• Explosives and Blasting
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• v.22 no.1
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• pp.67-74
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• 2004

Blasting in urban area has become a serious issue in our living because it causes inconvenience to the resident living by construction area. Therefore, the practical solution and the better method for reducing blasting noise are highly required. However, finding practical solutions for the blasting noise is very difficult due to the lack of basic data and insufficient existing research. In order to overcome the limitation of existing sound barrier, we applied a new material to multi-layer soundproof system in the construction site, Kuksabong Tunnel in Yang Nyung-Ro. The statistical method was used to analyze blasting noise data. Through all these processes, it was verified that the soundproof system in this study was very effective method to decrease blasting noise.

• Journal of KIBIM
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• v.10 no.4
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• pp.11-21
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• 2020

With increasing interest and research on smart cities, there is also an increasing number of studies on urban facilities that can be built within smart cities. According to these studies, smart cities' urban facilities are likely to become high value-added industries. However, the concept of smart city is not clear because it involves various fields. Therefore, in this study, the definition of Next-Generation(N.G) Smart City Facilities with Digital Twin and Digital Chain is carried out through a multidisciplinary approach. Based on this, Next-Generation Smart City Facilities will be divided into High Value-Added Products and Big Data Platforms. Subsequently, the definition of the Digital Chain containing the data flow of the entire process built through the construction of the Digital Twin proceeds. The definitions derived are applied to the Next-Generation Noise Barrier Tunnel to ensure that data is exchanged at the Digital Twin stage, and to review the proposed configuration of the Digital Chain and Data Flow in this study. The platform definition and Digital Chain of Next-Generation Smart City Facilities proposed in this study suggest that it can affect not only the aspects of data management that are currently in the spotlight, but also the manufacturing industry as a whole.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.563-563
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• 2013

Railway noise has been a social issues nowadays in our community. This paper discusses the environmental noise problem along railway lines. We overview the noise level and noise exposed populations due to conventional and high speed train operation at first. Then we introduce variety of noise reduction schemes to protect the community based on an engineering approach. Some applicationcases to reduce the noise will be demonstrated. Finally, we propose the noise barrier tunnel as a tool of a generic solution to reduce the community noise along railway lines.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.44-45
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• 2020

The purpose of this study was to contemplate the effectual waterproofing materials and construction methods for the restoration of underground infrastructures using precast arches(PC-Arch). Until now, there were no proper waterproofing guidelines for waterproofing precast arch tunnel when restoring cultural heritage or building underground infrastructures for noise control. Asphalt membrane sheets were commonly used, but the efficacy of waterproofing done on the precast segment was vulnerable. This study aims to examine the Synthetic Rubber Polymerised Gel(SRPG) proposed in ISO TR 16475, a guideline for the repair of water-leakages, and to demonstrate field applicability based on the waterproofing solution used on the road improvement project in front of Changgyeonggung Palace in Yulgok-ro, Seoul, Republic of Korea.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.153-170
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• 2022

Waterjet has been comprehensively used in urban areas owing to a suitable technique for cutting concrete and rock, and low noise and vibration. Recently, the abrasive waterjet technique has been adopted and applied by the Korea Atomic Energy Research Institute to demolish concrete plugging without disturbing and damaging In-situ Demonstration of Engineered Barrier System in the disposal research tunnel. In this study, the use of abrasive waterjet in the tunnel was evaluated for practical applicability and the existing cutting model was compared with the experimental results. As a variable for waterjet cutting, multi-cutting, water flow rate, abrasive flow rate, and standoff distance were selected for the diversity of analysis. As regarding the practical application, the waterjet facilitated path selection for cutting the concrete plugging and prevented additional disturbances in the periphery. The pump's noise at idling was 64.9 dB which is satisfied with the noise regulatory standard, but it exceeded the standard at ejection to air and target concrete because the experiment was performed in the tunnel space. The experimental result showed that the error between the predicted and measured cutting volume was 12~13% for the first cut and 16% for second cut. The standoff distance had a significant influence on the cutting depth and width, and the error tended to decrease with decrement of standoff distance.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.522-532
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• 2015

In the present study, a tunnel type soundproof wall with partial opening is proposed to reduce the environmental noise caused by railway vehicles traveling on bridges, which affects residents of high-rise apartment buildings; the study also attempts to minimize load due to wind and the weight of the wall. Applying the principles of computational fluid dynamics and structural mechanics, and the ray tracing method, a reduction in noise as well as of the overall weight of the soundproof walls is estimated. Analysis results show that the proposed soundproof wall with a partial opening weighs less, while reducing the wind loading by up to 30%. To prevent direct propagation of sound through openings in the wall, an acoustic louver, which is a type of silencer, could be considered for the opening. In order to achieve a similar noise effect with existing insulation material, the fluid flow and the insulation effect of the acoustic louver are analyzed. As the considered opening is in the range of 30~40% of the total length of the soundproof wall, the noise effect and wind load are reduced by 10dB and 25% respectively. Consequently, opening some part of tunnel type soundproof walls and installing louvers on the wall openings can have the effects of weight-reduction and reduced wind load. If a partial opening is applied with proper sound material application, a gain of an additional 5~10dB of noise reduction can be achieved.

• Progress in Superconductivity
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• v.10 no.2
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• pp.99-102
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• 2009

We report our development of the fabrication process of sub-micron scale $Al-AlO_x-Al$ tunnel junction by using electron-beam lithography and double-angle shadow evaporation technique. We used double-layer resist to construct a suspended bridge structure, and double-angle electron-beam evaporation to form a sub-micron scale overlapped junction. We adopted an e-beam insensitive resist as a bottom sacrificing layer. Tunnel barrier was formed by oxidation of the bottom aluminum layer between the bottom and top electrode deposition, which was done in a separate load-lock chamber. The junction resistance is designed and controlled to be 50 $\Omega$ to match the impedance of the transmission line. The junctions will be used in the broadband shot noise thermometry experiment, which will serve as a link between the electrical unit and the thermodynamic unit.

• Tunnel and Underground Space
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• v.10 no.1
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• pp.80-91
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• 2000

Open cut mining of limestone is generally considered to be more advantageous than underground mining in recovery, grade control, economics, and safety, but it causes substantial environmental pollutants such as ground vibration, noise, dust. It also changes ground surface and may destroy vegetation. The Halla limestone mine which lies adjacent to Baikdu mountains range is selected for a model study. To reduce environmental hazards, and to conserve original surface and woods, both open cut and underground mining methods must be adopted. In case of sub-level sloping. a unit block of 87m high, 70m wide, and 100∼l20m long is suggested with an estimated overall recovery of 42%. Some suggestions to reduce the environmental hazards are also included. The followings must be considered in determining the degree of fragmentation; the discontinuity conditions in the rock mass and the charge concentration both at the bottom and column of the hole. In addition to adopting a barrier wall for reducing environmental hazards, the probable production from underground mining is also discussed.

• Journal of KIBIM
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• v.9 no.4
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• pp.51-61
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• 2019

In the general manufacturing sector, prototyping used to reduce the risks that can arise with new conceptual products. However, in AEC area, it does not mass-produce a building, so the prototype itself becomes a building. Therefore, it is challenging to have prototyping of the same scale as the real thing, and the prototyping process in architecture is very inefficient. The prototyping process in the design stage typically assumes making a scaled model, partial model, or digital model. However, it is difficult for these models to correspond to the actual building and the environment of time and space such as scale, material, environment, load, physical properties and deformation, corrosion, etc., unlike the actual building. When using the digital twin concept in the prototyping process, it is possible to measure performance from the design stage to the operation stage. The digital twin was found by a method for monitoring based on physical twins and real-time linkage in the operation stage. Therefore, if the digital twin concept is applied at the design stage, it is possible to predict performance using not only current performance but also history information using real-time information. In order to apply the digital twin concept to the prototyping design process, we analyze the theoretical considerations and the prototyping design process of the digital twin, analyze the cases and research results where the prototyping design was applied, Provide an applied prototyping design process. The proposed process is tested through a pilot project and analyzed for potential use.