• Title/Summary/Keyword: 단일공 발파

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A Case Study on the Blasting Analysis of Slope Using Monitored Vibration Waveform (실측진동파형을 이용한 비탈면 발파진동 해석 사례)

  • Park, Do-Hyun;Cho, Young-Gon;Jeon, Seok-Won
    • Explosives and Blasting
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    • v.24 no.2
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    • pp.41-50
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    • 2006
  • Excavation by explosives blasting necessarily involves noise and vibration, which is highly prone to face claims on the environmental and structural aspects from the neighbors. When the blasting carried out in the vicinity of a structure, the effect of blasting vibration on the stability of the structure should be carefully evaluated. In the conventional method of evaluation, an equation for blast vibration is obtained from test blasting which is later used to determine the amount of charge. This method, however, has limitations in use since it does not consider topography and change in ground conditions. In order to overcome the limitations, dynamic numerical analysis is recently used in continuum or discontinuous models, where the topography and the ground conditions can be exactly implemented. In the numerical analysis for tunnels and rock slopes, it is very uncommon to simulate multi-hole blasting. A single-hole blasting pressure is estimated and the equivalent overall pressure at the excavation face is used. This approach based on an ideal case usually does not consider the ground conditions. And this consequently results in errors in calculation. In this presentation of a case study, a new approach of using blast waves obtained in the test blast is proposed. The approach was carried out in order to improve the accuracy in calculating blasting pressure. The stability of a structure in the vicinity of a slope blasting was examined using the newly proposed method.

Influence of Inner-hole Priming Location on Ground Vibration (발파공내 기폭위치가 지반진동에 미치는 영향)

  • Kim, Jae-Woong;Kang, Choo-Won;Ko, Chin-Surk
    • Explosives and Blasting
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    • v.30 no.1
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    • pp.29-36
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    • 2012
  • In this study, the influence of priming location inside a blast hole on the ground vibration has been studied. In most of the previous studies dealing with the ground vibration, the effect of priming location in a blast hole was usually considered in a limited way. Thus, it seems that the results of the studies can be applicable only to the relevant sites. Considering the fact that the mechanism of ground vibration caused by blasting is quite complex, the priming location can have a considerable effect on the ground vibration in certain situations and be an important parameter in a blasting design. To identify the characteristics of the wave propagation according to priming locations, total 72 test blasts were carried out with different spacing, burden, drilling length, and charge, and prediction equations were derived. The characteristics of ground vibration, which was changed according to the priming location, was analyzed by using the nomogram of peak particle velocity (PPV) record. Attenuation relations, which were also dependent on the priming location, were analyzed. In this case, four different amounts of charge, that is, 0.5, 1.6, 5, and 15 kg, were used for the test. This criterion of charge amount is specified in the "Blasting design and construction guidelines to road construction" by the Ministry of Land, Transport and Maritime Affairs of Korea.

Numerical Study on the Reduction of Blast-induced Damage Zone (최외곽공 주변암반의 발파굴착 손상영역 저감에 관한 수치해석적 연구)

  • Park, Se-Woong;Oh, Se-Wook;Min, Gyeong-Jo;Fukuda, Daisuke;Cho, Sang-Ho
    • Explosives and Blasting
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    • v.37 no.3
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    • pp.25-33
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    • 2019
  • Controlling the blast-induced damage zone(BDZ) in mining excavation is a significant issue for the safety of employees and the maintenance of facilities. Numerous studies have been conducted to accurately predict the BDZ in underground mining. This study employed the dynamic fracture process analysis (DFPA) to estimate the BDZ from a single hole blasting. The estimated BDZ were compared with the results obtained by Swedish empirical equation. The DFPA was also used to investigate the control mechanism of BDZ and fracture plane formation around perimeter holes for underground mining blasting.

On the Mechanism of Smooth Blasting on the Rock Containing Discontinuties (불연속면이 존재하는 암반에서의 Smooth Blasting의 기구)

  • 박홍민;이상은
    • Explosives and Blasting
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    • v.14 no.4
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    • pp.13-19
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    • 1996
  • Lately, the improtance of smooth blasting is increasing on every construction fields, suchas underground caves, tunnels, and roadconstruction, etc. The main purpose of smooth blasting is to prevent unnecessary cracks from the base rockwhich preserved permanently and is to gain the smooth fracture plane. So, in smooth blashing, explosives with low detonating velocity are generally used. But it is difficult to discuss general theory on the smooth blashing because the mechanical properties of pertienent rocks are difficult regionally. Accordingly basic reserches on the smooth blasting are demended. In this paper, the mechanisms of the smooth blasting on the rocks containing discontinuities were discussd. Firstly, the writer predicted the formation of fracture plane and unevenness using mathematical methodology, the next the model blast tests were conducted in order to simulate the crack propagation modes from the blast holes. Through the research, the following conclusions were obtained l)The blast test results were in reasonally good agreement with the theoretical prediction. 2)The degree of discontinuity has an influence on the fracture morphology.

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A Study on the Economical Design of Bench Blasting in Lime Stone Quarry (석회석광산에서의 경제적인 벤치발파패턴에 대한 연구)

  • 이천식;정민수;이윤재;송영석;양난주;강대우
    • Explosives and Blasting
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    • v.21 no.1
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    • pp.19-27
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    • 2003
  • 국내 석회석 광산에서는 벤치 발파패턴을 현장의 KNOW-HOW에 따라 가장 경제저인 발파패턴을 적용하고 있다. 그러나 인건비 재료비등 제반경비가 상승함에 따라 좀 더 효율적인 발파방법의 개선이 요구되고 있는 바, 현 석회석 광산에서의 발파패턴을 보다 개선하여 경제적인 발파패턴을 적용하고, 그에 따른 고려해야 할 사항들을 본 논문에서 연구 하고자 한다. 따라서 국내 석회석 광산의 발파 패턴과 외국의 광산발파 패턴을 비교하고, 수치해석을 적용하여 기존의 발파 패턴에서 장약길이, 공간격, 장약량의 변화, 천공경은 102mm에서 115mm로 변화하고 장양방법을 단일장약에서 이중장약으로 변화하여 동해 쌍용자원에서 시험을 실시하였다. 연구 결과 장약길이의 20% 감소는 Power Factor를 (20%)낮게 하나, 파쇄효과는 28% 감소하고 Back Break가 (7%)이상 발생하였으며, 천공경을 115mm로 적용하고, 장약길이를 11% 감소를 위하여 이중장약을 적용하여 Power Factor를 10% 낮게 하였을 때 파쇄효과는 22.45%가 증대되었으며, 기존 동일 패턴에 Booster를 추가로 적용하였을 때 파쇄효과는 13.21% 가 증대되었고, Power Factor는 11% 가 감소되는 것을 알 수 있었다.

Frequency Analysis According to Priming Location (기폭위치에 따른 주파수 분석)

  • Son, Seok-Bum;Kang, Choo-Won;Noh, Young-Bae;Go, Chin-Surk
    • Explosives and Blasting
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    • v.29 no.2
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    • pp.51-58
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    • 2011
  • Frequency is a very important factor in discussing the effect on facilities such as precision instruments and therefore, in evaluating the effect of blasting vibration, it is necessary to identity information on frequency in addition to maximum amplitude of vibration. This study collected rock samples in gneiss area to perform an indoor rock test and to identify frequency of blasting vibration according to priming location, performed of single hole test blasting. Then the study decided dominant frequency through FFT and analysed changes according to priming locations. Consequently frequency range according to priming location is indicated top priming is distributed high range, bottom priming is distributed high range, middle priming is distributed evenly range. Frequency trend according to priming location is indicated distance increase with frequency discrease in top priming, distance increase with frequency increase in bottom priming.

Integrating the Hoek-Brown Failure Criterion into the Holmquist-Johnson-Cook Concrete Material Model to Reflect the Characteristics of Field Rock Mass in LS-DYNA Blast Modeling (LS-DYNA 발파 모델링에서 현장암반의 특성을 반영하기 위한 Hoek-Brown 파괴기준과 Holmquist-Johnson-Cook 콘크리트 재료모델의 접목)

  • Choi, Byung-Hee;Sunwoo, Choon;Jung, Yong-Bok
    • Explosives and Blasting
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    • v.38 no.3
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    • pp.15-29
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    • 2020
  • In this paper the Hoek-Brown (HB) failure criterion is integrated into the Holmquist-Johnson-Cook (HJC) concrete material model to reflect the inherent characteristics of field rock masses in LS-DYNA blast modeling. This is intended to emphasize the distinctive characteristics of field rock masses that usually have many geological discontinuities. The replacement is made only for the static strength part of the HJC material model by using a statistical curve fitting technique, and its procedure is described in detail. An example is also given to illustrate the use of the obtained HJC material model. Computation is performed for a plane strain model of a single-hole blasting on a field limestone by using the combination of the fluid-structure interaction (FSI) technique and the multi-material arbitrary Lagrangian Eulerian (MMALE) method in LS-DYNA.

A Study on the Characteristics of Blasting Vibration from Different Excavation Methods in Underground Mine (지하채굴공동에서 굴착방법에 따른 발파진동의 특성에 관한 연구)

  • Kang Choo-Won;Ryu Pog-Hyun
    • Explosives and Blasting
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    • v.24 no.1
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    • pp.1-8
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    • 2006
  • Recently, most of limestone quarries have been not mined by open-pit mining but by underground excavation to reduce environmental pollution. As a result, the size of underground galleries became bigger to maintain mass-production close to open-pit mining. However, the scale of pillars and galleries as well as the excavation methods may induce a few adverse problems for the stability of a mined gallery. In this study, the nomogram analysis and the prediction of rock damage zone induced by blasting were carried out. The testing conditions include concurrent blasting of two adjacent galleries, concurrent blasting of a transport drift and a inclined shaft, sequential blasting of two galleries, and separate blasting for each gallery. For each testing condition, blast vibration velocity was measured and analyzed. From the prediction formulas for blast vibration velocity derived in this study, the maximum depth of rock damage zone induced by blasting were also predicted.

A Study on the Application of True Maximun Vector Sum and Maximum Vector Sum In Vibration Monitoring of Blast (최대 실벡터합과 최대 벡터합의 적용성에 관한 연구)

  • 강추원;추영래;박현식
    • Explosives and Blasting
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    • v.19 no.2
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    • pp.19-26
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    • 2001
  • 국토의 효율적 활용을 위한 각종 토목.건설공사나 석재 및 골재생산 등을 위해 암반을 굴착함에 있어 다양한 산업용 화약류가 이용되고 있다. 그러나 화약의 사용으로 인해 수반되는 발파진동은 인체 및 구조물 등에 피해를 발생시켜 인근의 주민과 마찰을 일으키고 있다.본 연구에서는 발파진동속도 data를 취합하여 분석 사용함에 있어서 V, T, L 성분의 최대 실벡터합을 사용하는 경우와 최대 벡터합을 사용하는 경우를 비교하여 실제 현장 기험시 적용성을 높이고자 하였다. 진동속도는 최대 실 벡터합에 비해 최대 벡터합에 의해 구해진 진동속도의 크기가 장승근에서는 24.6%, 삼승근에서는 26.1%가 증가하는 것으로 나타났으며, 단일성분의 최대치, 최대 실벡터합, 최대 벡터합의 안전율은 1 : 1.154 : 1.359로 나타났다

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