• 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.

• Tunnel and Underground Space
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• v.13 no.4
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• pp.316-320
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• 2003

This study is to evaluate an irregular drill-hole depth having an effect on the blast vibration. The relationship between a peak particle velocity and a cube root scaled distance with respect to three drill-hole depths with 2.1m, 2.3m and 2.4m are compared and analyzed using a numerical regression analysis. According to the results, the deeper a drill-hole depth is the larger a peak particle velocity is. It is suggested that a drill-hole depth is proportional to a peak particle velocity at the same scaled distance. Therefore, a regular drill-hole should be carried out in order that the blast vibration velocity of a fixed range under a allowable vibration velocity is maintained.

• Explosives and Blasting
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• v.24 no.1
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• pp.57-62
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• 2006

The typical blasting method adopted in Pasir Coal Mine is a surface blasting technique with a single free face. It means that there is only one free face, which is usually the ground surface. This kind of blasting method is easy to use but inevitably causes enormous ground vibrations, which, in turn, can affect the stability of the slopes comprising the various boundaries of the open pit mine. In addition, the method also has the problem of lowering the blast efficiency compared to other methods such as bench blasting methods or ones with more than two free faces. In this respect, a project was launched to develop a new blasting method that is suitable for controling the ground vibration and enhancing the blast efficiency. As a part of the project, authors investigated the current blasting method as well as the overall pit developing process in the mine, and established some important guidelines that should be observed during the whole development process. This paper presents the details of the typical blasting pattern and the pit developing method in the mine, and suggests the guidelines determined from the results of the observations.

• Explosives and Blasting
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• v.29 no.2
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• pp.51-58
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• 2011

Frequency is a very important factor in discussing the effect on facilities such as precision instruments and therefore, in evaluating the effect of blasting vibration, it is necessary to identity information on frequency in addition to maximum amplitude of vibration. This study collected rock samples in gneiss area to perform an indoor rock test and to identify frequency of blasting vibration according to priming location, performed of single hole test blasting. Then the study decided dominant frequency through FFT and analysed changes according to priming locations. Consequently frequency range according to priming location is indicated top priming is distributed high range, bottom priming is distributed high range, middle priming is distributed evenly range. Frequency trend according to priming location is indicated distance increase with frequency discrease in top priming, distance increase with frequency increase in bottom priming.

• Journal of the Korean Geotechnical Society
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• v.40 no.2
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• pp.7-17
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• 2024

Vibrations were measured at the surface of a GTX-A site to assess the impact of blasting on underground tunneling. A numerical analysis was conducted using the same ground and blast conditions as those at the site, accompanied by a comparative analysis of other GTX-A sites. This analysis determined the maximum vibration velocity at regular intervals directly above the blasting point at each site. The results were compared with domestic and international vibration standards to establish the vibration measurement range. The specified vibration measurement locations in domestic regulations—"measuring from the closest part of the structure's foundation to the blasting source, and if conditions make it impossible, measuring from the nearest surface to it"—were evaluated. Furthermore, this study underscores the significance of considering the tunnel drilling depth and soil conditions when selecting a vibration measurement location.

• Tunnel and Underground Space
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• v.28 no.5
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• pp.457-475
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• 2018

For increase of reality in numerical analysis, a blasting vibration waveform obtained from field blast operations has been directly used for input parameters of dynamic analysis in the form of vibration velocity. A numerical model was built considering the geological characteristics of underground limestone opening as well as the mining stages in this opening, and the effect of blast operations on stability of underground limestone opening was investigated by dynamic numerical analysis. The adequacy of applying the real vibration waveform to dynamic analysis has been approved from the preliminary analysis, and the dynamic numerical analysis results show that the continuous mining operation can cause the collapse of roof in openings and the active yield zone around openings. Therefore, the additional reinforcements should be applied for ensuring the stability of underground limestone openings.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.185-192
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• 2012

The objective of this study is to present and verify a method for evaluating the fundamental period of a rockfill dam using artificially generated vibration from a blasting event. In this study, the artificial blasting vibration tests were carried out at the site adjacent to the existing Seongdeok Dam for the first time in Korea. The artificial vibrations were induced by 4 different types of blasting with the various depths of blasting boreholes and the various explosive charge weight. During the tests, the accelerations time histories were recorded at the crest of the dam. In this acceleration history, only free vibration decay part following the main vibration event was extracted and it was analyzed by frequency domain analysis using Fast Fourier Transform (FFT). From the results of FFT, the fundamental period of the target dam was evaluated. It is found that the effect of different blasting types on the fundamental period of the target dam is negligible and the fundamental period of the target dam can be consistently obtained by blasting vibration tests. Furthermore, it is found that the period of the target dam calculated by the method using blasting vibration test is similar to that obtained by the method of previous researchers using the real earthquake records. Therefore, in case that the earthquake record is not available, the fundamental period of a rockfill dam can be reasonably evaluated if blasting vibration test is allowed at the site adjacent to the dam.

• Explosives and Blasting
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• v.29 no.2
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• pp.32-42
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• 2011

For blasting vibration analysis, there are mostly two methods, firstly, far field vibration analysis to estimate limit of building damage, secondly, near field subterranean vibration analysis to estimate rock damage and subterranean structure facilities. The former has been mainly used in our country and aboard, the latter is mostly analysed by using Homberg's model. In this model, basic input data are acquired in far field surface vibration. But in the consideration of the results of being conducted in this area over the past few decade, it is required that Homberg's model is modified. For the purpose of this, measurements of near field vibration were first conducted in our country. But it was only proposed the measurement method and the method of analysis or prediction was not suggested. Accordingly, in this paper, measurements of near field subterranean vibration were conducted and the method of analysis or prediction of near field subterranean vibration would be suggested.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.197-208
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• 2022

The existence of shallow bedrock and the desire to use underground space necessitate the use of blasting methods. The standard blasting method under water after drilling is associated with certain technical difficulties, including reduced detonation power, the use of a fixed charge per delay, and decoupling. However, there is no blasting method to replace the existing blasting method. In this paper, a dry hole charged with ANFO blasting is assessed while employing a dry hole pumping system to remove water from the drill borehole. Additional standard blasting is also utilized to compare the blasting performances of the two methods. The least-squares linear regression method is adopted to analyze the blasting vibration velocity quantitatively using the measured vibration velocity for each blasting method and the vibration velocity model as a function of the scaled distance. The results show that the dry hole charged with ANFO blasting will lead to greater damping of the blasting vibration, more energy dissipation to crush the surrounding rock, and closer distances for the allowable velocity of the blasting vibration. Also, standard blasting shows much longer influencing distances and a wider range of the blasting pattern. The pilot test confirms the blasting efficiency of dry hole charged with ANFO blasting.

• Journal of KSNVE
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• v.7 no.2
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• pp.189-198
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• 1997

현재 행해지고 있는 환경 기술자에 의한 공해성 환경영향평가와 택지조성사업, 터널공사, 각종 도로공사, 건물 해체 작업시 이루어지는 발파 기술자에 의한 발파 영향평가 및 토목. 건축 기술자들에 의해 시공현장에서 주로 행해지는 기타 건설 소음. 진동 영향평가는 진단 개념에서 볼 때, 측정목적과 측정대상에 따른 각종 기준적용과 측정방법 및 분석절차 상에서 몇가지 문제점을 안고 있으며 실제 현장 계측시에도 측정위치 선정, 센서부착 방법, 측정 횟수 및 측정 모드 선정 등에서 상당한 오류를 범하는 것을 종종 볼 수 있다. 따라서 본 연구에서는 각종 소음. 진동 영향평가의 현실태 및 피해 대상물에 대한 진단시 우려되는 기준 적용, 측정 및 분석상의 문제점들을 조사하고 개선방안을 살펴봄으로써 소음. 진동 피해진단 기술을 정립하고 향후과제에 대해 논의하고자 한다.