• Explosives and Blasting
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• v.15 no.3
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• pp.20-32
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• 1997

The pressure-time profile of the explosion gases can be controlled fot the use of cartridge explosives with two techniques Known as Decoupling and Spacing the charges. Decoupling consists in leaving and empty space between the explosive column and wall of the blast hole. Four different decoupling index, 1.4, 1.8, 2.34, 3.0 are selected in this field study. The level of ground vibrations with each decoupling index are measured and the empirical particle vibrations with each decoupling index are measured and the empirical particle velocity equation from these data was obtained. The condition of new cracks at blast hole are also examined. As the decoupling index in increased, the level of the blast vibration is decreased,. But the cracks in rock masses are efficiently formed to remove the broken rock. The vibration constant associated with a given site $K=1564.5(D.I)^{-1.3233}$ in terms of D.I(decopling index).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.1
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• pp.93-102
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• 2010

Greening sometimes fails because its method is not suitable for various site conditions, therefore the trend of selecting a revegetation method in Korea today is through test construction. However, due to enlargement, complication and diversification of domestic construction businesses, the importance of VE is gradually increasing as effective efforts over a whole life-cycle to obtain goals such as quality improvement and cost reduction, and not only quality and economic efficiency but also substantiality need to be considered in comparing revegetation methods. For this study, Sungnam~Janghowon (area1), where comparatively various slope revegetation methods are used, was selected the investigation site. The site was divided into three areas:blasting rock, ripping rock and earth sand. The revegetation methods used were six in the blasting rock area, five in the ripping rock area, and two in the earth sand region. 2007 monitoring data was analyzed, and Value (V) was calculated with LCC related ratio, and compared and contrasted with the evaluation of prior revegetation methods. Therefore it is believed that this analysis enables selection of the most appropriate method, unbiased towards one particular characteristic such as quality, vegetation growth and economy. When aiming for a durable effect, it shall be more efficient to select the most appropriate method focusing on LCC analysis, which deals with the economic aspect, as well as the design function aspect.

• Explosives and Blasting
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• v.34 no.4
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• pp.19-27
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• 2016

Much care should be taken when electric caps are used in blast site than when non-electric initiation systems are used. This is because electric caps can cause premature firing or misfires if stray currents of high magnitude flow into the blasting circuit. If the rock has higher electrical conductivity or lower electrical resistivity, such risks will be increased because the rock will provide more passages for the stray currents to flow into the blasting circuit. In this study, several rock samples obtained at a blast site were tested for electrical resistivity to decide whether electric caps could be used or not in the site. The measured electrical resistivity was $39{\sim}47{\Omega}{\cdot}m$ for the rock samples that had a higher content of metal sulfides. Contrary, the resistivity was $15000{\sim}21000{\Omega}{\cdot}m$ for ordinary rocks. Especially, in the case of the rock of electric resistivity of $39{\Omega}{\cdot}m$, only 2-V electric potential enables a stray current to flow through the rock of 1-m length, which can cause the premature firing of a detonator whose initiation current is 0.4 A. This result shows that electric initiation system should not be used in the site because rocks containing much amount of metal sulfides are widely distributed there.

• Explosives and Blasting
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• v.25 no.1
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• pp.45-52
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• 2007

When emulsion explosives(1kg/cartridge) are loaded into a long vertical borehole at open blasting site, they undergo an Impact corresponding to 117.6J of shock energy. After shocking. the crystallization of emulsion nay happen immediately. Furthermore, it nay cause a desensitization, arising from increase in the density of emulsion explosive by the breakage of sensitizer. In this paper, some experimental work was performed using PVC pipe equipment(50mm diameter and 12m lengths) to investigate the effects of loading impart of emulsion explosive. It is shown that detonation energy decreases up to 26% of the normal state value and this effect is less than 3% of the total performance of emulsion explosives in borehole blasting.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.7 s.112
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• pp.777-783
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• 2006

In this study, quantitative ground vibration values and damping coefficient produced by underwater blasting were measured and analyzed. Also, hydrospace noise in aquafarm and noise in atmosphere as well as ground vibrations were measured, and maximum values of these results were 86,8 dB(A), 147,8dB(A), 0.244 cm/s, respectively, With these results, vibration influence about snakehead (channa argus) and structures were examined. the damage of those was proved that is not. Equations of vibration ($V_{50%}=1.507SD^{-0.536},\;V_{95%}=2,171SD^{-0.536}$) and hydrospace noise ($SL=293.2SD^{-0.164}$) were presented from quantitative experiment results. respectively. The results of the study may be applied for the evaluation of the influence on aquafarm as a basic data before having main underwater blasting at construction sites.

• Explosives and Blasting
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• v.22 no.1
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• pp.57-65
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• 2004

Explosive blasting in tunnel excavation produces ground vibration and air blast as its side effects, which may cause complaints from nearby residents. This study was intended to investigate the propagation characteristics of ground vibration induced by tunnel blasting and to evaluate its effects on the residential structures near the site. We have conducted field measurements for 6 blasts and acquired vibration data from 70 measuring points, some of which on positioned inside the tunnel for comparative reason. Various documentation was reviewed to determine an allowable level of peak particle velocity for the residential structures in the area and the allowable limit was set to 0.5 cm/sec. Propagation equations for peak particle velocities were derived from regression analyses using the data acquired at both the surface and the underground tunnel. Finally we proposed appropriate predictive equations for the two areas and a safe blasting criterion.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.2
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• pp.129-139
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• 2006

When blasting by imposing the time difference between two adjacent charge holes, the mutual interference phenomenon occurs depending the feature of blast. This interference phenomenon of blast amplifies or compensates the blast-induced vibration depending on the overlapping mechanism. Thus, this experiment aims at finding out the optimum delay time by measuring the blast vibration data from the single hole blast during the blasting test and composing each blasting waveform, and at proving the its efficiency by applying the composition delay time in the entire cross section. The experiment showed that the blasting-induced vibration was reduced by endowing an optimum delay time of electronic detonator appropriate to the rock quality of construction site compared to the typical delay time (20, 25ms) of existing detonator (non-electric and electric detonator). From these results, the excavation efficiency using blasting could be enhanced..

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.3
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• pp.247-255
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• 2010

Bonding strength of shotcrete is a significant influential factor which plays the role of collapse prevention of tunnel crown and of debonding prevention of shotcrete induced by the blasting vibration. Thus, the evaluation of the shotcrete bonding state is one of the core components for shotcrete quality control. In this study, the peak particle velocities induced by blasting were measured on the shotcrete in a tunnel construction site and its effect on the bonding state of shotcrete is investigated. Drilling and blasting technique was used for the excavation of intersection tunnel connecting the main tunnel with the service tunnel. Blast-induced vibrations were monitored at some points of the main tunnel and the service tunnel. The shotcrete bonding state was evaluated by using impact-echo test coupled with the time-frequency domain analysis which is called short-time Fourier transformation. Analysis results of blast-induced vibrations and the time-frequency domain impact-echo signals showed that the blasting condition applied to the excavation of intersection tunnel hardly affects on the tunnel shotcrete bonding state. The general blasting practice in Korea was evaluated to have a minor negative impact on shotcrete quality.

• Smart Media Journal
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• v.12 no.11
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• pp.67-76
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• 2023

We propose a visualization method to respond to civil complaints through an analysis of the impact of blasting. In order to analyze the impact of blasting on tunnel excavation, we propose a simulation visualization method considering the mutual influence of the construction infrastructure by linking measurement data and 3D BIM model. First, the level of BIM modeling required for simulation was defined. In addition, vibration measurement data were collected for the GTX-A construction site, terrain and structure BIM were created, and a method for visualizing measurement data using blast vibration estimation was developed. Next, a spherical blasting influence source library was developed for visualization of the blasting influence source, and a specification table that could be linked with Revit Dynamo automation logic was constructed. Using this result, a method for easily visualizing the impact analysis of blasting vibration in 3D was proposed.

• Journal of Environmental Science International
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• v.13 no.1
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• pp.99-107
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• 2004

This research is to determine the level of environmental pollution at a blasting construction area which is the origin of noise, vibration, and suspended particle, and to compare the results with other domestic and international standard data. This experiment is also to find out the effects resulting from blasting construction and to propose a plan that can decrease environmental pollution. The blasting construction area is a factory site which is about one and half million square meter and sewage disposal plant is about ninety thousand square meter. Both were selected as the areas for the tests to be conducted in determination test. The test to determine the level of noise, vibration, and total suspended particle was conducted thirty times around the blasting construction area by comparing measurement results and numerical analysis. However, as the test was not conducted in the laboratory but in the actual blasting construction area, it was not possible to do the test with the same exact conditions each true. Therefore, the test was not ideal as conditions could change from test to test. For the most part, the level of noise was below the standard level of 70dB. Every vibration test was under the standard limitation. For example, a house, 200m away was tested for noise and vibration and the level was found to be under the 0.2 cm/sec which is the standard for specialty designed cultural sites., i.e very low level. Also a buried oil pipeline that was 30m away also marked under 2.0cm/sec which is the norm for an industrial area. However, if there were an oil pipeline under the house, the amount of charging gunpowder per hole should be decreased compared to the amount used in the test. The test result for suspended particles under the standard limitation which is 24hour average 300$\mu\textrm{g}$/㎥ at a distance from blasting wavelength, but at detonator, total suspended particle from the blast origin exceeded the standard limitation. If explosion occurs when it detonates in the hole, most of the energy would be absorbed in the crushing of rocks, but some remaining energy would make noises and vibration inevitable. So the important thing is how to minimize the environmental pollution from the blasting. There should be regulations in order that the standard limitation is not exceeded, and to decrease the environmental pollution from the blasting.