• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.6
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• pp.605-614
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• 2015

A room-and-pillar underground structure is characterized by its grid-type array of room and pillar. As a result, its construction and economical efficiency can be governed by excavation sequence. In this study, the construction period by the drill and blast method which can be treated as a main sequence for excavation was examined by considering the regulation for blasting and construction standard of estimation in Korea. To evaluate the construction period for the room-and-pillar underground structure constructed in 4 kinds of square-type area ($30{\times}30{\sim}57{\times}57m$), the concurrent excavation pattern which was suggested in the previous researches was used. From the suggested condition, the total construction period by drill-and-blast method can be estimated with the consideration of the construction area, number of jumbo drill and faces in operation.

• Explosives and Blasting
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• v.31 no.1
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• pp.23-32
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• 2013

Construction vibration such as explosive blast, hydraulic breaker, vibratory roller, pile driving noise and so on, injuries in areas around the construction sites. In particular, underwater sound caused by ground vibration is propagation such as structure borne noise. Vibration and underwater sound due to construction activities may cause injury to river, sea or land fish farms near construction sites. The purpose of present study is to measure the sound pressure level and frequency analysis of the underwater noise generated by ground vibration(Blasting, hydraulic crawler drill, hydraulic breaker, vibratory roller). Underwater noise were monitoring by a hydrophone (TC 4013) and recorded, analysis were made using a by software (Prosig).

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.511-524
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• 2016

Since a room-and-pillar underground structure is characterized by its grid-type array of room and pillar, its economical efficiency can be governed by excavation sequence. In this study, the construction period by the drill-and-blast method as a excavation method for a room-and-pillar underground structure was examined. In addition, the parallel excavation sequence was considered as the main sequence of a room-and-pillar underground structure. Sequences of mucking and support installation were derived to estimate the total excavation cycle by taking the case of a road tunnel into consideration. From the excavation cycle of room-and-pillar underground structure, the relationship between available maximum and minimum numbers of jumbo drill machines depending on the number of faces in operation was suggested.

• Explosives and Blasting
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• v.30 no.2
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• pp.52-58
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• 2012

A TBM launching shaft in DTL2 Contract 915 site is located in a typical hard Bukit Timah granite formation and lots of blasting work is required for shaft sinking. The original blast design used the electric detonator and ANFO blasts consisting of 30 holes per one blast with 1.5 m depth of drilling hole. However, significant delay of work and poor progress were expected due to the limitation of the number of blasting hole and strict vibration regulation on retaining systems. To overcome such constraints, an efficient new blasting method which can improve productivity and satisfy vibration limit was required. The revised blast design, using triple-deck blasts with electronic detonators and cartridge emulsion explosives, gives better construction performance and can reduce construction time. Such a new blasting technique can be effectively used for similar underground projects in the future where the volume of rock blasting is significant.

• Explosives and Blasting
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• v.22 no.3
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• pp.97-101
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• 2004

The using of Gun powders are getting grower than power due to the road opening, tunnel digging, the highest building, the pound digging on the construction industry, it also happen blasting accident as well, and it become society issue more than more. In this study, The check list far the human cause of the most rate among the blasting accident was developed in availing of accident investigation chart for the analysis of the blasting accident of already developed and FTA technique analysis with the analysis systematically of blasting accident. And then, Analysis for the application was carried out in construction cite, availing of the check list. As results, The most error has broken out at charge work, an uncomfortable processes, among the blasting work. Thus, It is a matter for consideration with improvement work.

• Explosives and Blasting
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• v.36 no.4
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• pp.9-15
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• 2018

Since the rock fragmentation by blasting can affect the subsequent processes including loading, hauling and secondary crushing, its control is essential for the assessment of blasting efficiency as well as production cost. In this study, we were analyzed the rock fragmentation by the direction of artificial joint. The underground blasting experiments were performed after forming the vertical and horizontal artificial joints. The blast fragmentation was conducted by the split-desktop which is a 2D image processing program. As a result, it was found that the horizontal artificial joint was evaluated to have lower overall the size of muck pile than the vertical artificial joint and the distribution of the size of muck pile was varied. It is possible that the direction of artificial joint could suppress the occur of oversize muck pile and control to a certain size or less.

• Explosives and Blasting
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• v.29 no.1
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• pp.17-26
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• 2011

In this study, the pollutants contained in water and soil samples taken from the explosive demolition site were examined to investigate the effects on environment, and management plan of non-point source pollution in the demolition site was suggested through characterizing the movement of the pollutant with time. As results, pH value of the water and soil samples after the demolition work was 8.5~9.3 which exceeds the Korean environmental criterion of water and soil range due to calcium hydroxide compounds in the concrete. The concentration level of heavy metals caused by the explosive demolition doesn't exceed the environmental criterion of water and soil doesn't exceed the environmental criterion of water and soil quality, and the influence of water and soil pollution on the environment was not considered. The concentration of the heavy metals was analyzed and that of Cr, Cu, Zn and Hg among the heavy metals increased after the drilling and explosive demolition. This says that concentration of the heavy metals during explosive demolition works needs to be monitored. The most pollutants with time or rain dilution into the demolition site decreased and this means that the pollutants caused by the explosive demolition might have influenced to vicinity of the demolition sites as non-point pollution.

• Explosives and Blasting
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• v.25 no.2
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• pp.47-60
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• 2007

The blast demolition technology has been used to demolish various industrial facilities and tall buildings since 1950s in the advanced countries such as USA and U.K. It is now considered as one of safe demolition methods in the above countries. In Korea, several companies have tried to introduce blast demolition technology in the early days of the 1990s. However, this technology is still at the beginning stage and not fully adopted due to situation of avoiding technology transfer by overseas technical tie-up companies, lack of objects to be demolished and low level recognition on blast demolition. This technology shall be considered as a cutting edge technology to be applicable to demolition of skyscrapers, various industrial structures and factory buildings in the near future. Blast demolition of a pier structure was carried out under the site condition where there were already the constructed 2 pier structures of up and down line which had safety problems in an expressway construction project. The pier structures need to be demolished and reconstructed for a short period of time in consideration of the construction work process to be followed.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.2 s.21
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• pp.45-50
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• 2006

When we build the tunnel, occasionally, the blasted section exceed the designed section because of geological properties and the lack of blasting technologies, and the exceed section is remained as over break after the construction of tunnel lining. When the underground water leaks with silt and clay through the cracks of rocks, the large over break cause a structural stability problem in tunnel, and the back charging of over break is very important subject, because the undoing of back charging cause the drop of crashed rocks and serious problem in the stability of tunnel lining. Therefore, the theory of blast is studied and purpose the structural analysis of back charging and propose the safe method about the drop of crashed rocks.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1996.03a
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• pp.95-106
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• 1996

건물발파해체 설계 및 시공에 있어서 중요한 공정의 하나는 불안정성을 유도하도록 실시하는 건물의 주요 지지부 기둥에 대한 발파이다. 이와 관련된 요소기술로는 기둥단면에 따라 천공패턴을 결정하고 적정장약량을 산정하는 것과 폭파시 파괴된 파편의 비산에 대한 방호기술을 들 수 있다. 비산은 인접건물에 대한 피해와 인명사고들을 유발할 수 있으므로 사전에 철저한 대책이 강구되어야 할 대상이다. (중략)