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The paper tackles the issues of data acquisition during the measuring of vibrations caused by the detonation of explosive charges in various types of works (blasting in mines, demolition works, tunneling). Depending on the placement of an explosive charge (a charge detonated on the surface or a charge placed in a hole), it triggers side effects in...
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... mechanical-electrical diagram of a condenser microphone with internal polarization is shown in Figure 1. In such microphone, the diaphragm is a polyester film, teflon, or a similar material that is metallised, usually by gold spraying, to form a conductive surface, which is grounded by a metal washer. ...
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... building was a typical single-family building with a brick structure. For this analysis, measurements were taken at a distance of 6500 m (Figure 10) from the location where 450 kg of explosives were simultaneously detonated on the surface. The measurement results are shown in Figure 11. ...
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... this analysis, measurements were taken at a distance of 6500 m (Figure 10) from the location where 450 kg of explosives were simultaneously detonated on the surface. The measurement results are shown in Figure 11. On the other hand, Figure 12 shows the measurement results taken from the station located at a distance of 295 m (Figure 10) when 400 kg of explosives were simultaneously detonated. ...
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... measurement results are shown in Figure 11. On the other hand, Figure 12 shows the measurement results taken from the station located at a distance of 295 m (Figure 10) when 400 kg of explosives were simultaneously detonated. In both cases, the main propagation medium was the air. ...
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... measurement results are shown in Figure 11. On the other hand, Figure 12 shows the measurement results taken from the station located at a distance of 295 m (Figure 10) when 400 kg of explosives were simultaneously detonated. In both cases, the main propagation medium was the air. ...
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... both cases, the main propagation medium was the air. Figure 11 shows the results of the measurements taken at one of the stations during the first study phase. The main objective was to verify the effect of the detonation of explosive charges on buildings near the training area. ...
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... second phase of the study focused on the determination of safe areas for people who performed metal cladding works. The detonation of explosive charges caused ground vibrations (recorded in the range of 500-1250 ms- Figure 12), which was recorded at a 295-metre distance from the detonation site; however, their value is not comparable to that of the effect caused by the airblast wave (recorded at over 1250 ms). The characteristic frequency for the airblast wave and ground vibrations was 10 Hz and 10-30 Hz respectively. ...
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... m in a straight line. The results of the measurements at one of the stations are shown in Fig- ure 13 (sensor anchored in the ground in accordance with the manufacturer's instructions and microphone placed 1.5 m above the ground directly above the sensor, there was no air obstruction between the detonation site and the measuring station). In spite of the low mass of the explosive material, the detonation of shaped charges generates a very high airblast wave pressure compared to Figure 11. ...
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... results of the measurements at one of the stations are shown in Fig- ure 13 (sensor anchored in the ground in accordance with the manufacturer's instructions and microphone placed 1.5 m above the ground directly above the sensor, there was no air obstruction between the detonation site and the measuring station). In spite of the low mass of the explosive material, the detonation of shaped charges generates a very high airblast wave pressure compared to Figure 11. The airblast wave pressure could have interfered with the geophones again because the ground vibrations start at the same time as the airblast wave recording. ...
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... it could also be that the pressure from the airblast created vibrations in the ground. Ground-propagated vibrations occur in the record shown in Figure 13 for the time above 3500 ms, i.e., when the steel structure falls to the ground. The frequency response for the airblast wave differs from the previous examples except for the frequency of 15 Hz; there are also higher frequencies-45 and 75 Hz. ...
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... penultimate example covers the results of the measurements taken at one of the stations (Station 5) during the demolition of an 80-m reinforced concrete chimney using explosive materials (Figure 14). The distance from the measurement station to the detonation site was 98 m and to the location where the centre of gravity of the chimney fell was 80 m. ...
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... was no air obstruction between the detonation site and the measuring station. Two phases can be clearly distinguished in the record shown in Figure 15. The first one is associated with the detonation of explosive charges (0-2000 ms) where ground vibrations are small, whereas the other (from 11,500 ms) is associated with the fall of the chimney to the ground. ...
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... order to demonstrate that there was no airblast wave occurring above ground, the station was located on the surface above the blasting site and at a distance of approx. 160 m (Figure 16). The recorders were placed on the ground and in a building. ...
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... analysis of Figure 17 revealed that the vibrations recorded in the ground were much greater than the vibrations recorded in the building foundation. Frequencies of over 30 Hz dominate the vibration structure for both the ground and the foundation; frequencies for the microphone recorded were 5 and 18 Hz. ...
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... first phase involved measurements in field conditions, during which, small pyrotechnic charges were detonated followed by the detonation of larger explosive charges. These measurements were taken on the foundation of a building both inside (Station 3) and outside (Station 4)-on either side of the wall (Figure 18). The airblast wave pressure on both stations was also measured during the measurements of building vibrations. ...
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... building windows and doors were closed during the measurement. The measurement results are shown in Figure 19. The analysis of Figure 19 reveals that the sensor located outside the closed building (in black) recorded lower vibrations than the sensor located inside (in red). ...
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... measurement results are shown in Figure 19. The analysis of Figure 19 reveals that the sensor located outside the closed building (in black) recorded lower vibrations than the sensor located inside (in red). The findings are completely different for records made by the microphones. ...
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... of test results are shown in Figures 20-22 (the mass of the detonated explosive charge being 250 g with the charge placed on the surface; the distance to the measuring station being 90 m) and Figure 20 (the mass of detonated explosive charge being 1000 g with the charge placed in a hole; the distance to the measuring station being 90 m). Figure 21 shows the course of the A-weighting, C-weighting, and unweighted sound pressure level [34], while Figure 22 shows the spectrum at the maximum value of the sound pressure from Figure 21. ...
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... before, the measurements were taken both inside and outside the building. Examples of test results are shown in Figures 20-22 (the mass of the detonated explosive charge being 250 g with the charge placed on the surface; the distance to the measuring station being 90 m) and Figure 20 (the mass of detonated explosive charge being 1000 g with the charge placed in a hole; the distance to the measuring station being 90 m). Figure 21 shows the course of the A-weighting, C-weighting, and unweighted sound pressure level [34], while Figure 22 shows the spectrum at the maximum value of the sound pressure from Figure 21. ...
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... the case of vibration measurements performed in construction objects, the impact of the air overpressure on the sensor itself (mounted outside- Figures 11, 19, 20, and 23) and on the building itself (this is confirmed by the measurements shown in Figures 7 and 20, where the sensor was mounted inside a closed building). The measurements show that the air overpressure in the range of 120-150 Pa causes vibrations of the building. ...
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... in the last field example ( Figure 17) it was demonstrated that airblast wave microphones recording sound in rooms were generated as a result of material vibrations in the building and the transmission of sound energy. One of the hypotheses that is to be considered is that the microphone diaphragm started to vibrate due to the vibrations transmitted to the microphone stand through the ground. ...
Citations
... The dominant frequency of blast vibrations plays a crucial role in vibration persistence and its amplification or reduction characteristics in structures [22][23][24]. Several methods and models have been developed to predict and optimize blast-induced ground vibrations [25][26][27][28]. Guo and Li proposed a hybrid intelligent model using a least-squares support vector machine (LSSVM) optimized with a particle swarm algorithm (PSO) for vibration prediction [10,29]. ...
Monitoring induced vibrations caused by blasting works is becoming an increasingly common form of preventive activity conducted in open-pit mines. Measurement stations also record other events unrelated to blasting works. This article presents a comparison of the intensity of vibrations induced by blasting works in an open-pit mine and mining tremors in an underground mine. The recorded data and conducted analyses of vibration intensity and frequency structure also allowed for a comparison of the impact of vibrations on a building structure. Calculations and analyses, conducted in accordance with the procedures provided in the standard PN-B-02170:2016-12 and the rules for applying the Mining Seismic Intensity Scale MSIS-2017, demonstrated a stronger impact on the building from induced vibrations in an underground mine located 10 km away compared to vibrations induced by blasting operations conducted in an open-pit mine, which is approximately 600 m away from the building. The presented material constitutes a unique set of data that can be used to introduce any necessary corrections in the methodology of analyzing vibrations regarding their harmfulness to building structures. The velocity value of vibrations correlated with frequency alone, without taking into account the vibration duration, can lead to incorrect interpretation.
... Scholars generally believe that CO 2 gas explosion antireflection technology causes structural damage to the coal and rock mass under the joint action of stress and high-pressure gas. [28][29][30][31] Most scholars have studied two stages of gunpowder explosion, and only a few studies have distinguished the three stages completely. However, the CO 2 explosion process is continuous, the splitting effect of high-pressure CO 2 gas is continuous and cannot be ignored, and the radial vibration parameters of each stage in the life cycle of CO 2 gas explosion change significantly. ...
CO2 gas explosion is an important technology for coal seam permeability enhancement and fracturing, but the stage division of its life cycle is unclear, and research on the use of radial vibration characteristic parameters for stage division is lacking. To more accurately divide each stage of the life cycle and analyse the characteristics of each stage, a radial vibration mechanical model of CO2 gas explosion was constructed. A novel radial vibration laboratory test of a briquette under CO2 gas explosion was designed and conducted, and the characteristic parameters, such as the explosion radial vibration signal waveform, peak acceleration, velocity, and peak energy, were quantitatively analysed. The results show that there were three stages in the life cycle of a coal briquette under the action of a CO2 gas explosion. The first stage, from 0 to 1.507 ms, was the stress wave action stage, in which the peak acceleration and peak energy around the blasthole were 25.460 g and 9.480 × 10¹² (m/s)², respectively. The second stage, from 1.507 ms to 9.282 ms, was the CO2 gas explosion energy storage stage, in which the peak acceleration and peak energy around the blasthole were 1.478 g and 5.524 × 10⁷ (m/s)², respectively. The third stage, from 9.282 ms to 12.606 ms, was the CO2 splitting stage, in which the peak acceleration and peak energy around the blasthole were 6.527 g and 1.470 × 10⁹ (m/s)², respectively. The research results analysed after the CO2 gas explosion verify the promotion of gas splitting in the second and third stages, explain the evolution mechanism of radial vibration in each stage of CO2 explosion, and provide a theoretical basis for the optimal design of CO2 explosion technology.
... In a narrow sense, quality data refers to the data related to product quality, such as qualification rate, number of defective products, repair rate, and straight through rate. It has prominent volatility and can be collected through simple random sampling and full inspection [5]. Kinigstein and others designed the data acquisition scheme of electric energy meter based on the combination of power line carrier and wireless communication technology [6]. ...
In order to solve the problem of frequent switching and tripping of intelligent power meter and ineffective power failure, a quality data collection and quality monitoring based on acceleration sensor is proposed. Firstly, this paper briefly describes the objects and methods of quality data acquisition and quality monitoring of intelligent watt hour meter. At the same time, based on the analysis of the requirements of quality data acquisition and quality monitoring of intelligent watt hour meter and based on B/S architecture, the quality data acquisition and quality monitoring framework of intelligent watt hour meter is designed. Finally, an intelligent power meter quality monitoring interface with friendly interactive and real-time display acceleration sensor is built using SVG and JavaScript technology. The results show that the collection and monitoring data based on acceleration sensor, three batches of three-phase 0.2 intelligent electric energy meters, meet the operation requirements. Among them, the batch failure rate and classification failure rate in the operation of the third batch are low, and the sampling qualified rate is high, which is an excellent level. The intelligent power meter quality data collection and monitoring system of acceleration sensor can also meet the requirements of full life cycle monitoring of intelligent energy meter quality. It provides a new method for the data acquisition of intelligent electric energy meter and hopes to provide some references for the timely discovery and solution of the quality problems of intelligent electric energy meter in the future.
... This problem is very important, especially in the situation when impact measurements are carried out at a short distance from the place, e.g., during the detonation of explosive materials, and are to be used to assess their impact on buildings [28,29]. Therefore, the following sections of the article present examples of vibration measurements and recordings made by airblast and acoustic microphones during tests in the reverberation chamber of AGH UST in Krakow; then, the signals presented in an earlier work are filtered based on the authors' developed model and program [30]. ...
... Bearing in mind the examples of measurements presented in our earlier works [30], measurements were carried out in the reverberation chamber with the inclusion of an apparatus for measuring sound pressure levels in the 1 Hz-20 kHz band. The main purpose of this was to check the impact of the sound wave (recording with acoustic measurement microphones) on geophones and microphones used for airblast pressure measurement. ...
... Using two active QSC K10 loudspeakers and a KEITHLEY 3390 generator generated a series of test signals which were sinus modulated (sine sweep) in the 30-300 Hz range. At the very end, in the reverberation chamber, the same pyrotechnic material was set off, but with a relatively lower mass (3 g) than during field tests at the testing ground ( Figure 19 in [30]). Two examples of tests were selected to illustrate the experiments: ...
This article presents the results of studies on the impact of acoustic waves on geophones and microphones used to measure airblasts carried out in a reverberation chamber. During the tests, a number of test signals were generated, of which two are presented in this article: frequency-modulated sine (sine sweep) waves in the 30-300 Hz range, and the result of detonating 3 g of pyrotechnic material inside the chamber. Then, based on the short-time Fourier transform, the spectral subtraction method was used to remove unwanted disruption interfering with the recorded signal. Using MATLAB software, a program was written that was calibrated and adapted to the specifics of the measuring equipment based on the collected test results. As a result, it was possible to clean the signals of interference and obtain a vibration signal propagated by the substrate. The results are based on signals registered in the laboratory and made in field conditions during the detonation of explosive materials.
Explosive pollutants remaining in global soils are serious threats to human health and ecological safety. Soils contaminated by trinitrotoluene (TNT) and cyclotrimethylene trinitramine (RDX) are simulated in this study and remediated using vetiver grass and effective microorganism (EM) flora to determine the efficacy of combined remediation in reshaping the microenvironment and bacterial community of soils contaminated by explosives. The degradation rates of TNT and RDX after 60 days of combined remediation were 95.66% and 84.37%, respectively. Soil microbial activity and enzyme activities related to the nitrogen cycle were upregulated. The content of soil elements in the remediation group changed significantly. Vetiver remediation increased the diversity and significantly changed the structure of the microbial community. Notably, bacteria, such as Sphingomonadaceae and Actinobacteriota, which can degrade explosives, occupied the soil niche, and the Proteobacteria and Bacteroidota, which are involved in sugar metabolism, showed particularly increased abundance. The metabolism of soil carbohydrates, fatty acids, and amino acids was upregulated in the vetiver, EM flora, and combined vetiver+EM flora remediation groups, and the most significantly upregulated pathway was galactose metabolism. The combined vetiver and EM flora treatment of soil contaminated by explosives greatly improved the ecology of the soil microenvironment.
