• Title/Summary/Keyword: Tunnel blasting design

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Tunnel Blasting Design with Equations Obtained from Borehole and Crater Blasting (시추공 및 누두공 발파자료의 터널설계 적용)

  • 양형식;임성식;김원범
    • Journal of the Korean Geotechnical Society
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    • v.19 no.5
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    • pp.327-333
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    • 2003
  • Characteristics of vibration propagation of borehole blasting were analyzed with 578 borehole vibration data obtained from 23 sites which were used in tunnel and underground space design, and 221 tunnel vibration data fron 4 sites of tunnel under construction. Analysis results on the damping of vibration velocity show that site factors in borehole blasting were higher than those in tunnel blasting. And the critical charge calculated from regression equations at large scaled distance was lower in borehole blasting. Dominant frequency was in the range of 30∼60Hz for the borehole blasting and 60∼90Hz for the tunnel blasting. As a conclusion, the borehole blasting data should not be used on the tunnel blasting design without careful statistical analysis.

Effect of Rock Damage Induced by Blasting on Tunnel Stability (발파굴착의 암반손상이 터널안정성에 미치는 영향분석)

  • Lee, In-Mo;Yoon, Hyun-Jin;Kim, Dong-Hyun;Lee, Sang-Don;Park, Bong-Ki
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.681-688
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    • 2003
  • Rock damage induced by blasting can not be avoided during tunnel construction and may affect tunnel stability. But the mutual interaction between tunnel blasting design and tunnel stability design is generally not considered. Therefore this study propose a methodology to take into considration the results of the blasting damage in tunnel stability design. Rock damage is evaluated by dynamic numerical analysis for the most common blasting pattern adopted in road tunnel. Damage zone is determined by using the continuum damage model which is expressed as a function of volumetric strain. And the damage effect is taken into account by the damaged rock stiffness and the damaged failure criteria in tunnel stability assessment. The extend of plastic zone and deformation increase compared to the case of not considering blast-induced rock damage.

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Design guide for full-face blasting in highway tunnel (고속도로 터널에 대한 전단면 발파 설계방안 연구)

  • Lee, Sang-Don;Choi, Hae-Moon;Lee, Hyun-Koo;Ryu, Chang-Ha
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.930-937
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    • 2004
  • In tunnel blasting, rock damage and overbreak at excavation limits are strongly related to stability of the tunnel and cost for rock support, and also affect to maintenance after tunnel construction. In this study, many field tests and measurements have been carried out in highway tunnels so that discordance between blast design and practical production blasting could be settled and actual methods of over break control could be proposed through the understanding of the problems in existing blasting patterns. Test blasting in tunnel was carried out many times in two tunnel sites. Also, long hole blasting longer than existing blasting pattern was executed for good grade of rock mass whose RMR value is more than 60. Using the results of test blasting, new standard blasting patterns for two lane tunnel were proposed. As a result of profile measurement after blasting, drilling is a major factor of overbreak. And then the methods for minimizing overbreak were adapted in new blasting patterns.

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A Case on Excavation Plan and Design of Adjacent Railroad Tunnel (근접 철도터널의 굴착계획 및 설계 사례)

  • 김선홍;정동호;석진호;정건웅;서성호
    • Explosives and Blasting
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    • v.20 no.3
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    • pp.59-71
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    • 2002
  • The points of this design case are the planning and excavation method of a new double-tracked railroad tunnel which is approx. 11∼22 meters apart from existing single-tracked railroad tunnel. For the optimum excavation method some needs are required in design stage, such as the reduction of noise and vibration, public resentment, damage of buildings and construction costs. Hence the estimation and application of allowable noise and vibration criterion is important. The ground coefficient (K, n) of this site is determined by field trial blasting. The excavation method is chosen to satisfy the allowable noise and vibration criterion. In addition, in order to ensure the stability of existing single-tracked railroad tunnel, the instrumentation of maintenance level is accompanied during the construction stage. As a result of this design condition, central diaphragm excavation with line drilling and pre-large hole boring blasting is applied to the area within 15 meters apart from existing tunnel. And above 15 meters apart, pre-large hole boring blasting is designed.

Development of Automated Pattern Generation Method for Tunnel Blasting (터널발파설계 자동화를 위한 발파패턴 설계식 개발)

  • Choi Yong-Kun
    • Explosives and Blasting
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    • v.23 no.4
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    • pp.19-29
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    • 2005
  • Blasting design methods applied in Korea were originally made for foreign rock conditions and blasting environments. Therefore, it has not been fully fitted to the Korean rock renditions. Since 1998, several studies for the automated pattern design of tunnel blasting have been carried out. As the result, a new blasting design method which can settle the problems was developed. Through it is more complex than prior method, it call provide a variety of advantages for us. Through the method, it is possible to vary charge weight according to the changing advance. It ran also be applied to the various design for contour holes. In this study, the newly developed method is introduced.

Blasting Design for Large Shaft in Urban Area Considering Noise and Vibration -Singapore Transmission Cable Tunnel EW2- (소음 및 진동을 고려한 도심지 내 대단면 수직구 발파설계 사례 -싱가포르 Transmission Cable Tunnel EW2 공구-)

  • Kim, Julie;Lee, Hyo;Kim, Dave;Ko, Tae-Young;Lee, Simon
    • Explosives and Blasting
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    • v.31 no.1
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    • pp.55-63
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    • 2013
  • With increasing needs in power, Singapore is requiring stronger power transmission. Singapore Transmission Cable Tunnel is underground tunnel for transmission system installation such as 400 kV cable. This Transmission Cable Tunnel is 35 km long in total. The North-South Transmission Cable Tunnel is 18.5 km long and there is a total of three (3) contracts; NS1, NS2 and NS3 in respect of the design and construction. The East-West Transmission Cable Tunnel is 16.5 km long, and also there is a total of three (3) contracts; EW1, EW2 and EW3. Among of them, SK E&C has been awarded and operating contract EW2 and NS2. In scope of works, each contract has 3 to 4 shafts which connect aboveground and underground high volt cable and those shafts are used as TBM launching shafts during construction. Transmission Cable Tunnel is undercrossing middle of Singapore and most of shafts are located in urban area. Thus, optimal blasting design satisfying high blasting efficiency as well as blasting vibration limit of Singapore is highly required. Blasting design for large shaft of Singapore Transmission Cable Tunnel follows blasting vibration limits in Singapore and reflects our blasting engineering skills. With Singapore Transmission Cable Tunnel Contract EW2, it is expected that our excellent blasting engineering and performance skills can be delivered to the world.

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.

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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Numerical Modelling of Tunnel Blasting (터널발파의 수치해석적 모델링)

  • 이인모;최종원;김상균;김동현
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03b
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    • pp.133-140
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    • 2000
  • Drilling and blasting method for excavating rock mass is generally used in underground construction; but this technique has some shortcomings. For instance, rock mass damage is inevitable during drilling and blasting, and blast-induced vibration frequently causes some problems. Until now, field measurement method is used to predict the overbreak and vibration; but it has many limitations. Therefore, numerical analysis method is needed to overcome such limitations, and to estimate and predict damage and vibration due to tunnel blasting in the design stage. In this study, damage zone of rock mass due to stoping and contour blasting is compared based on standard tunnel blasting pattern, and the propriety of the standard tunnel blasting pattern is estimated. Then, blasting pattern is optimized so that the damage zone due to sloping blasting with reduced charge is consistent with that due to contour blasting.

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