• Explosives and Blasting
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• v.32 no.2
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• pp.16-24
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• 2014

In this "Wonju~Jaecheon double-lanes railroad" project, a highway is located at about 13meter above a tunnel. Initially, rock-splitting method was used for the tunnel excavation in order to minimize the possible damage on the highway. The method, however, takes a long time for the tunnel excavation and that may cause other problems like large displacement of tunnel and subsidence of highway ground before the tunnel can be stabilized by supporters. Therefore, the application of electronic blasting method(eDdevII) was recommended to control the blast vibration below 1.0cm/sec as well as to prevent the subsidence of highway ground. The analysis of the influence of tunnel excavation on the highway showed that electric blasting method is permissible for the safe management of the highway. Based on that, the tunnel construction under a highway could be carried out quickly and safely without any damages on the highway.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.27-36
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• 2005

The performance of innovative prestressed support (IPS) earth retention system applied in urban excavation was presented and investigated. The IPS wales provide a high flexural stiffness to resist the bending by lateral earth pressure, and the IPS wales transfer lateral earth pressure to Corner struts. The IPS wale provides a larger spacing of support, economical benefit, construction easiness, good performance, and safety control. In order to investigate applicability and stability of the IPS earth retention system, the IPS system was instrumented and was monitored during construction. The IPS system applied in urban excavation functioned successfully. The results of the field instrumentation were presented. The measured performances of the IPS earth retention system were investigated and discussed.

• Tunnel and Underground Space
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• v.15 no.5 s.58
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• pp.359-368
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• 2005

In case the overburden of a tunnel is too low to adopt NATM, cut and cover method generally can be chosen as alternative. However, in tunneling some area with very low or no overburden between two mountains, the cut and cover method requires additional construction of a couple of tunnel portals and the maintenance of portal slopes until backfilling is completed. As a solution for this problem, increasing the tunnel overburden by raising the ground level can be effective. This paper presents the case study for tunneling at C240 site in Taiwan High Speed Railway(THSR) in which soil-cement filling method was used for pre-banking before tunnel excavation. Cement content of filling material was $2\~4\%$ and thickness of filling a round was $130\~250\;mm$. The stability evaluation for the soil-cement slope and concrete lining of low cover tunnel was conducted by numerical analysis.

• Geotechnical Engineering
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• v.8 no.4
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• pp.81-98
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• 1992

Deep excavation increases utility of underground spaces for high buildings. subways etc. To excavate vertically the underground, safe earth retaining walls and supporting systems should be prepared. Recently anchors have been used to support the excavation wall. The anchored excavation has some advantages toprovide working space for underground construction. In this paper the prestressed anchor loads were measured by load cells which attacted to the anchors to support the excavation walls at eight construction fields. where under-ground deep excavation was performed on cohesionless soils. The lateral pressures on the retaining walls, which are estimated from the measured anchor forces, shows a trapezoidal distribution that the pressure increases linearly with depth from the ground surface to 30% of the excavation depth and then keeps constant value regardless of the stiffness of the walls. The maximum lateral pressure was same to 63% of the Ranking active earth pressure or 17% of the vertical overburden pressure at the final depth The investigation of the measured lateral pressure on the anchored excavation walls shows that empirical earth pressure diagram presented by Terzaghi-Peck and Tschebotarioff could be applied with some modifications to determine anchor loads for the anchored excavation in cohesionless soils.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1999.03a
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• pp.41-50
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• 1999

발파는 토목, 건설현장이나 광산 등에서 암반에 대한 굴착 방법으로서 가장 널리 쓰이고 있는 방법중의 하나이다. 그러나 최근 들어 발파에 의한 진동이나 소음 등의 위해가 사회적 문제로까지 대두하고 있으며, 또한 발파작업에서 작업계획에 대한 결과의 정밀도를 높이기 위하여 조절발파 등 여러 가지 방법들이 연구 발전되어 가고 있는 추세에 있다. 이러한 연구들은 주로 현장 발파작업 및 발파패턴의 설계에 치중되어 있으며 발파모델을 이용한 해석 연구는 다소 미진한 정도이다. (중략)

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.177-178
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• 2022

건설 안전관리는 건설업을 행하는 과정에서 발생하는 사고 나 재해의 발생 원인과 예방을 위한 관리 대책을 수립하여 인명과 재산을 보호하기 위한 모든 활동을 말한다건설현장의 안전사고는 근로자에게는 육체적 8정신적 고통과 노동력의 상실에 따른 경제적 부담이 발생하며 기업 입장에서는 생산력의 저하와 비용의 증가=국가로서도 사회 경제적 손실이 발생함으로 효율적이고 실질적인 안전관리 대책이 반드시 필요하다건설공사가 대형화=복잡화=고층화 및 대규모 지하 굴착과 같은 고난도의 작업이 많아짐에 따라 작업 환경의 특수성과 작업 환경상 높은 위험을 갖게 되었다.

• Explosives and Blasting
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• v.25 no.2
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• pp.71-78
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• 2007

In many cases of underwater blasting in South Korea, the special blasting is mainly used for deepening harbor, installing gas pipes, or well blasting to build a bridge. The procedure of well blasting is almost same with shaft blasting, but the difference is that water is filled in before blasting. In case of deepening blasting under water, the first step like drilling, arranging explosives, and wire connection is done on a barge, then the next step such as charging and tamping is accomplished under water by expert divers. Therefore, underwater blasting needs precise and exact plan before blasting. In this paper, authors would like to introduce a case of underwater blasting for deepening the Busan new port with emulsion explosives and non-electric detonators in order to get some of 8,500TEU out sized container vessels entered into the port and to make safe. Considering environment and vibration, the blasting was controlled to minimized the damage to the lighthouse nearby. It will be great help to many other blasting sites where emulsion explosives and non-electric detonators are used for underwater blasting through this case.

• Journal of the Korea Convergence Society
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• v.5 no.2
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• pp.13-18
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• 2014

In this study, two models due to the configuration of ripper at excavator are investigated by structural and fatigue analyses. The maximum stress and deformation are happened at the axis connected with the body of working device and the direct working part respectively. Model 1 is thought to have more structural durability than model 2. Fatigue life or damage in case of 'SAE bracket history' whose load change is most severest among non-uniform fatigue loads is shown to become most unstable. But life or damage in case of 'Sample history' whose load change is slowest among non-uniform fatigue loads is shown to become most stable. These study results can be effectively utilized with the design of ripper at excavator by anticipating and investigating prevention and durability against its fatigue damage.

• Explosives and Blasting
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• v.36 no.2
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• pp.19-26
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• 2018

The measures for environmental regulations have become more strict over the recent years. Due to vibration and noise arising from blasting, every site that chooses to handle explosives has to be under certain restrictions in its use. Especially a site where a safety thing is situated within close proximity, the chosen method is through mechanical excavation. However, various applications of electronic detonators has made blasting possible where mechanical excavation used to be the only alternative. Hanwha Corporation has developed an electronic detonator, $HiTRONIC^{TM}$, which is an advanced fourth-generation detonator with a high accuracy of delay time(0.01%). At this moment, $HiTRONIC^{TM}$ is widely used in highway and railway construction sites, large limestone quarries, and many other blasting sites where blasting had not been an available option before. In this paper, I would like to introduce a case study on construction of utilizing $HiTRONIC^{TM}$ at a large-scale tunnel site.

• Explosives and Blasting
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• v.34 no.4
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• pp.40-45
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• 2016

Sites, where explosives are used, are constantly under constraint of vibration and noise levels. If a sensitive area is located nearby the sites, mechanical excavation has been preferred rather than blasting. Recently, however, blasting using electronic detonators is applicable in the areas, where previously should be excavated by mechanical methods. $HiTRONIC^{TM}$ is a fourth-generation detonator that utilizes Hanwha Corporation's advanced electronic technology. The detonator contains IC-Chip, which allows delay times between 0~15,000ms with 1ms interval. Furthermore, the product can provide high accuracy(0.01%) for accurate-blasting. Electronic detonator is widely used in highway and railway construction sites, large limestone quarries, and other works. In this paper, several sites, in which HiTRONIC was used, are introduced in order to enhance understanding of electronic detonator.