• Explosives and Blasting
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• v.41 no.3
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• pp.26-37
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• 2023

In order to determine the amount of explosives that can minimize the vibration generated during tunnel construction using the blasting method, it is necessary to derive the blasting vibration coefficients, K and n, by analyzing the vibration records of trial blasting in the field or under similar conditions. In this study, we aimed to develop a technique that can derive reasonable K and n when trial blasting cannot be performed. To this end, we collected full-scale trial blast data and studied how to predict the blast vibration coefficient (K, n) according to the type of explosive, center cut blasting method, rock origin and type, and rock grade using deep learning (DL). In addition, the correction value between full-scale and borehole trial blasting results was calculated to compensate for the limitations of the borehole trial blasting results and to carry out a design that aligns more closely with reality. In this study, when comparing the available explosive amount according to the borehole trial blasting result equation, the predictions from deep learning (DL) exceed 50%, and the result with the correction value is similar to other blast vibration estimation equations or about 20% more, enabling more economical design.

• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.41-53
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• 2022

In the excavation work like blasting/excavator work bordering on the urban railway, the dynamic safety of railway structures like tunnel, open-cut box structure and elevated bridge was investigated by numerical analysis in this study. The practically presented criteria on influential zones at the blasting work in the construction industry was numerically checked in cases of the precise vibration-controlled blasting (type II) and the small scale vibration-controlled blasting (type III) and it was shown that the criteria on blasting work methods needed to be supplemented through continuous field tests and numerical analyses. The influence of excavation vibration by mechanical excavators was especially investigated in case of earth auger and breaker. The numerical analysis of tunnel shows that the criteria on vibration velocities from the regression analysis of field test values was conservative. The amplification phenomenon of excavating vibration velocity was shown passing through the backfilling soil between the earth auger and the open-cut box structure. It was shown that the added-vibration on the superstructure of elevated bridge was occurred at the bottom of pile like earthquake when the excavator vibration was arriving at the pile toe. The systematic and continuous research on the vibration effect from excavating works was needed for the safety of urban railway structures and nearby facilities.

• Explosives and Blasting
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• v.33 no.2
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• pp.25-39
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• 2015

The common underwater rock removal methods involve underwater blasting and crane's chisel dropping impact method. From an environmental point of view, these methods cause ground vibrations and underwater noise. At the site for this study, a method of dropping heavyweight chisel is selected to remove the underwater bedrock near the ferry rack in the course of improving the cargo handling ability of the loading dock. A prediction formula for the vibration was obtained based on the measurement and evaluation of the vibrations caused by the chisel dropping impacts during the test droppings. The prediction formula was successfully applied to the main construction for securing the stability of the structure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.47-54
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• 2008

In this study, ground vibration values and damping coefficient produced by underwater blasting were measured and analyzed. Equations of vibration, $V=K(SD)^{-0.536}$, were presented from quantitative experiment results. The K Values are classified with 1.507, 2.005 and 2.939 respectively at 50%, 90% and 95% reliability. Also, hydrospace noise in aquafarm and noise in atmosphere as well as ground vibrations were measured, and maximum values of these results were 86.8dB(A), 147.8dB(A), 0.244cm/s, respectively. Equations of hydrospace noise, $SL=293.2SD^{-0.164}$, was presented from quantitative experiment results. Also, the flow-chart for influence estimation and underwater blast design was presented from these results. 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.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.103-118
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• 2021

For management and preservation measures of lava tube, it is studied how the blasting vibration by constructions near Geomunoreum lava tubes in Jeju affect lava tube. 11 boreholes were drilled in study area, and in-situ blasting tests were conducted by changing from 0.5 kg to 10 kg charge per delay in those boreholes. The vibration velocity, which meets the regulatory vibration criterion during daytime, was estimated as below 0.276 cm/sec by analyzing the relationship between vibration velocity and vibration level. In addition, SRE and CRE were calculated from the results of in-situ blasting tests, and k-values were shown as 130.04 in SRE, 199.71 in CRE, respectively. Also, n-values were shown as -1.717 in SRE, -1.711 in CRE, respectively. Charge per delay were assessed based on these equations, and charges per delay had ranges of 0.57~7.42 kg/delay in estimation equation of vibration velocity, 0.21~5.29 kg/delay in SRE, and 0.04~5.51 kg/delay in CRE, considering the 0.2 kine vibration criterion for cultural heritage and the 20~100 m distance from vibration source. Additionally, the relationships which meet the criteria of 0.2 kine, were calculated by combining CRE in this study with the result of previous study. Allowable charges per delay, which meet the criteria of 0.2 kine, were evaluated as 1.07 kg/delay in 50 m, 5.13 kg/delay in 100 m and 22.26 kg/delay in 200 m distances. These relationships for each vibration velocity are useful to deduce charge per delay for the ground near Geomunoreum lava tube.

• Explosives and Blasting
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• v.33 no.4
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• pp.14-24
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• 2015

We conducted test blasting in 3 sites to identify the effect on safety of the earth retaining wall by near blasting vibration. As a test result, we confirm that underground structures(earth anchor et al.) are relatively safer than surface structures as the underground vibration is 10~52% of surface vibration at a same distance. We derived surface and underground vibration prediction equations by regression analysis of measured 3 sites' surface and underground vibration PPV. Also we calculated minimum separation distance by blasting pattern about underground and surface curing concrete. Unless any discontinuity which are unsafe on the earth retaining wall appear, blasting work using under 2.4kg per delay is not meaningful to the earth retaining wall's safety as the result of measuring near blasting vibration, confirming change the earth retaining wall's instrument, and observation of structural deformation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.891-901
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• 2016

By comparing test blasting data experimented in three layered-structure polymorphic grounds to a geological profile, influence of blast vibration with respect to uncontrollable ground characteristics was analyzed. Inefficient blast have been performed without sufficient verifications or confirmations because insufficiencies with regard to experiments and data of blasting engineering on the layered structures to be irregularly repeated clinker layer consisted of volcanic clastic zones. It is difficult to quantify N values of clinkers within test blasting region because they have diverse ranges, or coverages. An absolute value of attenuation coefficient N in a field, estimated by blasting vibration predictive equation (SRSD), are lesser than criteria of a design instruction, meaning that vibrations caused by blast can spread far away, and the vibrational characteristics of blasting test No.1, indicating relatively small values, inferred by the geological profile, pressures of gas by the explosion may be lost into a widely distributed clinker layers by penetrating holes resulted from blast into vicinity of clinker layers located in bottom of soft rock layers at the moment of blast. As a result, amounts of spalling rocks are decreased by almost half. Also, ranges of primary frequencies in the fields are identified as similar to those of natural frequency of typical structures.

• Explosives and Blasting
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• v.35 no.1
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• pp.43-52
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• 2017

Mountain and hill areas occupy by more than 70% in South Korea and Rock drilling should be applied in order to reduce noisy & vibration from massive civil engineering business such as road expansion, high-way construction, subway construction and construction of site renovation such as a newly-built & re-development of apartment, newly-built of high-rising building in downtown area. As Blasting noise & vibration such as vibration, noise, fly rock etc caused by blasting operation from large small scale construction occurs, neighboring residents who demand the compensation file a civil complaint so that the business reach a deadlock. As the excavation method for these areas, There are blasting of micro-vibration, mechanical excavation method(Rock splitter, Breaker etc), similar blasting method(plasma, gel fragmentation etc) to date. In this study, we are trying to find the feature & performance which get improved economic feasibility & construct ability through improving sympathetic detonation of New KINECKER-I used in blasting of micro-vibration & formulation and would provide convenience for use by introducing standard blasting pattern & construction method. Also, checked and confirmed all the blasting with connecting cap has been cleary detonated.

• Explosives and Blasting
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• v.30 no.2
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• pp.1-8
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• 2012

The only law related to airblast and ground vibration control in Korea is the Noise and Vibration Control Act enforced by the Ministry of Environment. But this law mainly deals with the annoyance aspects of noises and vibrations in ordinary human life. Hence, the law defines the safety criteria of ground vibration as the vibration level (VL) of dB(V) unit. The ground vibrations produced from blasting, however, have the unique characteristics that can be shown in shock vibrations, and the duration is also very short compared to the vibrations from machinery, tools or facilities. Hence, vibration regulations for blasting operations usually define the safety criterion as the peak particle velocity (PPV) considering the effect of ground vibrations to structural damage. Notwithstanding, there are several attempts that predict VL from PPV or estimate VL based on the scaled distances (SD; in unit of $m/kg^{1/2}$ or $m/kg^{1/3}$) without considering their frequency spectra. It appears that these attempts are conducted mainly for the purpose of satisfying the law in blasting contracts. But, in principle there could no correlation between peaks of velocity and acceleration over entire frequency spectrum. Therefore, such correlations or estimations should be conducted only for the waves with the same or very similar frequency spectra.

• Explosives and Blasting
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• v.35 no.2
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• pp.1-8
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• 2017

In this study, the characteristics of a new rock cracking method using steam pressure are briefly presented. The rock cracking method was originally developed as a means to decrease the ground vibrations from underground rock excavations. The validation tests were also conducted by applying the method to an actual rock tunnel under construction. The ground vibrations were measured in the vicinity of the test site. The measured vibration results were compared with the values predicted by an attenuation equation, which had been proposed by a company in Japan. Also, a simple cost assessment for the method was conducted to demonstrate its cost effectiveness in underground tunnel excavations.