• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.391-398
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• 2004

The propagation mechanism of a detonation pressure with fully coupled charge is clarified and the blasting pressure propagated in rock mass is derived from the application of shock wave theory. Probabilistic distribution is obtained by using explosion tests on emulsion and rock property tests on granite in Seoul and then the probabilistic distribution of the blasting pressure is derived from their properties. The probabilistic distributions of explosive properties and rock properties show a normal distribution so that the blasting pressure propagated in rock can be also regarded as a normal distribution. Parametric analysis was performed to pinpoint the most influential parameter that affects the blasting pressure and it was found that the detonation velocity is the most sensitive parameter. Moreover, uncertainty analysis was performed to figure out the effect of each parameter uncertainty on the uncertainty of blasting pressure. Its result showed that uncertainty of natural rock properties constitutes the main portion of blasting pressure uncertainty rather than that of explosive properties.

• Explosives and Blasting
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• v.25 no.1
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• pp.15-29
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• 2007

In situ and laboratory tests were carried out for investigating the Excavation Disturbed Zone(EDZ) generated from blasting at the KAERI Underground Research Tunnel(KURT), which is for the researches related to High-level radioactive waste disposal program. It was found that the EDZ was generated more than In from the laboratory rock tests and in situ experiments. RQD of the rock mass within $0{\sim}2(m)$, where the blasting impact was significant, was 17% lower than in the deeper zones without a serious blasting impact. It was also estimated that the deformability of rock mass was reduced about 40% after the blasting.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.337-348
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• 2003

The propagation mechanism of a detonation pressure with fully coupled charge is clarified and the blasting pressure propagated in rock mass is derived from the application of shock wave theory. The blasting pressure was a function of detonation velocity, isentropic exponent, explosive density, Hugoniot parameters, and rock density. Probabilistic distribution is obtained by using explosion tests on emulsion and rock property tests on granite in Seoul and then the probabilistic distribution of the blasting pressure is derived from the above mentioned properties. The probabilistic distributions of explosive properties and rock properties show a normal distribution so that the blasting pressure propagated in rock can be also regarded as a normal distribution. Parametric analysis was performed to pinpoint the most influential parameter that affects the blasting pressure and it was found that the detonation velocity is the most sensitive parameter. Moreover, uncertainty analysis was performed to figure out the effect of each parameter uncertainty on the uncertainty of blasting pressure. Its result showed that uncertainty of natural rock properties constitutes the main portion of blasting pressure uncertainty rather than that of explosive properties. In other words, since rock property uncertainty is much larger than detonation velocity uncertainty the blasting pressure uncertainty is more influenced by the former than by the latter even though the detonation velocity is found to be the most influencing parameter on the blasting pressure.

• Tunnel and Underground Space
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• v.4 no.3
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• pp.228-236
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• 1994

• Explosives and Blasting
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• v.25 no.1
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• pp.67-77
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• 2007

The drill monitoring data are useful for the detection of abrupt and unexpected changes in ground renditions. This paper introduces a new approach to how drill performance parameters can be used for the prediction of quantitative rock mass properties ahead of tunnel face and the blasting design. The drill monitoring parameters available for the predictions include the instantaneous advance speed, thrust force, torque, tool pressure and penetration rate. The assessment of the drill monitoring parameters will be able to build a database provided that in-situ drill monitoring informations are accumulated and enable us to make a reasonable blast design based on quantitative assessment of rock mass.

• Explosives and Blasting
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• v.28 no.2
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• pp.133-147
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• 2010

A Suggestion of In-situ Rock Mass Evaluation and Correlation between Rock Mass Classfication MethodsThe purpose of this study is to find out rock mass classification method which is practically applicable to a field and to consider a correlation between the new method and the old method. Rock mass is an aggregate of separated blocks. To express the aggregate, the properties of both intact rock and rock mass should be considered. In this study, therefore, parameters for rock mass description are classified into rock strength and rock structure. Indices for parameters evaluation are obtained from old method and the strength and structure property of rock is described by using those indices. Value of 25 is allocated to each parameter obtained. $RMR_{basic}$ =0.86(X=Method)+14.47 is derived between $RMR_{basic}$ and this study and $RMR^*$ = 0.87(X-Method)+9.20 is derived between revised RMR and this study. Coefficient of determination is $R^2$=0.841 and $R^2$=0.846 each.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.930-937
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• 2004

In tunnel blasting, rock damage and overbreak at excavation limits are strongly related to stability of the tunnel and cost for rock support, and also affect to maintenance after tunnel construction. In this study, many field tests and measurements have been carried out in highway tunnels so that discordance between blast design and practical production blasting could be settled and actual methods of over break control could be proposed through the understanding of the problems in existing blasting patterns. Test blasting in tunnel was carried out many times in two tunnel sites. Also, long hole blasting longer than existing blasting pattern was executed for good grade of rock mass whose RMR value is more than 60. Using the results of test blasting, new standard blasting patterns for two lane tunnel were proposed. As a result of profile measurement after blasting, drilling is a major factor of overbreak. And then the methods for minimizing overbreak were adapted in new blasting patterns.

• Geomechanics and Engineering
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• v.16 no.4
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• pp.399-413
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• 2018

This paper addresses the issue of field measurement of excavation damage zone (EDZ) and its numerical simulation method considering both excavation unloading and blasting load effects. Firstly, a 2000 m-deep rock cavern in China is focused. A detailed analysis is conducted on the field measurement data regarding the mechanical response of rock masses subjected to excavation and blasting operation. The extent of EDZ is revealed 3.6 m-4.0 m, accounting for 28.6% of the cavern span, so it is significantly larger than rock caverns at conventional overburden depth. The rock mass mechanical response subjected to excavation and blasting is time-independent. Afterwards, based on findings of the field measurement data, a numerical evaluation method for EDZ determination considering both excavation unloading and blasting load effects is presented. The basic idea and general procedures are illustrated. It features a calibration operation of damage constant, which is defined in an elasto-plastic damage constitutive model, and a regression process of blasting load using field blasting vibration monitoring data. The numerical simulation results are basically consistent with the field measurement results. Further, some issues regarding the blasting loads, applicability of proposed numerical method, and some other factors are discussed. In conclusion, the field measurement data collected from the 2000 m-deep rock cavern and the corresponding findings will broaden the understanding of tunnel behavior subjected to excavation and blasting at great depth. Meanwhile, the presented numerical simulation method for EDZ determination considering both excavation unloading and blasting load effects can be used to evaluate rock caverns with similar characteristics.

• Tunnel and Underground Space
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• v.14 no.2
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• pp.108-120
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• 2004

Dynamic analysis has been increased recently to analyze the effect of the blasting vibration on the rock mass as well as the surrounding structures. The major input parameter far the general dynamic analysis, however, is merely the blasting pressure which can be obtained from the blasting pressure-time history curves. But in case of the complicate geological condition it is not simple to apply the blasting pressure on the numerical analysis because e ground vibration characteristics should be obtained considering the complexity of ground condition. Therefore the authors tried to use the blasting vibration waveform as an input data This vinylation frequency could be obtained from the test blasting in the Pasir mine, Indonesia. Through the dynamic numerical analysis on the slopes in Pasir, the current situation of this slope could be simulated precisely.

• Explosives and Blasting
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• v.24 no.1
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• pp.1-8
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• 2006

Recently, most of limestone quarries have been not mined by open-pit mining but by underground excavation to reduce environmental pollution. As a result, the size of underground galleries became bigger to maintain mass-production close to open-pit mining. However, the scale of pillars and galleries as well as the excavation methods may induce a few adverse problems for the stability of a mined gallery. In this study, the nomogram analysis and the prediction of rock damage zone induced by blasting were carried out. The testing conditions include concurrent blasting of two adjacent galleries, concurrent blasting of a transport drift and a inclined shaft, sequential blasting of two galleries, and separate blasting for each gallery. For each testing condition, blast vibration velocity was measured and analyzed. From the prediction formulas for blast vibration velocity derived in this study, the maximum depth of rock damage zone induced by blasting were also predicted.