• Explosives and Blasting
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• v.29 no.2
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• pp.59-66
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• 2011

A variety of risks caused by natural, technological and biological hazards threaten a business continuity of an organization. Business continuity is very important issue for all organizations and its proper management may control success and failure of an organization. Business continuity plan (BCP) may be defined as a management process which provides a business continuity. BCP includes risk management, operational continuity plan, response/ recovery, exercise/study and crisis communication, etc. Risk management is a systematic method to identify, analyze, evaluate and treat emergency risks and risk assessment is composed of identifying, analyzing and evaluating emergency risks. Risk assesment is the first step for making BCP. In this study, risk assessment has been conducted for sewer laying project. Through assessing risks, 18 risks that may threaten the construction operation are identified and it is founded to be that high levels of risks which require treatment are 'collapse of excavation surface', 'breakage of ground infra-facilities', 'noise & dust dispersion' and 'rise of material costs'.

• Explosives and Blasting
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• v.35 no.1
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• pp.18-26
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• 2017

In Analysis of Fragmentation of rock blasted, The photo analysis method has been mainly used and these image acquisitions are mainly obtained by digital image from the front of the crushed rock. However, Image analysis is basically advantage of the image of planar shooting not front shooting but There is no way to take a photograph of huge plane rock slope. Thus, Unavoidably It is resolved by distorting or extending the image filmed at the front as well as adjusting it similar to its angle of plane shooting. Lately, With advancing unmanned aerial vehicle, It can simply image the fragment conditions of blasted rock of a high-definition digital image and Through it, It can acquire the most planar image to angle which accumulate cataclastic rock and also can make image analysis. In this study, It has been confirmed that tolerance value of analysis result of image filmed flatly is markedly lower than the existing front filmed image.

• Explosives and Blasting
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• v.30 no.1
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• pp.37-51
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• 2012

In this case of "Seongnam~Yeoju double-lanes railroad construction", there were safety facilities which were concerned about damages from vibration and noise. In the project design stage, the rock-splitter method was designed to prevent them. The electronic blasting was considered to improve construction speed and economic value as an alternative tunnelling method, complying with the site's vibration criteria(cowhouse : 0.09cm/sec, residence : 0.2cm/sec). In the environment evaluation report of the eDev, tunnel electronic blasting systems, the blasting pollutions can be managed by the electronic blasting method. The results were successfully conducted with high speed construction without any damages to adjacent facilities.

• Explosives and Blasting
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• v.34 no.4
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• pp.1-9
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• 2016

For underwater steel structure, cut that underwater shaped charge device that combines a spring hose, which is an external device of pressure resistance and flexibility with flexible shaped charge, was invented. As a basic experiment for an optimum condition design, an penetration performance was compared by external device shape. To evaluate the result of an experiment, image analysis was carried out after obtaining the model by using the liquid rubber for the penetrated steel plate. To simulate the penetrating process of shaped charge, the AUTODYN program has been used. As a result of analysis, while the average penetration depth of circular and square shaped external devices were similar, the penetration quality was more uniform in the case of circle. In addition, water infiltration occurred in square case, displacement and strain rate according to the increase of the water pressure were measured high.

• Explosives and Blasting
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• v.23 no.1
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• pp.65-77
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• 2005

Reflecting the fact that there are increasing number of old high-story apartment structures in urban area, it is expected that the demand of blasting demolition will increase in the near future. It is of great important to make up for the insufficient empirical knowledge in blasting demolition through priori method such as computer simulation. Computer simulation of the blasting demolition involves complicated process. In the past domestic researches, two-dimensional bonded particle model was used to examine the overall demolition behavior of a five-story simple structure. It was observed that the two-dimensional simulation did not properly simulate the collapsing behavior of a structure mainly due to the reduced degree of freedom. In this study, three-dimensional simulation was tried. It consumed a great amount of calculation time, which limited the extent of the study. A few parameters, such as delay times, amount of charge at each hole, ball properties, were modified in order to check oui; their effect on the collapsing behavior. The differences were observed as expected but the collapsing behavior did not exactly coincide with the test blasting with a scaled model.

• Explosives and Blasting
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• v.21 no.3
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• pp.49-60
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• 2003

Nowadays it is tendency to make a remodelling or demolition of old structures with the rapid development of blasting technique. In this treatise it is arranged of improvement procedure of blasting demolition method in korea which was begun since August 1991. Recently, the blasting demolition method has much merits with 60-70% reduction effect of construction period than mechanical demolition method. and so that it has much economical points specially over than 5 storied high buildings. In order to maximalize economical effects of the blasting demolition method, environment safety and recycling, it must be needed. at first to develop the estimating programs against vibration, noise, flying stones, and dust. Also it is required to take a responsibility for using recycling materials after blasting demolition of old structures, and to be invested to advance the blasting demolition techniques.

• Explosives and Blasting
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• v.34 no.2
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• pp.1-9
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• 2016

In this study, the field tests were performed on V-cut, PLHBM 1 hole, PLHBM 2 hole in gneiss area in order to compare the effects of the vibration decay of a tunnel cut-hole according to the number of PLHBM holes with scaled distance. Based on the prediction equation of blasting vibration from the result of the tests, the decay rate of vibration were confirmed 21.8~61.1% using PLHBM 1 hole, 35.7~79.3% using PLHBM 2 hole for scaled distance within $10{\sim}100m/kg^{1/2}$ on the basis of V-cut PPV. As the scaled distance was increased, the effect of vibration decay was decreased. The effect of vibration decay of cut-hole for intial PLHBM 1~2 hole was significantly high.

• Explosives and Blasting
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• v.38 no.2
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• pp.1-12
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• 2020

Digital Image Correlation is a well-established method for displacements, strains and shape measurements of engineering objects. Stereo-camera 3D Digital Image Correlation (3D-DIC) systems have been developed to match the specific requirements for measurements posed by material and mechanical industries. Although DIC method provides the capabilities of scaling a field-of-view(FOV), dimensions of Geotechnical structure objects in many cases are too big to be measured with DIC based on a single camera pair. It can be the most important issue with applying 3D DIC to the measurement of Geotechnical structures. In this paper, We were present stereo vision conditions in a 3D DIC system that can be measured for large FOV(30×20m) and high precisions(z-displacement 0.5mm) of the ground objects with Stereo-camera DIC systems.

• Explosives and Blasting
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• v.22 no.3
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• pp.35-41
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• 2004

Many buildings have been bolt in Korea. Because blasting operations and more efficient to make excavate rock than other methods, it's more extensively used for new construction, enlargement of buildings, subway work, etc. However, blasting vibrations and sound often create pollution. A study, 'The place of gathering earth and sand to construct a building site in Yangsan', has been done in Gyo-dong, in Yangsan. There are two high-rise apartment and buildings, beside a construction site. The blasting vibrations and sound were monitored on the 1st, 4th floors in building(4th floor), and the results of the analysis are as follows: The blasting vibrations decreased being transmited from 1st floor to 4th floor.

• Explosives and Blasting
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• v.27 no.1
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• pp.21-31
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• 2009

An excavation damaged zone (EDZ) is created by fracturing, excavation or stress redistribution of tunnels. In this zone the mechanical and hydraulic properties of rock are changed, which makes additional cracks and serves as a dominant pathway of groundwater flow. In this study, an assessment on an EDZ size was practiced by the measurement of the deformation modulus at the KAERI underground research tunnel (KURT), and the information was applied to the modelling analysis using FLAC2D software. The EDZ at KURT fell into the range of 0.6~1.8m and the deformation moduli of the EDZ generally correspond to about 40% of intact rock mass. With a consideration of the EDZ in numerical analysis, tunnel displacements increased by about 65% and the maximum principal stress decreased to 58% from the case without EDZ. The plastic zone of the tunnel was enlarged to the crown and invert zones of the tunnel within the range of the length of rock bolts. About 2% of the total tunnel displacement with EDZ was suppressed by the KURT support system. It is anticipated that the investigation of an EDZ can be used as an important and fundamental research for validating the overall performance of a high level waste disposal system.