共查询到20条相似文献，搜索用时 31 毫秒
1.
Z. X. Zhang T. Naarttij rvi 《Fragblast: International Journal for Blasting and Fragmentation》2005,9(2):61-78
Due to the large-scale sub-level caving in Malmberget mine and the short distance between the mine and Malmberget town, the ground vibrations in the town have reached a high level since the year 2001 when large scale caving mining started. In order to control and reduce the high vibrations, LKAB launched a research project on active reduction of vibrations in Malmberget by using the wave interference or wave superposition method with electronic detonators. By means of this method, the vertical vibrations were reduced by 10% and the total vibration time for a ring blast was reduced by 80% according to five ring tests in the mine. For a further reduction of the vibrations, a second method, named changing initiation sequence in ring blasts, was developed on the basis of stress wave theory and the geographic conditions of the town and the mine. The second method has so far been applied in all of the drifts near the town, and the vibrations measured at the town show that the vertical vibrations caused by production blasts in the mine have been reduced by more than 31% on average. In addition, a third method, dividing a ring into two parts during blasting, was developed and used to reduce the ground vibrations from a number of very large rings in the mine. The results indicate that the vibrations have been reduced by more than 33%, and a more interesting and surprising result is that ore extraction has been increased by the third method. 相似文献
2.
Yagoub M. M. Alsereidi Aishah A. Mohamed Elfadil A. Periyasamy Punitha Alameri Reem Aldarmaki Salama Alhashmi Yaqein 《Natural Hazards》2020,100(1):111-132
Prediction and control of blast-induced ground vibration is a matter of concern in mining industry since long. Several approaches ranging from scaled distance regression, different numerical methods to wave superimposition theories have been tried by many researchers for better prediction and control of blast-induced ground vibration. Signature hole analysis is one of the popular simulation methods to predict the ground vibration generated due to production blast. It superimposes the recorded signature hole waveform using a computer program to predict the production blast-induced vibration. The technique inputs the designated time of detonation of each hole and superimposes the waves generated by each hole to predict the nearest value of peak particle velocity and frequency of blast-induced ground vibration. Although a very useful approach, it requires a computer program to simulate the linear superimposition of waveforms. The simulation is not possible for every blast as it takes time and also is difficult for field engineers to simulate every time, whereas it is always easy for blasting engineers to adapt and use an empirical equation/approach for prediction and control of blast-induced ground vibration than simulation. In this paper, an attempt has been made to develop an innovative and simplified analytical approach of signature hole analysis. The simplified sinusoidal wave equation is obtained from recorded signature hole ground vibration waveform properties and is superimposed mathematically according to the multi-hole blast design to predict the production blast-induced ground vibrations. The validation of the developed approach was done in three different sites, and up to 15% more accuracy in prediction of the blast, vibrations are achieved in comparison with signature hole analysis prediction.
相似文献3.
Drilling and blasting is a major technology in mining since it is necessary for the initial breakage of rock masses in mining. Only a fraction of the explosive energy is efficiently consumed in the actual breakage and displacement of the rock mass, and the rest of the energy is spent in undesirable effects, such as ground vibrations. The prediction of induced ground vibrations across a fractured rock mass is of great concern to rock engineers in assessing the stability of rock slopes in open pit mines. The waveform superposition method was used in the Gol-E-Gohar iron mine to simulate the production blast seismograms based upon the single-hole shot vibration measurements carried out at a distance of 39 m from the blast. The simulated production blast seismograms were then used as input to predict particle velocity time histories of blast vibrations in the mine wall using the universal distinct element code (UDEC). Simulated time histories of particle velocity showed a good agreement with the measured production blast time histories. Displacements and peak particle velocities were determined at various points of the engineered slope. The maximum displacement at the crest of the nearest bench in the X and Y directions was 26 mm, which is acceptable in regard to open pit slope stability. 相似文献
4.
D. P. Blair L. W. Armstrong 《Fragblast: International Journal for Blasting and Fragmentation》2001,5(1):108-129
There is a common belief within the blasting community that increasing the burden will increase the blast vibration. In order to test this belief in a direct sense, it would be desirable to fire single blastholes with various burdens and monitor the vibrations at many locations. A review of past literature indicates that such direct tests are rare and only scant data is available. Nevertheless, a detailed analysis of this and associated past work (on small-scale blocks and choke blasts) shows no convincing evidence of an influence of burden on blast vibration. On the other hand, by considering the role of reflected waves in a simple analytical model, reasoning is given to show that the vibration might well be insensitive to burden. In view of the scant data available, it was decided to conduct trials of a direct nature, in which 13 single blastholes were fired to a free face. The burdens chosen were 2.6 m, 5.2 m and 10.4 m, and the vibration was measured at typically 10 locations over the range 5 m to 50 m from each hole. The results clearly show that the vibration is independent of such burdens. Furthermore, a side-by-side comparison of a choke blast with a free-face blast showed that the vibration from the holes in the choke blast was not higher than the vibration from the holes in the free-face blast. The present work also shows that vibration, although insensitive to burden, is not insensitive to the condition (i.e., the degree of damage) of the surrounding rock mass. In this regard, blastholes in undamaged ground produce a significantly higher vibration than blastholes in damaged ground. This might well be the reason why pre splits and drop-cuts are observed to produce relatively high vibrations, i.e., it is not because such blasts typically involve large burdens, but rather that they are usually initiated in relatively undamaged ground. 相似文献
5.
Investigations were carried out at seven underground coal mines in India to characterise the responses of roof and pillars of underground workings to the vibrations induced by adjacent open-pit blasting. The roof rocks of the selected underground instrumented panels were having RMR between 36.7 to 57. Monitoring of strata behaviour was carried out before and after blasts. Arrangements were made to mount the transducers of seismographs in roof and pillars to monitor the vibration. Attempts were made to monitor the vibration simultaneously, for a blast, in the pillar and at the junction of the roof or away from the junction in the gallery. 102 sets of such vibration data were recorded in the underground mines. It was observed that the roof of underground roadways vibrated with higher peak particle velocity (PPV) compared to pillars. The amplification of vibration in the roof compared to pillars, away from the junction, was 1.02 to 2.58 times whereas at the junctions, it was 2.04 to 5.57 times. 相似文献
6.
Investigations were carried out at three underground coal mines in India to study the response of surface structures to underground
blasting and the likelihood of damage to the structures. The structures in the vicinity of the underground blasting area were
single and multistoried residential houses. The amplitudes of vibration due to underground blasting were monitored simultaneously
on the ground surface near the foundation of the structures and on various floors of the structures. The vibrations were also
monitored near the important surface installations. It was observed that the magnitude of vibration in structures decreased
with the increase in the height of the structures. The frequency of blast vibration from underground blasting was higher than
the natural frequency of the structures. Little energy was transmitted into the structures, which caused reduction in the
vibration level in the structures. The reduction in the vibration levels was up to 45% in the houses. It indicates that the
dominant frequency of blast vibration plays an important role in persistence of vibration and its amplification or reduction
characteristics in the structures. This paper deals with the effect of the vibrations on structures/houses standing above
the blasting faces in underground workings and their potential to likely damage to the structures at different Indian geo-mining
conditions. 相似文献
7.
G. R. Adhikari A. I. Theresraj H. S. Venkatesh R. Balachander R. N. Gupta 《Fragblast: International Journal for Blasting and Fragmentation》2004,8(2):85-94
A database of ground vibration due to blasting at 27 limestone quarries, located in various parts of India, has been created. The database contains peak particle velocity (PPV), frequency, other vibration related and blast design parameters. Regression analysis of the data is carried out to derive site constants of the USBM predictor equation for individual quarries. It is found that these site constants are correlated with each other. By combining all the data, a generalised predictor equation is developed to assess and control ground vibration. In addition, mean zone of attenuation has been delineated using the predictor equations of the individual quarries. The dominant frequency of ground vibration with respect to distance and the possibility of modifying it by changing delay intervals in production blasts are also examined. 相似文献
8.
G. R. Adhikari A. I. Theresraj R. N. Gupta 《Fragblast: International Journal for Blasting and Fragmentation》2005,9(2):79-92
Various methods of transducer mounting provide varying degrees of coupling between the transducer and the measurement surface. The influence of four of these methods on vibration measurements was studied. For this purpose, the first transducer was placed freely on a horizontal surface, the second one was 'sandbagged', the third one was 'spiked' and the fourth one was completely buried in soil. These transducers were mounted side by side and ground vibrations were monitored for 14 blasts at an opencast coal mine.
Ground vibrations in terms of peak particle velocity, peak vector sum and frequency with different mounting methods were analysed. Assuming the data of the buried transducer as the most acceptable one, relative values of other transducers were determined and plotted. For the given tolerance for instrumental and human errors, anomalous readings were found in some cases. The waveforms of the buried transducer were then compared with those of others. Clear distortion in the waveforms or a very low correlation coefficient between two waveforms was suspected poor coupling.
The results indicate that decoupling is most likely with the surface transducer. However, the sandbagged and spiked transducers are also prone to decoupling. Decoupling can result in higher or lower ground vibration. Therefore, burial should be the preferred method for mounting of transducers in soil. 相似文献
Ground vibrations in terms of peak particle velocity, peak vector sum and frequency with different mounting methods were analysed. Assuming the data of the buried transducer as the most acceptable one, relative values of other transducers were determined and plotted. For the given tolerance for instrumental and human errors, anomalous readings were found in some cases. The waveforms of the buried transducer were then compared with those of others. Clear distortion in the waveforms or a very low correlation coefficient between two waveforms was suspected poor coupling.
The results indicate that decoupling is most likely with the surface transducer. However, the sandbagged and spiked transducers are also prone to decoupling. Decoupling can result in higher or lower ground vibration. Therefore, burial should be the preferred method for mounting of transducers in soil. 相似文献
9.
Gang Chen Scott L. Huang 《Fragblast: International Journal for Blasting and Fragmentation》2001,5(1):91-107
In order to study the characteristics of ground vibrations caused by production blasts in an open pit gold mine and to evaluate the impact of the vibrations to buildings, a seismic survey was conducted at an open pit mine. Two monitoring lines with multiple seismic stations were surveyed. The first line had a length of 4,492 m and the second line runs approximately perpendicular to the first line with a length of 823 m. The seismographs recorded the particle acceleration, velocity, and displacement in longitudinal, transverse and vertical directions. The magnitudes of peak particle motions were calculated and compared with several established damage criteria used in mining and geotechnical/structure engineering. Empirical equations were established based on the field measurements. Analyses were also performed to exam the effects of geological structures on the attenuation of individual vibration components as well as the peak vector sum of the particle velocity. 相似文献
10.
G. F. Brent G. E. Smith G. N. Lye 《Fragblast: International Journal for Blasting and Fragmentation》2002,6(2):189-206
Wall control blasting practices arc necessary to reduce the impact of blasting on mine faces but can also have a significant negative impact on mine productivity and operating costs. The conventional practice in deep open pit mines is to use so-called trim blasts adjacent to pit walls. To provide burden relief these trim blasts have fewer rows than full production blasts and are fired to a cleared free-face: hence they are termed 'unchoked.' This practice leads to scheduling constraints on the pit operations and can cause ore dilution due to excessive muckpile movement. The use of such trim blasts stems from the perception that increased wall damage results from 'choked' blasts. These concerns are based on the unproven assumptions that blast vibration levels and explosive gas penetration increase with increased blast burden and face confinement. This paper describes work undertaken as part of a major investigation into wall control blasting at the KCGM Fimiston Mine, Kalgoorlie, Western Australia. It details a study to assess damage effects due to blast burden. Borehole air pressure measurements and borehole video camera inspections owere done behind a series of single blastholes drilled owith varying burden distances, as owell as behind a dedicated trim blast and a full production blast. It was found that the measured damage effects, including visible rock cracking, dilation, and the limited extent of gas penetration behind the blastholes, did not vary significantly with burden or blast type for the cases tested. This result was in complete agreement with detailed vibration measurements conducted by Blair and Armstrong [1] during the study, which found that vibration was independent of blast burden. As a result of these investigations, changes to the blasting practices at the mine were implemented. Dedicated trim blasts and free-face blasting have been replaced by modified production blasts and the practice of 'choking' blasts has been introduced. This has resulted in a significant improvement in productivity and cost savings without compromising pit wall integrity. 相似文献
11.
A. J. Prakash P. Palroy D. D. Misra 《Fragblast: International Journal for Blasting and Fragmentation》2004,8(1):51-60
This paper presents the influence of various discontinuities, natural or artificial, on magnitude and frequencies of blast induced ground vibrations. These discontinuities were geological faults, a pond, a shaft incline, a trench and a pre-split plane interposed in the path of vibration propagation. In the post-trench region, ground vibrations in terms of peak particle velocity were significantly reduced and dominant frequencies in higher bands were consequently observed. Depth of trench with respect to blastholes were varied and consequent vibration characteristics were analyzed. The techniques of creating a trench and pre-split plane were successfully implemented in controlling vibration and in increasing the explosives charge to meet the scheduled production target of an opencast mine. Comparisons of ground vibration characteristics affected by a trench and a pre-split plane of the same depth are described in the text. The findings lead to the conclusion that such experimental data are necessary for production blasting in open cast mines under constrained conditions. 相似文献
12.
G. R. Adhikari A. I. Theresraj R. N. Gupta 《Fragblast: International Journal for Blasting and Fragmentation》2004,8(1):41-49
The safety and stability of concrete and masonry dams is a great concern when blasting has to be conducted close to these dams in order to construct small hydro-electric projects. There is a danger of ground vibration amplification to those residential-type buildings that are built close to these dams.
Responses of three concrete and masonry dams were measured directly by conducting a number of blasts and by monitoring vibration in the ground as well as on the dams. The amplitudes and frequencies of the motions were analysed and vibration attenuation relations were derived. These relations were used to compare the vibration levels on the dams with those in the ground.
Because of close-in construction blasts that produced high frequency ground vibrations, there was no amplification of the ground vibrations by these dams. The measured amplitudes of ground vibration were comparable to those of the dams. 相似文献
Responses of three concrete and masonry dams were measured directly by conducting a number of blasts and by monitoring vibration in the ground as well as on the dams. The amplitudes and frequencies of the motions were analysed and vibration attenuation relations were derived. These relations were used to compare the vibration levels on the dams with those in the ground.
Because of close-in construction blasts that produced high frequency ground vibrations, there was no amplification of the ground vibrations by these dams. The measured amplitudes of ground vibration were comparable to those of the dams. 相似文献
13.
Manoj Khandelwal 《Geotechnical and Geological Engineering》2012,30(1):205-217
The purpose of this article is to evaluate and predict the blast induced ground vibration using different conventional vibration
predictors and artificial neural network (ANN) at a surface coal mine of India. Ground Vibration is a seismic wave that spread
out from the blast hole when detonated in a confined manner. 128 blast vibrations were recorded and monitored in and around
the surface coal mine at different strategic and vulnerable locations. Among these, 103 blast vibrations data sets were used
for the training of the ANN network as well as to determine site constants of various conventional vibration predictors, whereas
rest 25 blast vibration data sets were used for the validation and comparison by ANN and empirical formulas. Two types of
ANN model based on two parameters (maximum charge per delay and distance between blast face to monitoring point) and multiple
parameters (burden, spacing, charge length, maximum charge per delay and distance between blast face to monitoring point)
were used in the present study to predict the peak particle velocity. Finally, it is found that the ANN model based on multiple
input parameters have better prediction capability over two input parameters ANN model and conventional vibration predictors. 相似文献
14.
S. P. Singh 《Geotechnical and Geological Engineering》1996,14(1):41-50
Summary A variety of overbreak control techniques are used during excavation with the drill and blast system. Tracer blasting is used in Canadian underground mines to minimize blast damage and involves placing a low-strength detonating cord along the length of a blast hole prior to charging with ammonium nitrate-fuel oil (ANFO). The results of tracer blasting are not always consistent and its mechanism is only hazily comprehended. In the absence of a clearly defined mechanism, it is difficult to analyse the results of tracer blasting and to identify the factors responsible for the inconsistency of results.A series of bench blasts and pipe tests were carried out to investigate the mechanism of tracer blasting. The evidence indicated partial deflagration and desensitization of ANFO, thus reducing the total available explosive energy. The rock mass surrounding the traced blasthole experienced a low level of ground vibrations. As a result of the continuous side initiation of ANFO, energy partitioning was more in favour of gas energy. A mechanism of tracer blasting has been proposed and the factors responsible for the inconsistency of the results have been identified in this paper. 相似文献
15.
Monia Aloui Yannick Bleuzen Elhoucine Essefi Chedly Abbes 《Arabian Journal of Geosciences》2018,11(21):686
Blasting constitutes a beneficial industrial technology, used in quarries and mining production processes, which ensures the achievement of the expected results in a short period of time with relatively low cost. Nevertheless, a significant part of the used blasting energy is wasted in the form of ground vibration and air blast. Hence, blasting-induced ground vibrations are one of the fundamental problems in the mining industry which may cause severe damage to structures and plants nearby. Therefore, a vibration control study plays an important part in the minimization of the environmental effects of blasting in mines. This study represents an investigation reporting ground motion (measured in terms of peak particle velocity (mm/s)) and air blast overpressure measurements around the open-pit phosphate mine near Metlaoui area (southwestern Tunisia). It aimed to calculate the site’s constants: K (ground transmission coefficient) and n (site attenuation curve slope). The obtained site parameters allowed determining the propagation equation of the blast-induced seismic waves in the study area. The scope of this study was to predict the peak particle velocity when the amount of explosive charge and/or the distance were altered with minimum spoil to the environment. Also, a frequency overview of the study area revealed the dominance of low frequencies (>?40 Hz). Such values can cause damage to the nearby structures when a specific peak particle velocity value is reached by blasting. Moreover, this study demonstrated that all overpressure magnitudes were less than 134 dB, which is the safe limit of air blast level. 相似文献
16.
Nan Jiang Chuanbo Zhou Shiwei Lu Zhen Zhang 《Geotechnical and Geological Engineering》2018,36(3):1475-1489
Investigating the propagation and attenuation of blast vibration in rock slopes is the key point to assess the influence of underground mine blasting on overlaying open pit slopes stability and determining the potential risk. In this paper, Daye Iron Mine in China has been chosen as the case to study the effect of blast vibrations on overlaying open pit slopes due to underground mine blast. Firstly, the characteristics of blast loadings are analyzed by the dynamic finite element method. Then, a three dimensional (3D) numerical model of the open pit and the underground mine is made, which is verified by the field monitoring data to prove its reliability. The effect of blast vibration on overlaying open pit slope due to underground mine blasting are discussed based on the peak particle velocity (PPV) and the peak effective tensile stress (PETS) distribution characteristics which are calculated and analyzed by inputting the obtained blast vibration data into the numerical model. The results show that the effect of present mining blasting on the stability of pit slopes are limited because the simulated maximum PPV and PETS of monitoring point on slopes are all < 0.747 cm/s and 0.738 MPa. At last, according to numerical simulations of the underground mine blasting, the PPV predicting formulas for the slopes in Daye Open Pit Iron Mine is proposed based on the classic Sadaovsk formula. 相似文献
17.
Enhanced demand for coal and minerals in the country has forced mine operators for mass production through large opencast mines. Heavy blasting and a large amount of explosive use have led to increased environmental problems, which may have potential harm and causes a disturbance. Ground vibrations generated due to blasting operations in mines and quarries are a very important environmental aspect. It is clear that a small amount of total explosive energy is being utilized in blasting for breakage of rock mass, while the rest is being wasted. The amount of energy which is wasted causes various environmental issues such as ground vibrations, air overpressure, and fly rock. Ground vibrations caused by blasting cannot be eliminated entirely, yet they can be minimized as far as possible through a suitable blasting methodology. A considerable amount of work has been done to identify ground vibrations and assess the blast performance regarding the intensity of ground vibrations, i.e., peak particle velocity and frequency spectrum. However, not much research has done into reducing the seismic energy wasted during blasting leading to ground vibrations. In this paper, the blast-induced ground vibrations in three orthogonal directions, i.e., transverse, vertical, and longitudinal, were recorded at different distances using seismographs. An attempt has been made for the estimation of the percentage of explosive energy dissipated in the form of seismic energy with electronic and non-electric (NONEL) initiation system. signal processing techniques with the help of DADiSP software is used to study the same. 相似文献
18.
This study evaluates the impacts resulting from quarry-blasting operation on nearby buildings and structures as it generates ground vibration, air blast, and fly rocks. In this paper, first blasting operation and its possible environmental effects are defined. Then the methods of blast-vibration prediction and commonly accepted criteria to prevent damage were introduced. A field experimental work was conducted to minimize the vibration effects at Saribayir quarry as it is an identical case for the many quarries situated in and around Istanbul, Turkey. Although the local surrounding geology and rock mechanics have great influence on vibrations as uncontrollable parameter, the charge weight per delay, delay period, geometric parameters of the blasts were changed to solve the existing vibration problem in the studied quarry. To obtain a realistic result, 10 blasts were carried out and 30 seismic records were made in different places mainly very close the buildings and the other vulnerable structures around the quarry. The evaluation is performed whether the vibration level are within safe limits or not. The prediction equation based on scaled distance concept is also determined, however, it is a site-specific model and need to be updated when the quarry advances. The safe blast parameters which minimize the environmental effect were determined for the Saribayir quarry. 相似文献
19.
In bench blast design, not only the technical and economical aspects, such as block size, uniformity and cost, but also the elimination of environmental problems resulting from ground vibration and air blast should be taken into consideration. Prediction of ground vibration components is of great importance when responding to and avoiding environmentally-related complaints. This paper presents the results of ground vibration measurements carried out in a celestite open-pit mine during blast optimisation studies. The particle velocity components (longitudinal, transversal, vertical and peak) and the airblast measurement results were evaluated considering the scaled distance relationship. The statistical analysis of 47 data sets yielded an empirical relationship between peak particle velocity and scaled distance. This approach which is suggested for the present site gives the 50% line and the upper bound 95% prediction limit with reasonable correlation. 相似文献
20.
A number of factors influence the generation, propagation and intensity of ground vibrations. However, there are conflicting opinions with regard to the influence of the blast size on the intensity of ground vibrations. This paper discusses the experiments conducted in an opencast coal mine in India and a simulation study carried out to establish the influence of total charge in a blast on the intensity of ground vibrations. Studies clearly indicate that the total explosive charge in a blast has insignificant influence on the intensity of ground vibrations for distances between 100 m and 3000 m. 相似文献