• Tunnel and Underground Space
• /
• v.17 no.6
• /
• pp.484-492
• /
• 2007

The blasting vibration prediction in the country is mainly carried out by using the scaled distance method. But, this method needs a real-scale test blasting. The blasting vibration prediction has been performed using the data measured at borehole blasting for the purpose of a geological investigation before beginning a construction of a tunnel. In this prediction method, it is difficult to reflect the propagation characteristics of ground vibration generated from a real-scale blasting. propagation. This paper presents a new method for estimating blasting vibration by using superposed data of single hole blasting waveform with a delay time.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.04a
• /
• pp.150-151
• /
• 2022

Blasting is a method that uses explosives to crush the ground. This method is a highly efficient ground cleaning method that can secure high efficiency in a short time. However, explosions can damage local properties and produce high noise and vibration. Therefore, it is important to be careful because there are disadvantages such as the occurrence of many complaints from the surrounding area. In this paper measured and analyzed the noise and vibration generated during blasting at the blasting site in Korea. The noise and vibration generated during blasting were measured by ES03303.2b and ES03402.2a at a distance of 6 m, 12 m from the blasting point. As a result of the measurement, there was little difference between small and medium scale except for precision vibration blasting at a distance of 6m, but noise difference according to blasting scale was evident at a distance of 12m. As a result of the measurement, the maximum noise level was reduced to 5.5 dB(A) and the vibration level was reduced to 7.7 dB(V). In the future, the reliability of the test results can be further improved through additional tests, and it is judged that noise and vibration prediction models based on blasting methods, amount of charge, measuring distance, etc. can be developed.

• Explosives and Blasting
• /
• v.23 no.3
• /
• pp.57-74
• /
• 2005

In the past, explosives like dynamite was used to blast rock. However, today it is difficult to use explosives in urban blastinglike excavation for subway, building, and housing land. According to Korea Department of Construction and Transportation's proposal for blasting design manual and test blasting, from TYPE I blasting to TYPE IV blasting are recommended when we determine 0.3cm/sec(centisec) as a maximum allowable ground vibration with a distance between $25m\~120m$ from structures. This article was written to introduce one of TYPE I (reck blasting within 25m from structures) blasting method, Nano-Plasma blasting method. When Nano-Plasma blasting method is applied in urban blasting job, ground vibration (15m away from blasting point) is expected 0.1cm/sec, which is only half of a ground vibration when low ground vibration blasting method is applied. By this unique characteristic, Nano-Plasma blasting method is epochal urban blasting technique.

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

• Explosives and Blasting
• /
• v.22 no.3
• /
• pp.43-55
• /
• 2004

Use term of tower style construction exceeds recently. Accordingly, according to construction safety diagnosis result, achieve removal or Improvement construction. But when work removal, must shorten shut down time. Therefore, removal method of construction to use blasting demolition of construction is very profitable. Influence construction and equipment by blasting vibration and occurrence vibration caused by felling impact. Is using disadvantageous machine removal method of construction by and economic performance by effect of such vibartion. Therefore, this research studied techniques to forecast vibartion level happened at blasting demolition and vibration reduction techniques by use a scaled model test.

• Journal of the Korean institute of surface engineering
• /
• v.39 no.4
• /
• pp.190-197
• /
• 2006

The effects of blasting and acidic treatment on the corrosion characteristics of dental implant fabricated with Cp-Ti and Ti-6Al-4V alloy have been researched by using electrochemical methods. The fabricated implants were cleaned and sandblasted by $Al_2O_3$ powder and then acidic treatment was carried out in nitric acid solution. The surface morphology were observed using scanning electron microscope. The corrosion behaviors were investigated using potentiosat and EIS in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The potentio-dynamic test in 0.9% NaCl indicated that the corrosion potential of blasting and acidic treated implant was lower than that of non treated implant, but current density was higher than that of non treated implant. From the cyclic potentiodynamic test results of Ti implant, the passivation current density of blasting and acidic treated implant slightly higher than that of non treated implant. From A.C. impedance test results in 0.9% NaCl solution, polarization resistance($R_p$) value of blasting and acidic treated implant was lower than that of non treated implant. In case of blasting and acidic treated implant surface, the pits were observed in valley and crest of implant surface.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.535-542
• /
• 2010

Various difficulties have been increased in the construction of public structure; like the road in the overcrowding urban area, because of civil complaint, cost and period of construction. In oder to overcome these social problems, the tunnel has been planned the road design. Despite the resolution, there are many technical problems when constructed near facilities. The design of new tunnel below the existing service reservoir is applied to the ambient vibration blasting using Plasma. The result of test blasting was exceeded the standard ("2kine"). So it was considered a countermeasure for the vibration reduction applied to change the controlled blasting method, reduce the charge, add the pre middle horizontal hole in the cut blasting site, and so on. The result was satisfied the standard. Accordingly, if the quality of blasting process can be managed well, the application of this alternative method is highly effective one. Also, based on cost analysis between two methods, the alternative method is very competitive.

• Tunnel and Underground Space
• /
• v.5 no.2
• /
• pp.134-143
• /
• 1995

Effects of blasting vibrations on curing concrete have not been well studied. As a result, unreasonable and strong blasting vibration constraints have been placed on blasting when it occurs in the vicinity of curing concrete. To study the effects of blasting on curing concrete blocks of 33.3X27.7X16.2 cm were molded and placed on the quarry. Several sets of concrete blocks were subjected separately to peak vibrations of 0.25, 0.5. 1.0, 5.0, and 10cm/sec. The impulses of blasting vibrations were applied with thirty-minute intervals. Along with unvibrated concrete blocks, the vibrated concrete samples cored with 60.3 mm in diameter were measured for elastic moduli, sonic velocity and uniaxial compressive strength. Test results can be summarized as follows; 1. The blasting vibrations between 6 and 8 hours after pour generally lowered on the uniaxial compressive strength of the concrete. 2. A low blasting vibration of 0.25 cm/sec did not affect the uniaxial compressive strength. As the magnitude of the blasting vibration increases, compressive strength of concrete is decreased. 3. Physical properties of the P-wave velocity, Young's modulus, and Poisson's ratio showed a weakly decreasing trend in the concrete blocks vibrated between 6 and 8 hours after pour.

• Geomechanics and Engineering
• /
• v.9 no.3
• /
• pp.329-344
• /
• 2015

Cratering tests in rock are generally carried out to identify its fragmentation characteristics. The test results can be used to estimate the minimum amount of explosives required for the target volume of rock fragmentation. However, it is not easy to perform this type of test due to its high cost and difficulty in securing the test site with the same ground conditions as the site where blasting is to be performed. Consequently, this study investigates the characteristics of rock fragmentation by using the hydrocode in the platform of AUTODYN. The effectiveness of the numerical models adopted are validated against several cratering test results available in the literature, and the effects of rock mass classification and ground formation on crater size are examined. The numerical analysis shows that the dimension of a crater is increased with a decrease in rock quality, and the formation of a crater is highly dependent on a rock of lowest quality in the case of mixed ground. It is expected that the results of the present study can also be applied to the estimation of the level and extent of the damage induced by blasting in concrete structures.

• Tunnel and Underground Space
• /
• v.10 no.2
• /
• pp.211-217
• /
• 2000

In this, study, some laboratory tests and in-situ test were performed for Taegu area. Test blasting was conducted to determine blasting vibration coefficients. The uniaxial strength of rocks vary widely from weathered rock to extremely hard rock. Boasting vibration coefficient, K and n were 114.8, 1.48 for Sungseu site, where rocks show weathered to medium strength.