• Title/Summary/Keyword: 발파버력

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The effect of material behavior of blasted muck on the impact force applied on a protector (발파 버력의 재료거동이 프로텍터에 작용하는 충격하중에 미치는 영향)

  • Kim, Woong-Ku;Jin, Byeong-Moo;Baek, Ki-Hyun;Seo, Kyoung-Won
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.13 no.3
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    • pp.261-275
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    • 2011
  • To maintain the traffic flow during tunnel expansion, cars must be protected from falling rocks during excavation and to do so, a protector has to be installed inside the tunnel before beginning the excavation. In Korea, tunnel expansion by blasting rather than by mechanical excavation has been widely achieved. For this reason, a series of numerical analysis were performed to analyze the characteristics of impact load according to material behaviour of blasted rock by using Explicit FEA program. From the numerical results, it is found that the impact loads when rock is assumed as an elastic-plastic material appear to be only 7~12% compared with that when it is elastic.

A Case Study of Applying Electronic Detonator in Limestone Quarry (석회석 광산에서 전자뇌관의 적용성에 관한 연구)

  • ;;;Dave Kay
    • Explosives and Blasting
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    • v.22 no.2
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    • pp.1-11
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    • 2004
  • 일반적으로 국내 석회석 광산에서의 발파는 20ms나 25ms 시차를 가지는 지발발파로 시행되어지고 있다. 국외에서는 전자뇌관을 사용하여 암반의 지질학적인 특성에 따라 지발 시차를 사용자의 현장에 따라 선정하여, 주변 보안 물건에 따른 진동 및 소음을 경감하면서, 1회 발파의 생산량을 증대할 수 있으며, 2차 파쇄 비용 및 적재비용을 절감하는 최적의 시차를 적용하여 발파 규모를 줄이지 않는 발파패턴을 적용하고 있다. 본 연구는 해외에서 사용되고 있는 전자뇌관을 국내 현장 석회석 광산(단양)에 적용함으로 최적지연시차를 찾아내는 방법과 초시의 오차에 따른 문제점과 향후 국내 적용성을 판단하고자 하였다. 대규모 석회석 광산을 대상으로 최적시차를 판단하고자 동일 패턴에서 시차를 6ms ~ 30ms로 시험발파를 시행하여 4가지 요소 발파진동속도, 주 주파수특성, 파쇄입도, 암석 이동 및 버력의 상태를 분석하여 각 시차에 따른 배점을 두어, 당 현장에 요구되는 개별 가중치를 선정하여 분석하였다. 분석 결과 당 현장에서의 발파결과에 따른 요소별 가중치를 발파진동속도(20), 주 주파수 특성(20), 파쇄입도(40), 암석 이동(10) 및 버력의 상태(10)로 하여 분석한 결과 15ms가 최적시차로 나타냈다. 향후 각 현장에 적합한 요소별 가중치를 선정하여 현장별 최적시차를 도출한다면 최적의 발파효과를 있을 것으로 판단된다.

A Study on the Development of the Rock Blastability Classification and the Methods for Minimizing Overbreak in Tunnel (터널 굴착면 여굴 최소화를 위한 발파암 분류(안) 및 공법 개발 연구)

  • 이태노;김동현;서영화
    • Explosives and Blasting
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    • v.20 no.3
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    • pp.25-38
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    • 2002
  • 터널 굴착선 여굴(Overbreak)은 발파공법에 의한 괄착 중에 필연적으로 발생하는 현상으로서 숏크리트, 라이닝 등의 보강비 추가 발생과 버력 처리량의 증대로 공기 및 공사비를 증가시키는 주요한 요인으로 작용한다. 또한 터널 굴착선 암반의 손상으로 균열층이 형성되거나 부석이 발생하여 안전문제를 야기시키기도 한다. 이러한 여굴 발생은 천공오차, 발파패턴의 오류, 잘못된 화약선정, 불규칙한 암반 특성 등에 그 원인이 있으나, 지금까지 터널 여굴은 천공 및 발파기술에 의해 좌우된다라는 인식이 대부분이었다. 그러나 여굴 발생에 중요한 원인으로 터널 굴착선 암반의 특성과 이에 적합한 발파패턴 및 화약류를 들 수 있다. 본 연구는 여굴 발생에 영향을 미치는 암반상태를 파악하기 위해서 터널 굴착선 주변암반의 균열정도, 강도, 불연속면의 간격, 방향, 간극, 충전물 상태 등의 6가지 요소를 이용하여 암반을 분류하는 발파암 분류법(BI)을 새로 제안하였고, 이 분류에 따라 외곽 공의 간격과 장약밀도를 달리 하는 발파패턴을 정립하였다. 또한 화약의 순폭도와 Air Deck 효과를 이용하여 장약밀도를 조절할 수 있는 N.D.C(New Deck Charge) 발파공법을 개발함으로써 여굴을 최소화할 수 있었다.

The Improvement of Tunnel Construction Cost Standards Considering the Site Conditions in Korea (현장실태를 고려한 국내 터널공사 공사비산정기준 개선)

  • Ahn, Bang-Ryul;Lee, Han-Soo;Oh, Jae-Hoon;Song, Tae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.8
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    • pp.26-35
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    • 2020
  • Tunnel construction is an important part of Korean public construction projects. Although the development of various equipment and technologies has led to advances in tunnel construction methods that are implemented on sites, the cost standards related to such works do not yet reflect the realities of the construction sites. A literature review and site surveys were conducted to suggest reasonable cost standards for tunnel work that reflects the realities of the field. First, each item in the cost standards for tunnel work, as established in the Construction Standard Production Rates, were analyzed. The results were compared with the actual costs implemented on tunnel projects. The key items analyzed included those regarding the work cycle time, such as rock classification, profiling survey, drilling speed, and muck-disposal processing equipment combination, as well as the number of people put to tunneling work. Based on the site survey results, improved estimates regarding the cycle time per one tunnel drilling blast, drilling speed of the machine, muck disposal processing equipment combination, and the number of people put to tunneling work were suggested. This study suggests the cost standards that reflect the realities of tunneling sites. The results are expected to help ensure adequate costs for tunnel construction projects.

A study on the excavation cycle by the drill-and-blast method for a room-and-pillar underground structure (주방식 지하구조물의 발파 굴착공정 분석 연구)

  • Lee, Chul-Ho;Hyun, Young-Hwan;Hwang, Je-Don;Choi, Soon-Wook;Kang, Tae-Ho;Chang, Soo-Ho
    • 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.

Case of assembly process review and improvement for mega-diameter slurry shield TBM through the launching area (발진부지를 이용한 초대구경 이수식 쉴드TBM 조립공정 검토 및 개선 사례)

  • Park, Jinsoo;Jun, Samsu
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.6
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    • pp.637-658
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    • 2022
  • TBM tunnel is simple with the iterative process of excavating the ground, building a segment ring-build, and backfilling. Drill & Blast, a conventional tunnel construction method, is more complicated than the TBM tunnel and has some restrictions because it repeats the inspection, drilling, charging, blasting, ventilation, muck treatment, and installation of support materials. However, the preparation work for excavation requires time and cost based on a very detailed plan compared to Drill & Blasting, which reinforces the ground and forms a tunnel after the formation of tunnel portal. This is because the TBM equipment for excavating the target ground determines the success or failure of the construction. If the TBM, an expensive order-made equipment, is incorrectly configured at the assembly stage, it becomes difficult to excavate from the initial stage as well as the main excavation stage. When the assembled shield TBM equipment is dismantled again, and a situation of re-assembly occurs, it is difficult throughout the construction period due to economic loss as well as time. Therefore, in this study, the layout and plan of the site and the assembly process for each major part of the TBM equipment were reviewed for the assembly of slurry shield TBM to construct the largest diameter road tunnel in domestic passing through the Han River and minimized interference with other processes and the efficiency of cutter head assembly and transport were analyzed and improved to suit the site conditions.