• Explosives and Blasting
• /
• v.34 no.3
• /
• pp.21-26
• /
• 2016

In case of urban blasting works at near neighbors, the size of one blasting should be minimized to reduce the vibration and noise. However, the complaints is not decreased due to increased numbers of blasting per day so that the period of blasting works become long. This case study is related to urban apartment construction site. In order to overcome the weakness of general detonators which is required many blasting times to meet the day productivity, we have been applied deck-charge blasting method using electronic detonators and then we successfully increased the day productivity with much less blasting times. Hence, we had effectively achieved the declined neighbors'complaints and shortening construction period.

• Tunnel and Underground Space
• /
• v.24 no.5
• /
• pp.386-394
• /
• 2014

Drilling accuracy is known to be one of the most important factors determining blasting efficiency in mining by blast operation. Therefore analysing the causes of drilling error and preparing a countermeasure for minimizing drilling error are very important for blasting efficiency and safety. In this study, causes of drilling error are analyzed with dividing them into controllable factors and uncontrollable factors, and relationship between each cause is also comprehended through field measurement and AHP analysis. Finally, effective measures to help lower the drilling error are proposed with the results from weighting analysis for each factor.

• Explosives and Blasting
• /
• v.28 no.1
• /
• pp.40-54
• /
• 2010

The messer shield method applys mainly to a tunnel with small cross-section of a weathered soil or weathered rock district and is fulfilled mostly by man-power excavation. but in case that hard rock exposes on tunnel face, incredible is an application of the rock-splitting method using a hydraulic power or a blasting method. This study represents the case of a blasting method which can control to be practiced by the minimum charges of 125 g an initial vibration occurring at the cut instead of the rock-splitting method, even though water pipe and gas pipe are closely adjacent.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.5
• /
• pp.1-9
• /
• 2015

Recently Honam high-speed railroad line is constructed in southern part of Korea. This line is for next generation HST named HEMU-430X. But there is a limestone mine near this line and this mine will make a process to dig a passageway under the railway line. In this case, safety of railroad system and stability of mine are crucial problems on both sides. By measuring mine blasting vibration and calculating regression equation, effect of mine blasting to train running is investigated quantitatively. 0.5 kine (cm/sec) is applied as a management specification of vibration based on field measurement. In this study, changes of blasting patterns are suggested to control vibration of mine blasting. And the effect of train vibration to mine is also invesitigated by numerical analysis.

• Explosives and Blasting
• /
• v.26 no.2
• /
• pp.99-107
• /
• 2008

This study, to reduce a ground vibration damage of the structures in an area adjacent to housing structures located closely above the tunnel section, is the ground vibration reduction instance of a tunnel blasting selectively applied the ground vibration-controlled blasting method (delay time applied blasting method, large center hole cut method, Line Drilling method, etc) with an originally planned blasting method connected, but with it's workability and economic efficiency is satisfactory, so, the results says the ground vibration-controlled blasting method on a similar condition is very effective, even if the applicability is depend on the blasting method and ground condition of the work area.

• Explosives and Blasting
• /
• v.24 no.1
• /
• pp.57-62
• /
• 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
• /
• v.29 no.2
• /
• pp.81-88
• /
• 2011

Most of the blast pollution that causes complaints is noise and vibration. Hence, special attentions need to be paid to controlling the underwater noise in designing blasting for those areas. This study estimated underwater sound pressure using distance from blasting and charge per delay and underwater sound pressure level using the underwater sound pressure. To identify the validity of the estimated value, the study demonstrated the results at other areas and compared actual results with estimated results.

• Proceedings of the KSEE Conference
• /
• 2009.10a
• /
• pp.77-81
• /
• 2009

• Explosives and Blasting
• /
• v.31 no.2
• /
• pp.25-31
• /
• 2013

In this case of "Seongnam~Yeoju double-lanes railroad construction", there were resident houses and gas pipe which were concerned about damages from vibration and noise. Especially, gas pipe which is a diameter of ${\varphi}500mm$ was located under the ground along upside road. The limit of vibration was 1.0cm/sec to protect gas pipe. The electronic blasting systems have been used to control vibration & noise not only gas pipe but also resident houses. The results of tunnelling were successfully conducted with effective vibration control and quick excavation by electronic blasting without any damages to adjacent facilities.

• Geophysics and Geophysical Exploration
• /
• v.6 no.2
• /
• pp.71-76
• /
• 2003

Accurate estimation of the first arrival travel time is an essential task to obtain a high resolution velocity tomogram. Accuracy of the travel time estimation may be influenced by two factors; geological and mechanical. A serious mechanical factor is the source firing control problems. We found the control problems in the records generated by tome impulsive borehole sources. The problems are; irregular firing control and uncertainty in estimation of the absolute firing-times shown in records. Definitely, the time difference will introduce an error to the first arrival times, and accordingly; it will cause some distortion in the resulting velocity tomogram. A method to determine the firing time is suggested here. The method determines the optimum onset time by comparing the horizontal and the NMO velocity with various amount of delay time adjustment.