• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.548-552
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• 2003

During the last few decades, the frequency and distribution of rockfalls have been increased in Korea due the development of rock slope in mountain areas. Although the scale of, falling block of rockfall was small, there were some casualties of lives and loss of properties. In order to reduce damage from rockfall, analysis on rock slope indanger of rockfall should be carried out. Thus, the simulation softwares for rockfall behavior analysis have been introduced. In this study, geotechnical investigation and input data for rockfall simulation are described with the comparison among four commercially available rockfall simulation softwares. Finally, rockfall simulation works are described by exmining a case of inaccessible rock-slope of potential rockfall in Korea.

• 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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• 2005.03a
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• pp.719-724
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• 2005

It conducted an analysis and the research against kinetic energy distribution, velocity and bounce height according to rockfall characteristics using rockfall simulation program in cut-slope. This study considered kinetic energy and bounce height of rockfall for efficient establishment of rockfall protection fencefence that is countermeasure in cut-slope.

• 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 Korean Geotechical Society Conference
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• 2000.11a
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• pp.629-634
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• 2000

Rockfall protection fence which is used for mitigation of rockfall hazard, has been constructed without consideration of lithology, height and dip angle of rock slope. However, those factors should be considered for the construction of the protection fence. In addition, the protection fence should be evaluated its performance by in-situ test in order to utilize the fence effectively. This is the first full sized rockfall test in Korea. For this test, the rock cut slope whose height is about 20 m and dip angle is 65 $^{\circ}$ has been chosen. Based on the preliminary simulation procedure, four different concrete balls (0.5 ton, 1.0 ton, 2.0 ton and 5.0 ton) were prepared and four different types of protection fence were constructed. The results of this test will be utilized in the establishment of rockfall protection fence construction manual.

• 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.

• 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.

• Journal of the Korean Geotechnical Society
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• v.23 no.11
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• pp.67-76
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• 2007

The characteristics of rockfall are determined by virtually all factors and conditions e.g. the physical figure of the slope such as inclination, height, roughness, the elemental figure of the slope such as vegetation and material deposited, and the shape and weight of the rockfall itself. Although it is one of the major factors to be considered in rockfall simulation, little attention has been given to the weight of the rockfall. And, since the size of the rockfall is dominated by joint spacing, the distribution of the rockfall block weight can be predicted as a function of the joint spacing. In this study, the weight distribution of rockfall was estimated by using the method of volumetric joint count, $J_{\nu}$, based on joint spacing, and $RQD-J_{\nu}$. The results indicate that the weight distributions were analogous in two methods, and the distribution was to be $75.3{\sim}76.7%$ for 200 kilograms or lesser, $15.0{\sim}16.6%$ for $200{\sim}400$ kilograms, and $6.7{\sim}9.7%$ for 400 kilograms or more, which show good matches with the actual on-site weight distribution. Therefore, the weight distribution of rockfall suggested in this paper is able to be considered as appropriate data for rockfall simulation.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.06a
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• pp.103-116
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• 2003

Rockfall Protection fence is one of the most common rockfall Protection methods in Korea. If rockfall protection fences are required along the road or railway, their location, height and capacity, in terms of the maximum kinetic energy that they can absorb, should be specified. Within this paper, the best practice of rockfall barrier is introduced. Modern rockfall simulations as a means to define risks, protection requirements, dynamic loading and height of potential structures and selection of appropriate placement is presented. Technical possibilities of rockfall barriers and their actual limits are presented. Safety concepts based on probabilistic approaches are proposed. Recent studies peformed in other countries show that Flexible Barriers are also a feasible system to stop and retain debris flows. Finally an outlook onto further development is given.