• Title/Summary/Keyword: Cut Blasting

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The effect of blasting patterns on cut slope stability factors (사면 안정성 요인에 대한 발파패턴의 영향)

  • Kim, Soo-Lo;Lee, Hak-Kyu;Chang, Buhm-Soo;Shin, Chang-Gun;Ahn, Sang-Ro
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.614-621
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    • 2004
  • Blasting is a technique for rock excavation: For instance, a rock cutting in a mountain side to prepare a base for a road. The blasting damage affect the rock slope stability. Therefore control blasting must be used. In this study, cutting cases of Sixty-nine rock blasts were investigated. Blasting damage patterns in rock slope and reinforcement methods are studied.

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A Case on Design and Construction of Tunnel for Under Passing an Underground Transformer Substation (지중변전실 하부통과를 위한 터널설계 및 시공사례)

  • 정동호;문상조;김선홍;이광제;석진호
    • Explosives and Blasting
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    • v.19 no.1
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    • pp.11-18
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    • 2001
  • This is a case history on design and cnostruction of tunnel for under passing an underground transformer substation. The original construction plan was cut & cover method to avoid blasting vibrations and displacements of facilities during the construction stages. But this plan was changed to tunnel because of the difficulties from construction period, cost and the required relocation site. As a results of tunnel construction, the relocation of transformer substation and replacements of transmission cables were not necessary. Therefore about 10 months of construction period and 3.5 billion wonts of construction cost were saved. Additionally, quantitative criterion for blasting was provided through the results of blasting vibration analysis.

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A Study on the Design of PLHBM (선대구경 수평보링 발파공법(PLHBM)의 설계 연구)

  • Beak, Jong-Hyun;Beak, Sang-Hyun;Han, Dong-Hun;Won, Ah-Ram;Kim, Chang-Seop
    • Explosives and Blasting
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    • v.30 no.2
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    • pp.66-76
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    • 2012
  • Blasting technology aims to maximize digging efficiency as well as minimize vibration and noise. So, it is key point of blasting technology to raise blasting effect as much as possible and reduce vibration and noise and the design of PLHBM that is the tunnel blasting method having such merit was studied in this paper. PLHBM has the excellent blasting efficiency as it drills the empty hole with high caliber of 250~1,000mm at centre cut, contributes to blasting vibration reduction effect much and can be usefully applied to tunnel blasting sites. So it is judged that it enables the development of tunnel blasting method to be advanced one more step by studying and suggesting the design method of PLHBM.

Numerical Analysis for Carinthian Cut and Cover Tunnelling Method (카린시안 터널 공법의 기준 제안을 위한 수치 해석적 연구 - 국내 고속철도 복선터널 표준 단면을 기준으로 -)

  • Roh, Byoung-Kuk;Baek, Seung-Kyu;Cha, Min-Woong
    • Explosives and Blasting
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    • v.31 no.1
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    • pp.33-40
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    • 2013
  • Carinthian cut and cover tunnelling method which combines cut & cover and NATM tunnel excavation method has increased the interest. Design and construction of arch concrete have been increased, but there is no applicable standards for arch concrete. Therefore, in this study numerical analysis was performed to propose standards for the Carinthian tunnelling method considering a variety of conditions such as ground conditions, tunnel overburden thickness, thickness of backfill, and overburden surface slope angle changes, linear regression equations derived to classify and organize a rational, economical, and safe Carinthian cut and cover tunneling method based proposed.

A Case of Blasting Vibration Reduction in the Tunnel Construction under a Residential Area (주거지역 터널공사에서의 발파진동 저감사례)

  • Kang, Jin-Ook;Lee, Hyun-Koo;Lee, Myong-Choul
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.175-180
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    • 2007
  • This paper presents a case study on blasting vibration reduction in NATM(New Australian Tunnelling Method) tunnel construction carried out under a congested residential area. In NATM tunnel constructions, blasting is an essential process, thus vibration phenomenon is inevitable. Therefore, the vibration reduction was tried to avoid expected complaints from the public living in the area. Test blastings were performed to get the constants for an estimation formula of vibration velocity. Then the influence area was approximated using the estimation formula, and construction methods for the vibration reduction were sought based on the results.

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Study of the Blast Pattern to Improve the Effect on Fragmentation in a Small Sized Silica Mine in Korea (국내 소규모 규석광산의 파쇄효과 향상을 위한 발파패턴 연구)

  • Yang, Hyung-Sik;Kim, Jeong-Gyu;Ko, Young-Hun;Kim, Seung-Jun;Mun, Hee-Sook;Kim, Won-Beom;Jang, Hyong-Doo
    • Explosives and Blasting
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    • v.30 no.1
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    • pp.52-59
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    • 2012
  • Fragmentation is one factor to affect productivity and economic efficiency of mine. Authors investigate the blasting pattern and improve it step by step while observing the fragmentation results. Final pattern was suggested and the fragmentation improved 24 % compared to traditional pattern, with 50 % is passing rate.

Study on the measurement of blasting vibration response in construction a subway station at East gate of cultural treasure (지하철건설에 따른 문화재 보호와 동대문역사시공 보고서(1))

  • Choi, Sang-Yol;Ree, Soo-Book;Huh, Ginn;Chai, Soo-Yun
    • Journal of the Korean Professional Engineers Association
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    • v.17 no.3
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    • pp.32-49
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    • 1984
  • The East gate station area is 205M long and 24m deep which is located 13 meter in front of cultural treasure east gate. The area to be excavated by blasting is composed of granite rocks from 10M depth to 25M. Surface earth extends to up 10M depth. This job site has in involves heavy traffic congestion such as over 10,000 cars passing in rush hour where clossing No 1 lint of subway running 3 minitues head way. This east gate station construction is to be executed for the provent of the setting down of underground level and blasting vibration effects to cultural treasure east gate. Therefore, the caltural treasure committee approved this execution subject to the following condition. 1. Subway gelogical foundation and measured natural frequency 2. Execution of water tight wall 3. Sellection and test of damping material for wall and under rail 4. Measurement of monitoring system during the execution 5. Measurement of histogram system The above two projects was carried out by Dr. Kwang team in KAIST and prof, Han in Hanyang University under accadamic study contract. In the blasting work, for the pourpose of reduced vibration and low explosion velocity such as CCR, Kovex slurry. The 2nd, used electrical caps shall be delay cap and M/S caps in multi delay. The 3rd, drilling pattern is bench cut in open cut and applied control blasting in tunnelling and also shall drill anti-vibration holes as line drilling.

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Dynamical Study on the Blasting with One-Free-Face to Utilize AN-FO Explosives (초유폭약류(硝油爆藥類)를 활용(活用)한 단일자유면발파(單一自由面發破)의 역학적(力學的) 연구(硏究))

  • Huh, Ginn
    • Economic and Environmental Geology
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    • v.5 no.4
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    • pp.187-209
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    • 1972
  • Drilling position is one of the most important factors affecting on the blasting effects. There has been many reports on several blasting factors of burn-cut by Messrs. Brown and Cook, but in this study the author tried to compare drilling positions of burn-cut to pyramid-cut, and also to correlate burn-cut effects of drilling patterns, not being dealt by Prof. Ito in his theory, which emphasized on dynamical stress analysis between explosion and free face. According to former theories, there break out additional tensile stress reflected at the free face supplemented to primary compressive stress on the blasting with one-free-face. But with these experimented new drilling patterns of burn-cut, more free faces and nearer distance of each drilling holes make blasting effects greater than any other methods. To promote the above explosive effect rationary, it has to be considered two important categories under-mentioned. First, unloaded hole in the key holes should be drilled in wider diameter possibly so that it breaks out greater stress relief. Second, key holes possibly should have closer distances each other to result clean blasting. These two important factors derived from experiments with, theories of that the larger the dia of the unloaded hole, it can be allowed wider secondary free faces and closes distances of each holes make more developed stress relief, between loaded and unloaded holes. It was suggested that most ideal distance between holes is about 4 clearance in U. S. A., but the author, according to the experiments, it results that the less distance allow, the more effective blasting with increased broken rock volume and longer drifted length can be accomplished. Developed large hole burn-cut method aimed to increase drifting length technically under the above considerations, and progressive success resulted to achieve maximum 7 blasting cycles per day with 3.1m drifting length per cycle. This achievement originated high-speed-drifting works, and it was also proven that application of Metallic AN-FO on large hole burn-cut method overcomes resistance of one-free-face. AN-FO which was favored with low price and safety handling is the mixture of the fertilizer or industrial Ammonium-Nitrate and fuel oil, and it is also experienced that it shows insensible property before the initiation, but once it is initiated by the booster, it has equal explosive power of Ammonium Nitrate Explosives (ANE). There was many reports about AN-FO. On AN-FO mixing ratio, according to these experiments, prowdered AN-FO, 93.5 : 6.5 and prilled AN-FO 94 : 6, are the best ratios. Detonation, shock, and friction sensities are all more insensitive than any other explosives. Residual gas is not toxic, too. On initation and propagation of the detonation test, prilled AN-FO is more effective than powered AN-FO. AN-FO has the best explosion power at 7 days elapsed after it has mixed. While AN-FO was used at open pit in past years prior to other conditions, the author developed new improved explosives, Metallic AN-FO and Underwater explosive, based on the experiments of these fundmental characteristics by study on its usage utilizing AN-FO. Metallic AN-FO is the mixture of AN-FO and Al, Fe-Si powder, and Underwater explosive is made from usual explosive and AN-FO. The explanations about them are described in the other paper. In this study, it is confirmed that the blasting effects of utilizing AN-FO explosives are very good.

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Comparison of Blast Fragmentation Efficiencies from Conventional Bench and Double Air Deck Charge Blast Methods in Limestone Mine (석회석 광산에서 기존 일반발파와 이중분상 Air Deck 발파공법의 비교연구)

  • Kang, Dae-Woo;Hur, Won-Ho;Yang, Kook-Jung;Park, Dong-Chul
    • Explosives and Blasting
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    • v.29 no.2
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    • pp.13-31
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    • 2011
  • Air deck charge blast methods have been applied to improve the fragmentation in open cut bench blastings for mining developments. However, during large scale bench blasting operations, there exist some problems such as boulder productions due to explosive charge concentration. Especially, in case of lime stone mining, when air deck method is applied, there has been unintentionally concentrated on charging because the inside holes are often broken by erosion and decomposition. In this study, compared with general blasting, air deck blasting has been focused in lime stone mining. In other to maximize its efficiency, inside hole was examined by endoscope in advance and deck charge using air tube was applied to the section in which concentration might be taken place. Blasting efficiency, fragmentation, charging reduction rate, and total working hours (from charging to blasting) were the main object for comparing, and as a result, air deck was more efficient then the general blasting in all aspects except total working hours.