• Explosives and Blasting
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• v.18 no.2
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• pp.23-34
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• 2000

• Computational Structural Engineering
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• v.8 no.1
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• pp.30-38
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• 1995

이방향 천공 발파공법의 실용성을 입증하여 실시공에 착수하기 위해서는 수치해석을 통하여 사전에 종방향 및 방사방향 천공발파에 따른 지표면에서의 지반진동의 영향을 알아보는 것이 필요하였다. 정확한 현장조건과 발파하중이 주어진 상태에서의 정밀해를 구하기 위해서는 시공상의 발파패턴대로 전체 발파공을 모형화하는 것이 필요하나 앞서 언급한 바와 같이 해석목적상 기존공법과 신공법의 지반응답의 차이를 비교하는 것이 주목적이였기 때문에 해석조건을 동일하게 가정하고 발파공도 대표적인 방향성을 가지는 1개공만을 선택하여 해석을 수행하였다. 기존 종방향 천공 발파공법과 신공법인 이방향 천공 발파공법의 상대적 비교를 위한 3차원 동적 해석결과, 관심의 대상이 되는 터널 직상부의 경우 기존의 종방향 천공 발파에 비해 이방향 천공발파는 진동이 두드러지게 감소함을 알 수 있었으며 이는 발파공의 방향성에 따라 지반응답이 크게 영향을 받는다는 것을 의미한다. 따라서 터널굴착시 문제시 되는 지상구조물의 위치에 따라 발파공의 위치를 적절히 조절함으로써 문제발생 예상지역의 진동치를 감소시킬 수 있을 것이라 판단된다. 그러나 이러한 잇점은 확대발파전 파이롯트 터널이라는 자유공간이 존재할 때만 가능하므로 이방향 천공 발파공법은 TBM의 효용성을 극대화시킨 것이라 할 수 있다.

• Explosives and Blasting
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• v.20 no.1
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• pp.51-59
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• 2002

터널의 1차 숏크리트 라이닝의 설계선 외측 부분에 발파시 주변에 방사상으로 발생되는 균열들을 제어하기 위하여 Smooth-Blasting 공법 적용하여 외곽공에 정밀폭약(FINEX)을 사용한다. (주)한화에서는 Smooth-Blasting 공법의 중요사항인 폭약선정 사항에서 기존의 G/D 계열의 FINEX를 동일 발파조건에서 여굴 및 미굴의 발생을 최소화시키기 위해 에멀tus 계열의 New FINEX를 개발하여 약종 별로 동일 발파 패턴을 적용하여 터널에서 시험발파를 실시하여 천단 및 좌, 우 측벽의 여굴의 발생범위를 계측장비와, Half Casting을 측정하였다. 현장 시험발파를 통한 결과 흑운모 편마암(일축강도 $1500{\;}Kg/\textrm{cm}^2)$에서 여굴제어는 G/D계열의 FINEX 보다 EMX 계열의 New FINEX가 15~50% 정도 감소가 되었다.

• Explosives and Blasting
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• v.22 no.4
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• pp.23-29
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• 2004

Non-electric detonator was developed to improve the blasting efficiency of electric detonator. It is increasingly utilized in surface and tunnel blasting due to its safety in external electric shock, precise delayed time, and decrease in blasting vibration and noise. The paper describes the detonating system of non-electric detonator, principle operating and planning methods, and case history so that it can be contributed to improve blasting technology.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.486-491
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• 2000

Blasting vibrations velocity had been used to design blasting pattern and predict damage-possibility of structures. As vibration levels are currently required to estimate the damage concerning human-body and livestock, so measured vibration velocities must be transformed into vibration levels. In this study, the digital filter program was developed to transform measured data into vibration levels. Simple harmonic vibrations and measured data obtain by Blastmate series (Instantel Inc.) were applied to the digital filter program. As a result, simple harmonic vibrations and measured data were successfully transformed into vibration levels using the developed program. Measured data from any instrument with ASCII output-function will similarly be transformed into level units.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2000.09a
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• pp.241-246
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• 2000

Blasting vibrations velocity had been used to design blasting pattern and predict damage-possibility of structures. As vibration levels are currently required to estimate the damage concerning human-body and livestock, so measured vibration velocities must be transformed into vibration levels. In this study, the digital filter program was developed to transform measured data into vibration levels. Simple harmonic vibrations and measured data obtained by Blastmate series (Instantel Inc.) were applied to the digital filter program. As a result, simple harmonic vibrations and measured data were successfully transformed into vibration levels using the developed program. Measured data from any instrument with ASCII output-function will similarly be transformed into level units.

• 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.42 no.3
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• pp.49-57
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• 2024

Pre-fracturing is the blasting method to weaken the rock mass prior to the main excavation. This study aims to evaluate the effectiveness of pre-fracturing by using half the explosive charge typically employed in conventional blasting designs. Field tests conducted at a quarry in Gapyeong showed that noise levels were reduced by 2.7 dB due to the decreased amount of explosive per blast hole, and vibration levels were controlled to the precision vibration control blasting standard. Rock weakening was confirmed through induced cracks observed on the surface and core samples, and it was noted that the weakening effect of the blasting decreased as the burden increased. The vibrations from conventional blasting were found to be lower than those from pre-fracturing. This was attributed more to the geological conditions, such as joints, rather than the blasting design factors like explosive amount, burden, and the number of free face.

• Explosives and Blasting
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• v.23 no.3
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• pp.43-56
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• 2005

The defoliation velocity is tile rate of propagation of a detonation in an explosive. An explosive's velocity of defoliation(VOD) can be used to indicate a number of important characteristics regarding the product's performance under specific field and test conditions. Also, it is useful quality monitoring technique and call be measured accurately and easily at borehole and testing sites. This paper discusses the relevance of the detonation velocity of explosives in blasting. Attempts were made to classify detonation velocities and offer an interpretation of blasting process which will be useful to blasting engineers. But it was found that there is not necessarily a direct relationship between defoliation velocity and explosive quality or efficiency.

• Journal of the Korean Professional Engineers Association
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• v.23 no.5
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• pp.30-34
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• 1990