• Tunnel and Underground Space
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• v.16 no.2 s.61
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• pp.179-188
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• 2006

The vibration or/and noise generated by blast operations might cause not only structural damage to properties but mentally also to humans and animals. For that reason, maximum permitted vibration and noise levels are set by sensitivities of structures and they are used for the management of blast vibration. It is known that the fish lived in water are more sensitive to vibration than land animals, and thus the adverse impact of the blasting on fish farms should be very concerned. This study investigated the vibration and noise levels at a large eel farm located some 840 meters of the blasting site through the large real-scale experiments of blastings, prior to conducting the actual blasting. As a result, it was found that the noise met the requirement to be within maximum permitted level, while the ground vibration exceeded the permitted vibration. Accordingly, the impact of the excess vibration was investigated by an existing empirical method and verified by a new three dimensional numerical analysis. In this study, such an inspection process was briefly described, and a method was suggested for the examination of possible adverse effects from blasting on vibration-sensitive structures like the eel farm. The study also introduced a design method that controls the blast effects - ground vibration and noise.

• 기계와재료
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• v.21 no.4
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• pp.96-105
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• 2010

도로 및 철도는 차량의 고속화와 신속한 물류의 유통을 위해 직선 및 수평화가 절실하게 요구되며, 국내 건설구간의 약 50~70%가 산악지형으로서 터널공사가 필수적으로 요구된다. 국내터널굴착은 주로 발파에 의한 NATM(New Austrian Tunneling Method)으로 공사가 이루어지고 있으나, 굴착효율이 낮으며 안전사고의 위험성이 높다. 해외에서는 급속한 시공을 위하여 TBM(Tunnel Boring Machine)의 적용 사례가 증가하고 있다. 그러나 국내에는 TBM에 대한 연구가 전무한 상태이고, TBM 터널의 설계 시공 기술과 경험이 미흡하다. 최근 대도시의 지하터널과 장대터널의 수요가 증대되어 TBM터널시공 기술과 TBM장비의 국산화가 절실하게 요구되고 있다. 본고에서는 국내외 주요 TBM 시공현황과 전망을 정리하여 TBM 터널 기술의 확보가 매우 시급함을 상기시키고자 하였다.

• Explosives and Blasting
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• v.31 no.1
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• pp.64-75
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• 2013

This case study deals with an excavation blasting carried out at "Sooseo-Pyeongtek ${\bigcirc}$-${\bigcirc}$ section construction site" in the vicinity of residential area. Originally, the sequential blasting (multi-stage blasting) using electric detonators was planed in this area. However, there was a concern that the sequential blasting method could increase the construction cost by delaying the construction period due to possible complaints from local residents. As an alternative, electronic deck blasting technique was taken in order to meet the ground vibration regulation (0.2cm/s, in apartment area) and to keep the construction schedule. The performance of the electronic deck charge blasting was two times better than the sequential blasting with electric detonators and the level of ground vibration was also within the regulatory value (0.2cm/s). In particular, it was shown that the use of electronic detonater eDevII, which was developed for tunnel, could provide more convenient and electrically safer working condition.

• Tunnel and Underground Space
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• v.9 no.1
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• pp.72-77
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• 1999

New criteria to evaluate blasting damage to structure is proposed considering environmental caused daily deformation of cracks in structures. Results from 3 brick houses in fishing village shows that more than 10 times higher vibration level than design criteria of 0.5 kine is required to cause structural damage.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.157-173
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• 2023

Although this site is designed with a non-vibration excavation method for a section of 265 m, there are concerns about decline of constructability and economic feasibility. For this reason, the low-vibration electronic detonator blasting method was suggested. To evaluate the applicability of the low-vibration electronic detonator blasting method, the damage range of blasting vibration of low-vibration electronic detonator blasting applied just before the site (suggestion I) and low-vibration electronic detonator blasting constructed close range the subway like this site (suggestion II) was analyzed. As a result of comparing the blasting vibration damage ranges of the two suggestions, the damage range of suggestion II was calculated more conservatively. Considering the specificity of the close range of this site, suggestion II was selected for design change for safer construction. As a result, it is predicted that there will be no damage to the structure even if the 72 m section out of the non-vibration excavation 265 m section is changed to the Low-vibration electronic detonator blasting. And it is evaluated that high economic benefits can be obtained because the total expected excavation period can be reduced by 144 days from 662.5 days.

• Explosives and Blasting
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• v.26 no.2
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• pp.20-28
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• 2008

In the design stage of a tunnel, the wall convergence is commonly estimated through an elasto-plastic analysis of the tunnel, which has been a topic drawing many researcher's attention so far. Despite its importance, however, the elasto-plastic behavior of a circular tunnel excavated in a generalized Hoek-Brown rockmass is still poorly understood. In this study, a simple munerical method based on Lee & Pietruszczak (2008) for the elasto-plastic analysis of a circular tunnel surrounded by reinforced annulus is proposed. It is assumed that the tunnel is excavated in a strain-softening rockmass obeying the generalized Hoek-Brown failure condition. The commercial code FLAC is used for the verification of the proposed method. The influence of the Hoek-Brown strength parameter a and the thickness of the reinforcement annulus on the elasto-plastic behavior around the tunnel was discussed by conducting some example analyses. The results show that the influence of these two parameters on the distribution of stresses and displacements is substantial.

• Tunnel and Underground Space
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• v.24 no.1
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• pp.97-109
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• 2014

In order to identify the characteristics of the propagation depending on delay time (20, 25 ms) and priming location (top priming, middle priming, bottom priming), test blasts were carried out a total of 4 times using different spacing, burden, drilling length, charge per delay and was derived the formula to predict blast vibration. This study investigated the characteristics of vibration by analysis of the nomogram and prediction of Peak Particle Velocity (PPV) from delay time and priming location by the formula to predict ground vibration. And it analyzed the trends of vibration increase by standards charge 0.5, 1.6, 5, 15 kg. Standards charge is "Blasting design and construction guidelines to road construction" by the Ministry of Land, Infrastructure and Transport. Depending on the charge in favor of vibration control method is proposed. Thus, when the design was to be used as a variable.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.475-480
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• 2000

The propagation of blast vibration and the damping characteristics depend on both the mechanical properties of rock mass and weight charge. In this study, the characteristics of propagation and damping were analyzed by FLAC. The construction site was the second Kwang-ju circulating road. Taguchi method which is one of experimental design methods was used for determination of input data and parameter levels. The results showed that rock density was the most dominant of variables being concerned in this study, which affect the propagation of blast vibration.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.486-491
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• 2000

Blasting vibrations velocity had been used to design blasting pattern and predict damage-possibility of structures. As vibration levels are currently required to estimate the damage concerning human-body and livestock, so measured vibration velocities must be transformed into vibration levels. In this study, the digital filter program was developed to transform measured data into vibration levels. Simple harmonic vibrations and measured data obtain by Blastmate series (Instantel Inc.) were applied to the digital filter program. As a result, simple harmonic vibrations and measured data were successfully transformed into vibration levels using the developed program. Measured data from any instrument with ASCII output-function will similarly be transformed into level units.

• Tunnel and Underground Space
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• v.15 no.5 s.58
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• pp.338-343
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• 2005

This study analysed response spectrum using the observed ground motion from the mine blasting and, then compared the results to the seismic design response spectra applied domestic nuclear power plants. The results showed that the resultant response spectra above 20 Hz revealed higher values than the design response spectra and those below 20 Hz revealed much lower values. These facts suggest that the analysis of response spectrum should be applied to the analysis of impacts to frequency dependent structures in addition to the analysis of peak values of ground motions.