• Tunnel and Underground Space
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• v.13 no.5
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• pp.403-411
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• 2003

Controlled tunnel blasting by deck charge was suggested and simulated by PFC and FEM analyses. Analyzed results showed that suggested method is efficient in fragmentation and able to decrease in vibration level because of decreased amount of charge per delay and dispersion of deck charge. This phenomena was explained by failure mechanism and proved that it can be successfully applied to tunnel blasting.

• Explosives and Blasting
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• v.20 no.1
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• pp.25-34
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• 2002

일반적으로 도심지에서 터널 시공을 위한 암반굴착 작업은 주변 보안물건에 대해 직접적인 피해를 유발시킬 수 있는 공해요소인 진동을 허용기준값 이하로 제어할 수 있으면서 상대적으로 시공성과 경제성이 뛰어난 공법으로 수행되어야 한다. 본 사례에서는 각내의 대표적인 문화시설인 예술의 전당 하부를 통과하는 우면산 터널 공사현장에서 암반굴착공법으로 고려한 TTM 장비를 이용한 기계굴착, 플라즈마 공법, 유압장비를 이용한 할암공법, 겔파쇄 공법, 미진동파쇄기를 이용한 공법, 진동제어발파공법에 대한 현장 적용성을 시험시공 등을 통해 평가한 내용과 결과를 제시하였다. 비록 각 도심지 터널의 현장 상황이나 주변 여건에 따라 이 현장에서의 시험시공 내용이나 적용 결과를 그대로 적용할 수는 없겠지만, 진동제어 암반굴착 공법에 대한 시험시공이나 선정 과정에 이 사례연구가 개략적인 참고자료로 활용될 수 있을 것이다.

• Explosives and Blasting
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• v.20 no.4
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• pp.17-28
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• 2002

Safety concern is one of the most important parameters in the design of building demolition by explosive blasting, Accidents were sometimes reported due to the flying chips of fragmented materials In building demolition work in urban area. Laboratory experiments were performed to investigate the failure behavior of reinforced concrete pillars under blast loading and to develop an effective protection technique. Sixteen reinforced concrete pillars were constructed. The failure behavior and the flying chip velocities were observed by means of a high-speed camera. Protection scheme was designed and the effects of several protection materials were investigated. Two kinds of non-woven fabrics and wire net were tested as protection materials. The results showed that reinforcing bar was one of the important factors to determine specific charges, and that mesh size of wire net and tied-up method affected the protection of flying chips. Control of gas effects is also a key to the control of flying chips. It was recommended to use both wire net and non-woven fabrics as primary and secondary protection materials. Such protection scheme was successfully applied to the explosive demolition of apartment buildings.

• Explosives and Blasting
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• v.21 no.3
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• pp.1-10
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• 2003

터널굴착발파공법의 하나인 V-cut발파공법은 터널굴착기술이 발전되는 과정에서 초기에 개발되어진 기술이나 작업의 간편성과 효율성으로 인하여 많은 터널굴착공사에서 이용되고 있는 발파공법이다. V-cut발파공법은 일자유면 상태에서 V형으로 심발공을 발파하고 심발공에 의해 형성된 자유면을 이용하여 확대공으로 굴착공간을 넓히는 발파 방법이며 심발발파의 굴진장에 의해 단일발파당 굴진장이 결정된다. V-cut발파법이 개발된 이래 V-cut발파의 굴진장을 증대시키기 위한 방법으로 심발발파공의 구속저항을 감소시키기 위해 보조심발공을 발파하여 형성된 자유면에 의해 심발공의 최소저항선거리를 줄여 발파하였으나 심발공의 구속저항이 감소되지 않아 발파효율이 증대되지 않았으며 발파진동 또한 가장 크게 발생하였다. 이와 같은 현상은 최소저항선거리의 감소효과에 대한 발파기술상의 이론에 문제가 있기 때문이다. 본 연구에서는 V-cut발파법의 심발공에 대한 구속저항감소효과가 발현될 수 있는 조건들을 검토하여 최소저항선거리의 감소효과가 발현될 수 있는 조건을 제시 하여 심발공의 발파효율을 증대시키고 발파진동이 적어지는 발파방법을 제안하려 한다.

• Proceedings of the KSEE Conference
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• 2007.03a
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• pp.175-186
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• 2007

• Explosives and Blasting
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• v.26 no.1
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• pp.49-55
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• 2008

Mechanical excavation techniques employing tunnel boring machines (TBM) and rock splitters have been proposed to minimize rock damage for tunnel and underground waste repository facilities. Such a mechanical excavation, however, is extremely expensive and not applicable in all cases. For these reasons, controlled blasting using notched charge holes have been suggested to achieve crack growth along specific directions and inhibit growth along other directions. This study introduces a dynamic fracture process analysis code to simulate fracture processes of rock which has a notched charge hole.

• Explosives and Blasting
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• v.35 no.4
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• pp.36-47
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• 2017

Due to civil complaints on vibrations and noises arising from blasting, mechanical excavation has been widely used for tunneling rather than the method of blasting, especially in the case of being in a close-proximity of 10M-20M range to a safety-thing. However, mechanical excavation, though less, it does increase the cost of whole construction project as the period of excavation is much prolonged from lack of constructability. This study aims to research and develop an effective blasting method that can ensure the constructability of shortened excavation period whilst not compromising the safety of the safety-things in a proximity to the blasting site by using a combination of an electronic detonator that can accurately control its delay period and a Low Vibration Explosives(LoVEX) that is effective on vibration control.

• Explosives and Blasting
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• v.31 no.1
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• pp.1-10
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• 2013

In blasting demolition, a method would be chosen among many depends on shape and system of a structure and its surround. To demolish using explosives a structure, which is asymmetric and with high aspect ratio, pre-weakening, explosive locations, detonating delay, and surround conditions are needed to be considered in front to design blasting demolition plan. In this study, to over turn asymmetric and high aspect ratio structure in safe, a simulation using a software named Extreme Loadings for Structures, ELS, had performed. In results, it is achieved optimized pre-weakening shapes and locations, which prevent kick back motion of the structure when it collapse, by analyzing moment distribution caused by pre-weakening. And of structural collapse and by minimizing asymmetric structure's torsional moment. Also, after the demolition, simulation results are also compared with actual collapse behavior. In results, it is confirmed the accuracy of collapse behaviour simulation results, and in blasting demolition, kick back motion can be controled by adjusting pre-weakening shape and location, and the torsional moment of an asymmetric structure also can be solved by optimizing detonation locations and its time intervals.

• Explosives and Blasting
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• v.31 no.2
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• pp.14-24
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• 2013

The most effective way of the rock removing works in the downtown area is to removing rocks by splitting the rock by blasting with small amount of explosives in the hole. However environmental factors not only limit the applications but also increase the forbidden area. As this is a distributed multi-stage blasting method and to reduce vibration by applying the optimized precisioncontrol-blasting method, it is applicable in all situations. The process is to fix the stemming-help plastic sheet to the hole entrance when stemming explosives and insert detonator and explosive primer with same delay time, two or three sets. This method is more efficient in the downtown area where claims and dispute from vibration are expected. This method is easily usable by designing blast pattern even in the area where delay time blasting is difficult after multi-stage explosive stemming due to short length of blast hole (1.2~3.0m) and there is no detonator wire shortage or dead-pressure.

• Explosives and Blasting
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• v.26 no.1
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• pp.39-48
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• 2008

Using Electronic Detonators which is well known for controlling vibration, we have been studying Orchestra Blasting Method, OBM, for many years to transform the unpleasant blasting sound to favorable sound in some job-sites such as tunneling and bench blasting which have to been taken place near some structures needed great care. In this study, we focus on rhythmical sense. First, we acquired individual wave from a shot. With the program named the Program Blasting Wave, PBW, it was analyzed and found that its best delay time was 34ms and 50ms was acceptable. Also, delay time was fitted into the music which was accepted after analyzing the rhythm. As a result, the blasting sound along with the music felt comfortable as if the music was played with base drum.