Bench blasting design based on site-specific attenuation formula in a quarry

This research was performed on the quarry that will be opened to produce aggregates and rock filling material at Catalagzi region at Zonguldak province in Turkey. However, there are some structures which can be adversely affected by blasting at the quarry. These structures are a methane exploration drill hole and a house at the distances of 340 and 390 m, respectively. One of the main goals of this study is to perform a preliminary assessment of possible damage effect of ground vibrations induced by blasting on these structures by risk analysis based on ground vibration measurements. In order to propose a preliminary blast design models separately for aggregate and rock filling material production, six test shots with different maximum charge per delay were planned and fired at the quarry. In these shots, 90 events were recorded. To predict peak particle velocity (PPV), the relationship between the recorded peak particle velocities and scaled distances were investigated. During this investigation, the data pairs were statistically analyzed and a PPV prediction equation specific to this site with 95% prediction line were obtained. And also, this equation was used in the derivation of the practical blasting charts specific to this site as a practical way of predicting the peak particle velocity and maximum charge per delay for future blasting. A risk analysis was performed by using this equation. In the light of this analysis, preliminary blast design models were proposed to be used in this quarry for aggregate and rock filling material production.     

Environmental impacts of bench blasting at Hisarcik Boron open pit mine in Turkey

This paper presents the results of ground vibration measurements carried out in Hisarcik Boron open pit mine located on the west side of central Anatolia near Kütahya province in Turkey. Within the scope of this study to predict peak particle velocity (PPV) level for this site, ground vibration components were measured for 304 shots during bench blasting. In blasting operations, ANFO (blasting agent), gelatin dynamite (priming), and delay electric detonators (firing) were used as explosives. Parameters of scaled distance (charge quantity per delay and the distance between the source and the station) were recorded carefully and the ground vibration components were measured for all blast events using two different types of vibration monitors (one White Mini-Seis and one Instantel Minimate Plus Model). The absolute distances between shot points and monitor stations were determined using GPS. The equation of square root scaled distance extensively used in the literature was taken into consideration for the prediction of PPV. Then, the data pairs of scaled distance and particle velocity obtained from the 565 event records were analyzed statistically. At the end of statistical evaluation of the data pairs, an empirical relation which gives 50% prediction line with a reasonable correlation coefficient was established between PPV and scaled distance.     

Environmental impacts of ground vibration induced by blasting at different rock units on the Kadikoy–Kartal metro tunnel

This paper presents the results of ground vibration analysis induced by blasting during the construction of the Istanbul Kadıköy–Kartal metro tunnel. Different rock formations in this tunnel route were encountered during the excavation with blasting. As a first stage, the test site is divided into 6 main regions with respect to lithology changes in the rock units and Hoek's Geological Strength Index value of these rock units. During the excavation, a total of 659 events were recorded in 260 shots by vibration monitors. Scaled distance and peak particle velocity data pairs belonging to these shots were carefully recorded and analyzed statistically. As a result of this analysis, empirical relationships between scaled distance and peak particle velocity were established with higher correlation coefficients specific to each region. Finally, the particle velocities and frequency values of all blast events were evaluated according to Turkish Environmental Regulation, the United States Bureau of Mines (USBM) and the German DIN 4150 Norms in order to predict the influence level to the neighboring buildings and structures.     

地下洞室边墙爆破振动传播衰减规律研究

基于桃花嘴矿区地下洞室爆破振动现场试验的实测数据,发现了地下洞室爆破开挖诱发边墙质点峰值振动速度传播衰减的特点,即爆源近区和边墙中心区域具有更大的放大效应。建立了四边简支板的动力学模型,进一步结合量纲分析法,推导出考虑边墙四边约束的地下洞室爆破边墙质点峰值振动速度预测公式。将实测数据分别代入萨道夫斯基公式和推导公式进行线性回归运算,得到萨道夫斯基公式预测值和推导公式预测值的平均误差分别为30.7%和5.1%。结果表明,该公式能较准确地反映地下洞室爆破边墙质点峰值振动速度存在的放大效应,特别可以精确预测放大效应显著区域的爆破振动峰值速度,为更好地控制边墙爆破振动损伤提供了参考价值。     

Prediction of ground vibrations resulting from the blasting operations in an open-pit mine by adaptive neuro-fuzzy inference system

The aim of this study is to predict the peak particle velocity (PPV) values from both presently constructed simple regression model and fuzzy-based model. For this purpose, vibrations induced by bench blasting operations were measured in an open-pit mine operated by the most important magnesite producing company (MAS) in Turkey. After gathering the ordered pairs of distance and PPV values, the site-specific parameters were determined using traditional regression method. Also, an attempt has been made to investigate the applicability of a relatively new soft computing method called as the adaptive neuro-fuzzy inference system (ANFIS) to predict PPV. To achieve this objective, data obtained from the blasting measurements were evaluated by constructing an ANFIS-based prediction model. The distance from the blasting site to the monitoring stations and the charge weight per delay were selected as the input parameters of the constructed model, the output parameter being the PPV. Valid for the site, the PPV prediction capability of the constructed ANFIS-based model has proved to be successful in terms of statistical performance indices such as variance account for (VAF), root mean square error (RMSE), standard error of estimation, and correlation between predicted and measured PPV values. Also, using these statistical performance indices, a prediction performance comparison has been made between the presently constructed ANFIS-based model and the classical regression-based prediction method, which has been widely used in the literature. Although the prediction performance of the regression-based model was high, the comparison has indicated that the proposed ANFIS-based model exhibited better prediction performance than the classical regression-based model.     

基于灰色关联分析的遗传神经网络在水下爆破中质点峰值振动速度预测研究

水下爆破是一个复杂的、非线性的动态能量释放过程,其涉及到的影响因素众多。为了充分利用少量的实测数据,较准确地预测水下爆破质点峰值振动速度,引入灰色关联分析理论,并结合遗传神经网络较强的非线性映射优势和全局化的搜索能力,建立基于灰色关联分析的遗传神经网络模型(GRA-GA-BP)。该模型利用灰色关联分析理论,充分挖掘小样本潜在信息特征,较合理地确定了影响爆破振动速度的主要因素,解决了神经网络在多变量复杂系统中输入变量无法自动寻优的难题,从而增强了神经网络的适应能力和稳定性。采用该模型对广东台山核电站1期工程大襟岛水下爆破开挖质点峰值振动速度进行预测,并与传统的遗传神经网络及萨道夫斯基公式预测结果进行对比,发现GRA-GA-BP模型的预测值与实测值吻合更好,预测误差更稳定。研究方法可为小样本、多因素影响下类似工程质点峰值振动速度预测提供借鉴。     

Environmental impact of blasting at Drenovac limestone quarry (Serbia)

In present paper, the blast-induced ground motion and its effect on the neighboring structures are analyzed at the limestone quarry "Drenovac" in central part of Serbia. Ground motion is examined by means of existing conventional predictors, with scaled distance as a main influential parameter, which gave satisfying prediction accuracy (R > 0.8), except in the case of Ambraseys–Hendron predictor. In the next step of the analysis, a feed-forward three-layer back-propagation neural network is developed, with three input units (total charge, maximum charge per delay and distance from explosive charge to monitoring point) and only one output unit (peak particle velocity). The network is tested for the cases with different number of hidden nodes. The obtained results indicate that the model with six hidden nodes gives reasonable predictive precision (R ≈ 0.9), but with much lower values of mean-squared error in comparison to conventional predictors. In order to predict the influence level to the neighboring buildings, recorded peak particle velocities and frequency values were evaluated according to United States Bureau of Mines, USSR standard, German DIN4150, Australian standard, Indian DMGS circular 7 and Chinese safety regulations for blasting. Using the best conventional predictor, the relationship between the allowable amount of explosive and distance from explosive charge is determined for every vibration standard. Furthermore, the effect of air-blast overpressure is analyzed according to domestic regulations, with construction of a blasting chart for the permissible amount of explosive as a function of distance, for the allowable value of air-blast overpressure (200 Pa). The performed analysis indicates only small number of recordings above the upper allowable limit according to DIN4150 and DMGS standard, while, for all other vibration codes the registered values of ground velocity are within the permissible limits. As for the air-blast overpressure, no damage is expected to occur.     

岭澳核电站二期工程基岩爆破安全阈值分析

核电站基础爆破开挖过程中必须严格控制岩体爆破损伤深度,确保建基面安全。以广东岭澳核电站二期工程基础爆破开挖为例,通过现场爆破振动监测、岩体声波试验以及数值模拟,综合分析了岩体爆炸振动衰减规律和损伤特征,研究了距爆源一定距离处岩体振动速度与损伤特征的关系,提出了岭澳核电站二期工程岩体爆炸损伤深度的控制方法,确定了相应的安全阈值。分析结果表明,岭澳核电站二期工程基础爆破开挖时,当距爆源30 m处的岩体质点振动速度不超过5 cm/s时,可保证下卧基岩的损伤深度小于2 m,确保建基岩完整性。     

铁路隧道近距离下穿楼房控制爆破试验研究

结合内水－昆明铁路盐津1号隧道下穿楼房的实际情况,借助试爆和振动监测手段,对铁路隧道近距离下穿楼房应采用的爆破方法进行了研究。结果表明,在现场进行爆破设计所得的爆破参数是合理的,有利于近接隧道工程的成功修建;近接地下工程的修建中,在重难点工程施工前,现场进行爆破试验和振动监测是确保工程成功修建的有效手段;干扰减振爆破技术有着巨大的利用空间,随着爆破技术及爆破器材的发展,在将来的控制爆破中将发挥不可估量的作用。     

爆破振动对砂浆锚杆的影响研究

爆破振动对锚杆有不利影响,运用应力波理论,并利用波函数展开法,研究了爆炸应力波与锚杆的相互作用过程,给出了爆破振动作用下砂浆锚杆周围砂浆体中的动应力和峰值振速分布情况,比较了不同频率应力波对锚杆的影响,导出了不同频率应力波作用下砂浆锚杆的安全质点振速范围。研究结果表明：入射波频率越高,砂浆锚杆所允许的安全质点峰值振速越大。     

Evaluation of initiating system by measurement of seismic energy dissipation in surface blasting

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.     

凹形地貌对爆破振动波传播影响的数值模拟

应用UDEC程序模拟了爆破振动波在凹形地貌中的传播特征,并与广东岭澳核电站2期基础爆破开挖现场监测结果进行了对比。对比分析结果表明,数值模拟结果与现场监测结果较为吻合。研究结果还揭示,凹形地貌对爆破振动波具有明显的衰减作用,质点水平向振动速度的衰减幅度大于质点垂直向。同时,衰减系数随凹形地貌深度、宽度的增加而增加,但随宽度增加的幅度较小。另外,爆破振动波的衰减系数随爆源距增加而减小,随最大段药量的增大而增大。     

台山核电站边坡爆破振动监测及数值模拟研究

台山核电站场平一期边坡的稳定性直接关系到电站的顺利建设及核电站运营期间的安全。通过现场爆破振动监测,分析了爆破开挖时边坡的振动速度衰减规律, 发现爆区上方马道内侧质点振动速度随高程增加存在放大效应,并且这种放大效应在水平径向比垂直向更为显著;另外,在爆区上方第1级马道内侧,质点垂直向振动速度一般比水平径向振动速度大,平均为其1.5倍左右,而后随着应力波向坡体传播,垂直向速度迅速衰减,而水平径向速度衰减相对较慢,到第3级马道内侧,质点水平径向速度已和垂直向持平或略大。同时,结合三维离散元数值软件(3DEC)进行数值模拟,对边坡在爆破荷载作用下质点振动速度、位移以及塑性区状态进行分析,并与现场监测结果进行比较。结果表明,数值计算值与实测值误差在15%以内;在爆破荷载作用下边坡各级马道外侧顶点产生永久位移,但均较小,且趋于稳定;塑性区仅限于爆区周围,边坡整体是稳定的     

小间距隧道爆破动力特性试验研究

分岔隧道是一种新型隧道结构形式。以漆树槽分岔隧道为工程背景,进行了掘进爆破的围岩震动效应试验,通过不同掏槽结构下爆破震动作用隧道围岩衬砌质点振动速度的频谱分析与质点振动速度幅值的分布情况分析,对小间距公路隧道混凝土衬砌及其围岩在爆破地震波作用下的力学特征进行论述,重点研究了小间距隧道中隔墙及爆破掌子面的震动特性及变化规律。试验与分析结果表明,（1）中墙迎爆侧为振速峰值区,以水平径向振速最大,且沿着中墙走向呈现规律性变化;（2）掏槽孔爆破产生的地震效应最为强烈,其震动强度是扩槽眼和周边眼的2倍左右;（3）衬砌振速主振频率主要分布在低频段,以20～95 Hz为集中频段,高频地震波衰减极快;（4）同一测试断面中最大振速峰值出现在拱顶和边墙中部位置的概率最大,且大小比较接近,爆破掌子面附近的振速不适合萨道夫斯基预测公式,受爆破夹制及自由面的影响较大。     

超小净距隧道爆破振动现场监测及动力响应分析研究

以南京地铁超小净距隧道为工程背景,结合国内外现有研究成果和规范,研究确保小净距先行隧道安全稳定的后行隧道爆破施工控制技术。以现代信息化施工理论为依据,充分运用现场监控量测,对先行隧道爆破质点振动速度进行监测分析和施工中爆破采用减振和隔振两方面控制技术;最终现场监测结果表明,优化后的循环进尺、段最大装药量与分段爆破差等爆破参数设计合理,该爆破设计在施工中未对先行隧道安全产生较大影响;同时,通过三维数值模拟计算,得到先行隧道壁面的质点振动速度随时间的变化规律,所得最大振速符合规范要求,也再次验证了优化后的爆破设计是合理的。通过数据分析得出隧道边墙的切向和径向振速比拱脚相应振速大,爆破面前方先行洞衬砌受爆破振动的影响稍大于后方衬砌,临近爆破点的左线隧道衬砌表面振动大于远离爆破点的衬砌表面振动。该研究成果为本工程施工提供了科学依据与技术指导,也可为类似隧道工程的爆破掘进工程在理论和施工方法上提供参考借鉴。     

Multivariate statistical analysis approach for prediction of blast-induced ground vibration

Excavation of coal, overburden, and mineral deposits by blasting is dominant over the globe to date, although there are certain undesirable effects of blasting which need to be controlled. Blast-induced vibration is one of the major concerns for blast designers as it may lead to structural damage. The empirical method for prediction of blast-induced vibration has been adopted by many researchers in the form of predictor equations. Predictor equations are site specific and indirectly related to physicomechanical and geological properties of rock mass as blast-induced ground vibration is a function of various controllable and uncontrollable parameters. Rock parameters for blasting face and propagation media for blast vibration waves are uncontrollable parameters, whereas blast design parameters like hole diameter, hole depth, column length of explosive charge, total number of blast holes, burden, spacing, explosive charge per delay, total explosive charge in a blasting round, and initiation system are controllable parameters. Optimization of blast design parameters is based on site condition and availability of equipment. Most of the smaller mines have predesigned blasting parameters except explosive charge per delay, total explosive charge, and distance of blast face from surface structures. However, larger opencast mines have variations in blast design parameters for different benches based on strata condition: Multivariate predictor equation is necessary in such case. This paper deals with a case study to establish multivariate predictor equation for Moher and Moher Amlohri Extension opencast mine of India. The multivariate statistical regression approach to establish linear and logarithmic scale relation between variables to predict peak particle velocity (PPV) has been used for this purpose. Blast design has been proposed based on established multivariate regression equation to optimize blast design parameters keeping PPV within legislative limits.     

Evaluation of ground vibrations and the effect of air blast in open-pit phosphate mines

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.     

上下交叉隧道爆破振动控制技术研究

钻爆法是隧道开挖中一种主要的施工方法,爆破开挖不可避免会对围岩产生扰动。以新建走马岗隧道上穿东深供水走马岗引水隧洞工程为背景,开展上下交叉隧道爆破振动控制技术研究。选取与交叉段岩性一致的爆破施工开挖区域进行爆破振动监测,得到了现场爆破施工方案条件下走马岗隧道爆破振动规律。对实测数据进行回归分析,计算得出走马岗地区爆破质点峰值振动速度（PPV）的Sadovsk公式,反演得到控制爆破振动的最大掏槽药量及安全距离,制定出交叉段施工的安全控制范围以及相应的爆破方案。通过数值模拟进行了验证并付于交叉段现场施工。现场监测数据表明,提出的振速控制标准及爆破方案符合安全要求,保证了在建隧道的顺利开挖以及既有隧道的安全运行。研究成果可为类似工程爆破开挖及振动控制提供参考。     

Prediction of blast fragmentation using multivariate analysis procedures

An extensive multivariate analysis procedure for prediction of blast fragmentation distribution is presented. Several blasts performed in various mines and rock formations in the world are brought together and evaluated. Blast design parameters, the modulus of elasticity, in situ block size are considered to perform multivariate analysis. The hierarchical cluster analysis is used to separate the blasts data into different groups of similarity. Group memberships were checked by the discriminant analysis. The multivariate regression analysis was applied to develop prediction equations for the estimation of the mean particle size of muckpiles. Two different prediction equations were developed based on the rock stiffness. Validation of the proposed equations on various mines is presented and the capability of the prediction equations was compared with one of the most applied fragmentation distribution models appearing in the blasting literature. Prediction capability of the proposed models was found to be strong. Diversity of the blasts data used is one of the most important aspects of the developed models. The models are not complex and suitable for practical use at mines. Copyright © 2010 John Wiley & Sons, Ltd.     

爆破开挖对岩体含水裂纹扩展的扰动机制

岩体裂纹的水力劈裂是岩体开裂渗漏甚至施工涌水的重要影响因素之一,也是岩土工程界的研究热点。从断裂力学角度分析了爆破开挖对岩体含水裂纹扩展的扰动作用,结果表明,爆破开挖扰动下,岩体含水裂纹的扩展,与爆炸应力波强度及其入射角、地应力的大小与方向、孔隙水压大小、裂纹的倾角及断裂韧度等因素相关;爆炸应力波的作用,相当于增大了岩体裂纹中的孔隙水压力,每1 cm/s的峰值振动速度相当于增大100 kPa的孔隙水压力,爆破振动速度越大,所产生的爆破扰动荷载越大;岩体开挖引起的岩体裂纹近区地应力及其孔隙水压力的变化,对裂纹的失稳与扩展具有较复杂的影响,可改变裂纹的失稳扩展模式。