共查询到20条相似文献，搜索用时 15 毫秒
1.
Optimum delay interval design in delay blasting 总被引：2，自引：0，他引：2
Tatsuya Hoshino Gento Mogi Kou Shaoquan 《Fragblast: International Journal for Blasting and Fragmentation》2000,4(2):139-148
The major concern of this research is the reduction of blast vibrations at certain points of foremost importance. A procedure for optimum delay interval design, considering detonation time errors of the electric detonators, was proposed. Using the relationship between the peak particle velocity (PPV) and the delay at certain points of interest which was calculated by means of a computer program by simulating the superposition of the vibration waves emitted from each borehole, one can usually select the optimal delay interval in order to minimize the PPV. But due to the variations in the actual delay caused by the detonation time errors, the expected PPV usually not only depends on the nominal delay but also on the sensitivity of the PPV. Therefore, the selection of the optimum time interval for a delay blast should be based on both the optimum as well as several sub-optimal time intervals as candidates. In addition, the detonation time errors should be taken into consideration. Also, a new design concept, called 'combined delay blasting', which uses electronic detonators, is proposed to further reduce the PPV at the points of interest. Estimated vibration time histories based on this concept and their PPVs indicated considerably favorable results. 相似文献
2.
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
3.
为评价地铁环境振动对某中心城区拟建住宅办公楼的影响,本文使用高灵敏度测试仪TROMINO对该建筑场地进行了24 h环境振动测试,得到了场地3个方向加速度和速度的实测数据。采用1/3倍频程分析法对实测数据进行处理,分析了不同时段场地振动变化规律,并将分析结果与国际标准ISO 2631关于此类建筑场地的振动限值进行对比。结果表明:有地铁运行时的环境振动峰值远大于无地铁运行时;无地铁运行时,地面振动加速度幅值介于10-5~10-1 gal之间,且无明显振动主频;有地铁运行时,振动幅值介于10-4~100 gal之间,并在晚高峰时段达到最大值0.8 gal;地铁运行引起的地面振动主频介于40~50 Hz之间。低频段内（2~8 Hz）场地振动加速度最大值约为0.030 gal,中高频段内（8~250 Hz）场地振动速度最大值为26.715 μm ·s-1,均满足标准要求。 相似文献
4.
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
5.
A Feasibility Study on Controlling Ground Vibrations Caused by Blasts in Malmberget Underground Mine
Z. X. Zhang P. -A. Lindqvist T. Naarttij rvi K. Wikstr m 《Fragblast: International Journal for Blasting and Fragmentation》2004,8(1):3-21
In order to control or reduce the ground vibrations caused by underground blasts in Malmberget mine, a number of blast tests were carried out during production blasts and a series of single shot waveforms were obtained. Then the single shot waveforms from the same ring or different rings were analysed and compared with each other. The results showed that the single shots are reproducible, meaning that the ground vibrations caused by underground blasts can be controlled by means of the interference of the vibration waveforms measured. Finally, a formal test using electronic detonators and employing an optimum delay time of 8 ms was done in production. The test for an 11-borehole ring shows that the maximum vertical ground vibrations are reduced to the maximum vertical vibrations of a single shot. Particularly, the total vibration history for the 11-borehole-ring blast is shortened to about 200 ms over a velocity of 2 mm/s. However, the total vibration history of a normal production blast of 11-borehole ring is always 1400 ms over a velocity of 2 mm/s, namely the total vibration time of a production blast can be reduced to one seventh of that of the common production blasts by using the vibration control method. This indicates that the vibration control method introduced in the paper is feasible for underground mining blasts. 相似文献
6.
W. Lu W. Hustrulid 《Fragblast: International Journal for Blasting and Fragmentation》2003,7(4):231-255
Airdecking is used in mining for two quite different applications. One is to enhance the fragmentation by amplifying the induced fracturing and the second is for pre-split blasting in which the borehole fracturing is reduced. This paper deals with the first of these effects. A forth coming paper will describe pre-splitting by airdecking. The use of air decks to enhance rock fragmentation and so to reduce explosive costs has been the practice for quite long time. Although a number of studies has been conducted to verify the advantages of blasting with air decks and to investigate the mechanisms involved, the proposed mechanisms still cannot explain clearly the phenomena observed in practice and the design approach adopted for this kind of blasting is still primary based on rules-of-thumb. In this paper, the theory of shock tubes is adopted to (a) investigate the processes of the expanding detonation products, (b) study the interactions between the explosion products and the stemming or bottom of blasthole, and (c) to decide the distribution of the changing pressure of explosion products along blasthole. Numerical simulation and theoretical analyses are then performed to study the physical process of blasting with air decks. Finally, a reasonable value for the airdecking ratio is decided theoretically. It is shown that the pressure-unloading process caused by the propagation of the rarefaction wave and the reflected rarefaction waves in the detonation products plays an important role in the enhanced fragmentation of rock when blasting with air decks. The unloading process can induce tensile stresses of rather high magnitude in the rock mass surrounding blasthole. This favors fracturing of the rock. The reflected shock wave with a magnitude of gas pressure higher than that of the average detonation pressure in a fully charged blasthole acts as the main energy source to break the rock in the air deck and stemming portions. The second and succeeding strain waves induced by the unloading or reloading of the pressurewithin the blasthole also contribute to form the initial fracture network in the rock around the blasthole. It is also revealed that there exists a reasonable range of values for the airdecking ratio. For ANFO, this value varies from 0.13-0.40. 相似文献
7.
David M. Jenkins 《Physics and Chemistry of Minerals》1989,16(4):408-414
A detailed evaluation of the assignments given to the infrared (IR) vibrations in the lattice stretching region is presented here based on observations of the effects of various chemical substitutions in synthetic analogues of phlogopite, KMg3(AlSi3)O10(OH)2. As in previous studies, this study has confirmed that the 995, 960, and 460 cm?1 vibrations are influenced by Si, the 822 and 760 cm?1 vibrations by Al, the 915 and 725 cm?1 vibrations by Al and Si, and the 592 cm?1 vibration by OH. Contrary to previous studies, it is shown here that the 690, 495, and 375 cm?1 vibrations are strongly linked with Mg and not just Si. The 655 cm?1 band in phlogopite is attributed to an in-plane Al-O vibration rather than an Al-O-Si vibration. As a check on the band assignments made here, IR spectra were obtained for synthetic clintonite, CaMg2Al(Al3Si)O10(OH)2, as well as its chemical analogues and compared with the IR spectrum of phlogopite. The band intensities for the Si-O, Al-O, and Si-O-Mg vibrations changed in accord with the composition of clintonite. The most intense band in clintonite at 660 cm?1 appears to be associated only with Al and is assigned here to a tetrahedral Al-O-Al vibration which must be present, if not dominant, in this mineral. The near coincidence of an in-plane Al-O vibration at 655 cm?1 (phlogopite) and an in-plane Al-O-Al vibration at 660 cm?1 (clintonite) makes the identification of tetrahedral Al-Si order-disorder in trioctahedral layered silicates by IR spectroscopy very difficult. The ratio of the 822/995 cm?1 bands may, however, prove to be very useful for discerning the amount of tetrahedrally coordinated Al in these types of minerals. 相似文献
8.
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
9.
爆破震动灾害主动控制方法研究 总被引：3，自引：0，他引：3
在微差爆破工程中,用干扰降震法实现爆破震动灾害主动控制的关键在于确定合理的微差延期时间。由于所使用的普通雷管存在延期误差,设计或选择的延期微差时间往往与实际的有较大出入,影响了微差爆破的效果和顺利实施。确定微差爆破中的实际微差延迟时间对优化微差爆破效果、降低爆破地震效应具有很大的现实意义。用基于小波分析的时能密度法以及信号时-频域转换技术,从实测微差爆破震动信号中分离出各分段震波,通过比较各分段震波在不同延期时间下的叠加效果,得到了微差爆破的较优微差延期时间,实现了爆破震动灾害主动控制。该方法对研究爆破震动效应及其灾害的控制,具有较高的理论和应用价值,为系统开展爆破震动危害控制和预测研究奠定了理论和技术基础。 相似文献
10.
深埋洞室爆破开挖过程中围岩初始地应力的瞬态卸荷会诱发振动。针对圆形隧洞开挖,分析了地应力瞬态卸荷过程中围岩应变能、动能、径向应力做功3者之间的平衡机制,并采用量纲分析,建立了基于开挖岩体应变能的瞬态卸荷诱发振动衰减公式。结合锦屏二级引水隧洞和瀑布沟地下主厂房爆破开挖实例,开展了瞬态卸荷诱发振动的识别分离,并分析了诱发振动的衰减规律。研究表明：地应力瞬态卸荷诱发振动的峰值与被开挖岩体应变能密度的二次方根成正比,且开挖卸荷体积越大,诱发振动越强烈;与Lu-Hustrulid衰减公式相比,新衰减公式应用范围更广,使用精度更高。 相似文献
11.
A. Alipour M. Mokhtarian J. Abdollahei Sharif 《Journal of the Geological Society of India》2012,79(6):652-658
Ground vibration due to blasting causes damages in the existence of the surface structures nearby the mine. The study of vibration control plays an important role in minimizing environmental effects of blasting in mines. Ground vibration regulations primarily rely on the peak particle velocity (PPV, mm/s). Prediction of maximum charge weight per delay (Q, kg) by distance from blasting face up to vibration monitoring point as well as allowable PPV was proposed in order to perform under control blasting and therefore avoiding damages on structures nearby the mine. Various empirical predictor equations have proposed to determine the PPV and maximum charge per delay. Maximum charge per delay is calculated by using PPV predictors indirectly or Q predictor directly. This paper presents the results of ground vibration measurement induced by bench blasting in Sungun copper mine in Iran. The scope of this study is to evaluate the capability of two different methods in order to predict maximum charge per delay. A comparison between two ways of investigations including empirical equations and artificial neural network (ANN) are presented. It has been shown that the applicability of ANN method is more promising than any under study empirical equations. 相似文献
12.
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
13.
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
14.
Okan Su 《Rock Mechanics and Rock Engineering》2016,49(2):541-553
Electro-hydraulic and jumbo drills are commonly used for underground coal mines and tunnel drives for the purpose of blasthole drilling and rock bolt installations. Not only machine parameters but also environmental conditions have significant effects on drilling. This study characterizes the performance of button bits during blasthole drilling in coal measure rocks by using multiple regression analyses. The penetration rate of jumbo and electro-hydraulic drills was measured in the field by employing bits in different diameters and the specific energy of the drilling was calculated at various locations, including highway tunnels and underground roadways of coal mines. Large block samples were collected from each location at which in situ drilling measurements were performed. Then, the effects of rock properties and machine parameters on the drilling performance were examined. Multiple regression models were developed for the prediction of the specific energy of the drilling and the penetration rate. The results revealed that hole area, impact (blow) energy, blows per minute of the piston within the drill, and some rock properties, such as the uniaxial compressive strength (UCS) and the drilling rate index (DRI), influence the drill performance. 相似文献
15.
Xuecheng Bian Chong Cheng Jianqun Jiang Renpeng Chen Yunmin Chen 《Acta Geotechnica》2016,11(2):281-294
High-speed train induced vibrations of track structure and underlying soils differ from that induced by low-speed train. Determining the critical speed of train operation remains difficult due to the complex properties of the track, embankment and ground. A dynamic analysis model comprising track, embankment and layered ground was presented based on the two-and-half-dimensional (2.5D) finite elements combining with thin-layer elements to predict vibrations generated by train moving loads. The track structure is modeled as an Euler–Bernoulli beam resting on embankment. The train is treated as a series of moving axle loads; the embankment and ground are modeled by the 2.5D finite elements. The dynamic responses of the track structure and the ground under constant and vibrating moving loads at various speeds are presented. The results show that the critical speed of a train moving on an embankment is higher than the Rayleigh wave velocity of the underlying soil, attributed to the presence of the track structure and the embankment. It is found that the dynamic response of ground induced by moving constant loads is mostly dominated by train speed. While for the moving load with vibration frequency, the ground response is mostly affected by the vibration frequency instead of train speed. Mach effect appears when the train speed exceeds the critical speed of the track–embankment–ground system. 相似文献
16.
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17.
18.
Effect of Blast-Induced Vibration from New Railway Tunnel on Existing Adjacent Railway Tunnel in Xinjiang, China 总被引：1，自引：1，他引：0
The vibrations of existing service tunnels induced by blast-excavation of adjacent tunnels have attracted much attention from both academics and engineers during recent decades in China. The blasting vibration velocity (BVV) is the most widely used controlling index for in situ monitoring and safety assessment of existing lining structures. Although numerous in situ tests and simulations had been carried out to investigate blast-induced vibrations of existing tunnels due to excavation of new tunnels (mostly by bench excavation method), research on the overall dynamical response of existing service tunnels in terms of not only BVV but also stress/strain seemed limited for new tunnels excavated by the full-section blasting method. In this paper, the impacts of blast-induced vibrations from a new tunnel on an existing railway tunnel in Xinjiang, China were comprehensively investigated by using laboratory tests, in situ monitoring and numerical simulations. The measured data from laboratory tests and in situ monitoring were used to determine the parameters needed for numerical simulations, and were compared with the calculated results. Based on the results from in situ monitoring and numerical simulations, which were consistent with each other, the original blasting design and corresponding parameters were adjusted to reduce the maximum BVV, which proved to be effective and safe. The effect of both the static stress before blasting vibrations and the dynamic stress induced by blasting on the total stresses in the existing tunnel lining is also discussed. The methods and related results presented could be applied in projects with similar ground and distance between old and new tunnels if the new tunnel is to be excavated by the full-section blasting method. 相似文献
19.
Compaction of granular soils by uniform vibration equivalent to vibrodriving of piles 总被引：2，自引：0，他引：2
Summary A programme of laboratory tests was undertaken to identify the volume reduction of a range of granular soils in response to uniform vibration. The purpose of the tests was to quantify the potential compaction settlement of granular soils due to vibrations typical of those experienced when sheet or bearing piles are installed or extracted by vibrodriver. The vibrations in soils within 2–20 m of a vibrodriven pile are well defined as sinusoidal, at the frequency of the vibrodriver, and typically in the range of 1.0g down to 0.02g (whereg=gravitational acceleration). Thein-situ conditions were replicated in the laboratory by vibration of a Rowe cell containing a soil sample. This allowed control of stresses before and during vibration. Tests were conducted on nine granular soils, ranging from uniform Leighton Buzzard sands to a sandy fine-to-medium gravel. Soil samples were prepared at minimum relative density, generally in the saturated state, but also dry and partly saturated. Each sample was consolidated at a selected effective stress of between 10 and 100 kPa. It was then vibrated vertically at increments of controlled acceleration, under conditions of free drainage and maintained confining stress. Reduction in sample thickness was measured continuously. Results showed that even in a small, drained, sample the full volume reduction was reached only after many minutes, although the early response was more rapid. The trends of results showed that: increased surcharge pressure reduced the subsequent vibratory compaction; well-graded soils showed greater compaction than more uniform sands; compaction increased markedly when acceleration exceeded 1 g; saturated soils showed larger compaction than dry and partially saturated soils; compaction was influenced little by frequency, although rate of compaction reduced with frequency increase. 相似文献
20.
单自由面爆破条件下作用在岩体上的最有效破坏力小,而阻碍岩体破坏的作用力很大,使炮孔堵塞长度对爆破振动有较大影响。因此,研究单自由面爆破振动特征的炮孔堵塞长度效应有重要意义。进行了小规模的不同堵塞长度的单自由面爆破试验,并模拟了其爆破过程。研究表明,近距范围内爆破振动速度迅速衰减,中远距离爆破振动速度衰减趋缓;随着堵塞长度的增加,场地系数K不断增加,衰减指数? 总体呈上升趋势;数值模拟振动速度值与实测值误差在15%以内;爆破后不同堵塞长度模型的堵塞物底部空腔半径基本相等,约为装药半径的3倍;试验最优堵塞长度为15～20 cm,相同条件下无堵塞爆破对孔口有效应力场影响较大、对孔底有效应力场影响较小 相似文献