• Title/Summary/Keyword: tunnel blasting

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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.

Determination of equivalent blasting load considering millisecond delay effect

  • Song, Zhan-Ping;Li, Shi-Hao;Wang, Jun-Bao;Sun, Zhi-Yuan;Liu, Jing;Chang, Yu-Zhen
    • Geomechanics and Engineering
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    • v.15 no.2
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    • pp.745-754
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    • 2018
  • In the analysis of the effects of rock tunnel blasting vibration on adjacent existing buildings, the model of simplified equivalent load produces higher calculation result of vibration, due to the lack of consideration of the millisecond delay effect. This paper, based on the static force equivalence principle of blasting load, proposes a new determination method of equivalent load of blasting vibration. The proposed method, based on the elastic-static force equivalence principle of stress wave, equals the blasting loads of several single blastholes in the same section of millisecond blasting to the triangle blasting load curve of the exploded equivalent elastic boundary surface. According to the attenuation law of stress wave, the attenuated equivalent triangle blasting load curve of the equivalent elastic boundary is applied on the tunnel excavation contour surface, obtaining the final applied equivalent load. Taking the millisecond delay time of different sections into account, the time-history curve of equivalent load of the whole section applied on the tunnel excavation contour surface can be obtained. Based on Sailing Tunnel with small spacing on Sanmenxia-Xichuan Expressway, an analysis on the blasting vibration response of the later and early stages of the tunnel construction is carried out through numerical simulation using the proposed equivalent load model considering millisecond delay effect and the simplified equivalent triangle load curve model respectively. The analysis of the numerical results comparing with the field monitoring ones shows that the calculation results obtained from the proposed equivalent load model are closer to the measured ones and more feasible.

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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Dynamic Influence of Tunnel Blasting on Adjacent Structures for Various RMR Values (발파에 의한 터널 굴착시 RMR값에 따른 인접구조물의 동적 영향)

  • 허재록;황의석;이봉열;김학문
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.657-664
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    • 2002
  • This study presents the influence of blasting-induced vibration on the adjacent structures in rocks of various RMR values. 3D finite element analysis was performed to simulate the behaviour of tunnel and adjacent structures during rock excavation. The blast loadings were evaluated from the blasting pressure which is depending on the type and amount of explosive charges. Influencing factors for the stability of adjacent structures and ground conditions were reviewed in terms of structural dimensions and RMR values. The stiffness and load of adjacent structures are modeled in the numerical analysis to Investigate blasting effects of the size of adjacent structures. The vibration velocity and maximum particle velocity was increase sharply when the RMR value changed from 30 to 50. The effect of particle velocity was minimized at the width of structure become 2 times of tunnel diameter.

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Blasting Impact by the Construction of an Underground Research Tunnel in KAERI (한국원자력연구소내 지하처분연구시설 건설에 따른 발파 영향)

  • Kwon Sang-Ki;Cho Won-Jin;Kim Deug-Su
    • Explosives and Blasting
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    • v.23 no.4
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    • pp.1-18
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    • 2005
  • The underground research tunnel, which is under construction in KAERI for the validation of HLW disposal system, is excavated in a granite rock by drill&blasting. In order not to disturb the operation at the research facilities including Hanara reactor by the blasting for the excavation of $6m{\times}6m$ tunnel, a test blasting at the site was performed. Using the vibration equation derived from the test blasting, it was possible to predict the vibration at different locations at KAERI and to conclude that the blasting design would meet the design criteria at the major facilities in KAERI. The noise and vibration generated by the main blasting were continuously measured. In the case of vibration, the measured values were lower than the predicted one from the vibration equation. It is, therefore, concluded that the influence of blasting work for the construction of 280m long research tunnel on the major facilities in KAERIl would be insignificant.

Evaluation of blasting vibration with center-cut methods for tunnel excavation

  • Lee, Seung-Joong;Kim, Byung-Ryeol;Choi, Sung-Oong;Kim, Nam-Soo
    • Geomechanics and Engineering
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    • v.30 no.5
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    • pp.423-435
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    • 2022
  • Ground vibration generated repeatedly in blasting tunnel excavation sites is known to be one of the major hazards induced by blasting operations. Various studies have been conducted to minimize these hazards, both theoretical and empirical methods using electronic detonator, the deck charge method, the center-cut method among others Among these various existing methods for controlling the ground vibration, in this study, we investigated the cut method. In particular, we analyzed and compared the V-cut method, which is commonly used in tunnel blasting, to the double-drilled parallel method, which has recently been introduced in tunnel excavation site. To understand the rock fragmentation efficiency as well as the ground vibration controllability of the two methods, we performed in-situ field blasting tests with both cut methods at a tunnel excavation site. Additionally, numerical analysis by FLAC3D has been executed for a better understanding of fracture propagation pattern and ground vibration generation by each cut method. Ground vibration levels, by PPVs measured in field blasting tests and PPVs estimated in numerical simulations, showed a lower value in the double-drilled parallel compared with the V-cut method, although the exact values are quite different in field measurement and numerical estimation.

On the influence survey to building by the cable Tunnel blasting works. (통신구 터널발파작업으로 인한 진동.소음이 지상주택에 미치는 영향 평가)

  • Huh Ginn;Cheon Sang Back
    • Explosives and Blasting
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    • v.11 no.1
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    • pp.5-33
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    • 1993
  • On the cable Tunnel works. Cautious blasting works were so effective and carried out. The vibration record were under 0.4cm / sec and blasting noise are under 75dB Which it was measured at the ground of Tailor House. As a result cautious blasting works under above allowable value, are not Influenced the structure of house and living. On the architechtural survey, there were some hair crack on the wall but this was not crack from recently blasting work.

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A Comparison of Operation Time between the Standard of Estimate and Actual Operations in Tunnel Blasting (터널발파시 실제 작업시간과 품셈의 비교 분석)

  • Kim, Yang-Kyun;Kim, Hyung-Mok
    • Explosives and Blasting
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    • v.33 no.3
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    • pp.14-20
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    • 2015
  • Tunnel blasting that plays the most important role in the construction of a drill & blast tunnel, shows a big difference in operation time according to various factors such as rock mass quality, tunnel dimension, machine performance, and the skill level of tunnel crews. This paper analyzes the differences between the time calculated by the standard of estimate and actual operation time based upon field investigations on blasting operation time in three tunnels of Korea. The result shows that actual blasting time is generally about 8%~16% less than the standard of estimate in cases that normal operations are performed. If the time delayed by unforeseen situations is included, however, it is presumed that the number of cases that actual operation time exceeds the standard of estimate are considerable. This study aims to help make a judgement over the appropriacy of the standard of estimate through continuous investigations on actual operation time, as well as improve the productivity of tunnel excavation.

The Study on the Verification of the Blasting Effect of Blast Stemming Material and Plug Device (발파전색재료 및 플러그 장치의 발파효과 검증 연구)

  • Ko, Young-Hun
    • Tunnel and Underground Space
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    • v.32 no.4
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    • pp.272-284
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    • 2022
  • This study conducted tunnel blasting to evaluate the blasting effect of a shear thickening fluid-based blasting stemming material and a sealed plug device under development. STF single stemming and STF stemming materials were combined with plugs to a tunnel blasting to which the SAV-Cut method was applied, and the advanced rate and fragmentation of tunnel blasting muck pile were compared when sand stemming was used. Tunnel advanced rate was evaluated using a 3D laser scanner. When the STF stemming material and STF stemming material with the plug were compared to the sand stemming material, it increased by 5.7 and 5.36%, respectively. As a result of evaluation of the fragmentation of tunnel blasting muck pile, it was the best when the STF stemming material was applied, and it decreased by about 61% compared to the case of sand stemming blasting. However, no significant improvement in blasting effect was observed with the application of plug devices.

A study on slope design at tunnel portal considering impact of blasting

  • Ji-Ung Lee;Jee-Hee Jung;Kang-Hyun Lee;SangRae Lee;Nag-Young Kim
    • Geomechanics and Engineering
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    • v.38 no.6
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    • pp.611-620
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    • 2024
  • The slope stabilization method is constructed on bedrock, but performance degradation occurs during an impact (earthquake, blasting, etc.) after construction, which may affect service life and factor of safety. In particular, the top-down method implies the possibility of damage caused by blasting vibration due to the construction procedure. However, the current blasting design only reflects damage to nearby facilities, so there is a limit in its ability to assess the damage of reinforcement methods caused by blasting vibration within the scope of influence. In this study, we aim to evaluate problems and damage levels caused by close blasting effects on rock-integrated structures, such as panel-type retaining walls, anchor-combined structures, and small nails, which are mainly constructed using the top-down method. We will also analyze factors affecting long-term performance according to changes in conditions after construction, such as tunnel excavation, to establish optimal design measures.