• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.523-530
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• 2002

Recently, while rockfall occurs very frequently, a lot of researches on the rockfall protection fence Is in process. But the rockfall protection fence has been installed unrelated to slope characteristics, rockfall shape and rockfall height. Therefore, in this study we suggested the effective protection fence model considering about rockfall energy and energy absorbing capacity and we verified the model by field test. According to these results, it is more reasonable to evaluate rockfall energy based on the results of simulation program, which can be consider effects of energy decrease, than use the simplified method proposed by Japanese road association. And rockfall energy is affected by the size of supports and wire rope and the space of supports. As the results of comparing rockfall energy with energy absorbing capacity, type$\circled1$(the space of supports is changed to 3.0m)can be available for generally expected rockfall except the rock slope over 30m heights. But rockfall protection fence installed at the field, it should be partially reinforced after consideration of slope particularities and construction conditions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.293-298
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• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ, But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations. In the result it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.461-466
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• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ. But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations In the result, it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.5
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• pp.297-302
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• 2020

Korea has many mountainous regions, and slope collapse that can lead to damage in road facilities and loss of lives often occurs. Rockfall-protection facilities are necessary to reduce such damages. Among these facilities, the standard Korean rockfall-protection fence is designed to resist 50 kJ of rockfall impact energy. However, the range of rockfall energy significantly varies depending on the condition of the slope, and it sometimes reaches up to 100 kJ. Thus, providing several types of standardized rockfall-protection fence is necessary to address the different rockfall impact energy for efficient response to rockfalls. This paper presents a study on standardized rockfall-protection fence for various rockfall impact energy using finite-element analysis. According to the results, standardized rockfall-protection fences against rockfall impact energy of 30 and 100 kJ were proposed and have been verified.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.153-162
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• 2005

The structural specification of the rockfall prevention fence installed on the road section is computed according to the hypothetic rockfall energy, and the absorbable energy of the rockfall prevention fence is defined as the sum of the absorption energies of the wire rope, one of the components, the steel support and the wire netting. But the results of the field tests confirmed that the absorption energy of the rockfall prevention fence is not the sum of the energies sustainable by the components, but it is affected by the absorbable energy of part of the components. This shows there are problems with the method of computing the absorption energy of the rockfall prevention fence of the road. So in this paper, as a way of solving the problems, the effects of improving the performance through positional changes of the existing components and the effects of improving the performance through structural changes by expanded metal are checked through tests, and a plan was proposed to solve the problems with the standards of installing the conventional rockfall prevention fence.

• Tunnel and Underground Space
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• v.24 no.4
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• pp.275-281
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• 2014

The performance criteria of rockfall protection fence and reliability index were investigated considering characteristic of rockfall energy occurred at 160 cut slopes in national highway. As a result of study on statistic of variables that decide rockfall energy using Monte-Carlo simulation, the degree of slope was normal distribution type, mass of rockfall and height of slope was lognormal distribution type. The rockfall energy follows lognormal distribution because of statistical characteristic of mass of rockfall. The reliability index of rockfall protection fence was 0.678 and the failure probability of was very high as 24.9%. Proposed performance criteria of rockfall protection fence considering the scale of domestic rockfall energy is maximum 500 kJ and the range of reliability index was from 1.028 to 1.956. the failure probability of rockfall protection fence was from 14.8 to 2.5 percent if applying the performance criteria using the reliability index.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.499-511
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• 2022

In this study, a vertical drop test was carried out to identify the performance of flexible wire rope rockfall protection fence by 100 kJ rockfall energy according to ETAG 027. The flexible wire rope, which consists of wire rope and spring. is especially enhanced the elasticity and flexibility so that it can be longer elongated when the rope is impacted by rockfall compared to original wire rope, and that results longer increase of contact time between rockfall and wire rope and increase rockfall energy absorption capability and decreases rockfall impact force. The test results shows that the plastic deformation occurred in middle post and the final deflection of the middle post was 1.15 m, which is lower than 2.0 m determined by ETAG 027. This vertical test verified the flexible wire rope rockfall protection fence can successfully absorb 102.9 kJ rockfall energy.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.581-584
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• 2008

This study analyzed activity of rockfall and its effect factor by the shape and mass. We performed research on the kinetic energy distribution, velocity and bounce height according to the rockfall characteristics using rockfall simulation program in cut-slope. In addition, this study discussed how to utilize kinetic energy and bounce height of rockfall for efficient establishment of rockfall prevention fence which is a countermeasure to cut-slope.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.910-920
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• 2008

In Korea, more than 70% of the territory consists of mountains. Therefore, the construction of roads and railways has generally involved with a steep rock slope in which the event of rockfalls are often occurred due to the weathered rock conditions and rainfalls etc. This is dangerous when the rock falls into the road and railway on which vehicles and trains are running. In order to prevent such rockfalls, the rockfall protection fence consisting of post, wire rope, and PVC coating steel net has most used at the bottom of rock slopes. In a general practice, an absorbing rockfall energy, 50kJ is specified by the Ministry of Construction and Transportation. However, questions still remain about whether the rockfall protection fence works effectively or not. In this study, a typical wire rope used in the standard rockfall protection fence was replaced by the high carbon steel wire rod and to validate its capacity of rockfall energy absorbing the field rockfall tests were conducted. The testing results show that a new rockfall protection fence using the high carbon steel wire rods can absorb the rockfall energy more than 50kJ and 20% of construction cost was saved in comparison with the previous rockfall protection fence.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.35-45
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• 2005

The rockfall protection fence is one of the most common rockfall protection methods in Korea. The typical rockfall protection fence consists mainly of three parts ; H-beam supports, wire meshes, and wire ropes. The design of the rockfall protection fence is made such that the total energy absorbing capacity of the fence. Therefore, resulting from the combined energy absorbing capacity of the three parts is larger than the falling energy of rocks. In present study, a new rockfall protection fence, constructed using expanded metals instead of the existing wire rope and wire mesh for the typical type of rockfall protection fence, was evaluated on its performance by conducting both laboratory and field tests. Also, for a comparison, the same tests were performed on the typical rockfall protection fence. The test results revealed that the expanded material is an economic alternative to the existing protection materials and the expanded metal rockfall protection fence exhibits the higher energy absorbing capacity compared to that of the typical rockfall protection fence.