal of the Korean GEO-environmental Society
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• v.15 no.11
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• pp.53-59
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• 2014

It has been generally recognized that the conventional rockfall protection nets have several problems to actual field application in the aspect of shock absorption, lack of pullout bearing capacities, and net damages. Because of the recognition, authors have tried to develop a new rockfall protection system consisted of shock absorption parts and hexagonal net configuration. In the previous research by the authors, the performance of the newly developed rockfall protection system has been investigated through the laboratory tests and the full-scale testing. In this study, subsequently, numerical analysis program is organized to make a confirmation of the structural stability and performance. For the correct design procedure of the hexagonal net system, it is essential to understand the various mechanical behavior of the entire system. It is also important to be reproduced the systematic characteristics of the system acquired by laboratory and full-scale testing by numerical analysis in order to carry out the numerical experiment to understand various mechanical behavior of the system. As a conclusion, the hexagonal net has better performance in mechanical and physical behavior compared with that of the rectangular net. Furthermore, due to the hexagonal net shows a good performance in aspect of the load distribution, it gives a good alternative in long-term management of the rockfall protection net.

• The Journal of Engineering Geology
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• v.12 no.4
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• pp.367-378
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• 2002

Recently, the number of tunnels on national roads has been increased due to the trend that construction of the large-scaled cut slopes is limited because of the environmental issues. Therefore, the slope failures of tunnel portal have often occurred. The tunnel portal in use has limitations on selection of the countermeasure and construction against slope failure. In the cases of Suanbo hot springs 1 and 2 tunnel portals, seedding was chosen and constructed as the countermeasureof slope failure when the tunnel was first built but collapsed in April, 2002. In this study, the failure sites were examined accurately through the site investigation and an efficient countermeasure according to stability analysis is presented. It is shown that it is very efficient to use resloping for Suanbo hot springs 1 tunnel and concrete buttress, rock anchor to reinforcement countermeasure, and attached rockfall prevention net by dividing the site into 3 sections for Suanbo hot springs 2 tunnel.