共查询到20条相似文献,搜索用时 15 毫秒
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E. Widzyk-Capehart P. Lilly 《Fragblast: International Journal for Blasting and Fragmentation》2002,6(2):151-168
Blasting is the primary comminution process in most mining operations. This process involves the highly complex and dynamic interaction between two main components. The first is the detonating explosive and the second is the rock mass into which the explosive is loaded. The mechanical properties of the rock material (such as dynamic strength, tensile strength, dynamic modulus and fracture toughness) are important considerations in understanding the blasting process. However, it is the characteristics of the geological defects (joints, foliation planes, bedding planes) within the rock mass that ultimately determine how effectively a blast performs in terms of fragmentation, all else being equal. The defect characteristics include, but are not limited to, their orientation, spacing, and mechanical properties. During the blasting process, some of the geotechnical characteristics of the rock mass are substantially changed. From the blasting outcome point of view, the most notable and important is the change in fragment size distribution that the rock mass undergoes. The pre-blast in situ defect-bounded block size distribution is transformed into the post-blast muckpile fragment size distribution. Consequently, it is fundamental to our understanding of and ability to predict the blasting process that both the blastability of a rock mass and its transformation into the fragment size distribution can be appropriately quantified. 相似文献
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Yang Sen Hua Xinzhu Yang Peng Liu Xiao 《Geotechnical and Geological Engineering》2021,39(7):5161-5172
Geotechnical and Geological Engineering - In order to determine the reasonable empty roof distance during roadway excavation, a mechanical model of the direct roof rock beam was established, and... 相似文献
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External Hydrogen Index: A New Factor for Hydrocarbon Resource Assessment and its Calculation Method
<正>Objective Traditional oil and gas theory considers that hydrocarbon generation process is a hydrodeoxygenation reaction of organic matter(OM).Thus,the supply condition of hydrogen controls the hydrocarbon generation ability of OM.Those factors of TOC and hydrogen index(I_H)are playing important roles for calculating potential 相似文献
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A new damage index to estimate damage to buildings relies on construction costs per square metre, and a replacement ratio which approximates costs relative to the cost of replacing a median-sized family home. Building damage is estimated against a five-point scale with Central Damage Values at 0.02, 0.1, 0.4, 0.75 and 1.0 of the replacement cost.Damage is expressed as damage in House Equivalents (HE) = Replacement Ratio × Central Damage Value. The Damage Index = log2 (HE) provides a simple 0–20 scale covering total damage of less than 1 HE to>1 million HE. For all natural hazard impacts in Australia DI is less than 12.Where the only damage data available are of lesser quality Generic or Qualitative Damage Indices (GDI and QDI) can be used. The various advantages and limitations of the Damage Index are discussed. 相似文献
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根据施工经验,总结了在山区公路施工中开爆石方路基时,根据地形、地貌、开挖深度、断面形式和周围环境特点,所采用的不同的爆破施工方法及相关工艺参数。 相似文献
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F. Ouchterlony M. Olsson I. Bergqvist 《Fragblast: International Journal for Blasting and Fragmentation》2002,6(2):235-261
A Swedish table of blast damage depths has, in one form or other, been in use since the late-1970s. Its history and the underlying theory are described. New experimental and theoretical findings that point out a number of shortcomings in the table and the underlying theory are presented and discussed. A revised version of the blast damage table was recently introduced in conjunction with new but incomplete recommendations for cautious perimeter blasting. The new table leaves the difficult task of taking into account factory like decoupling, water in the borehole, the rock properties, type of initiation, charge length and the actual bit diameter to the user. This paper discusses different ways of doing this, based on the experimental findings and a recent formula for the prediction of the lengths of radial cracks behind the half-casts. The material presented in this paper is meant to supplement and extend the new Swedish recommendations for cautious perimeter blasting of tunnels, shafts, pits and road cuts. 相似文献
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冰川沉积物成因确定的一种新方法 总被引:3,自引:1,他引:3
冰川沉积物的成因鉴定一直存在争论,尤其是体现在讨论第四纪冰川沉积物的成因确定问题方面,传统地质学从冰川沉积物的沉积学和地貌学特征方面来讨论其成因受到了挑战,本文试图从沉积砾石中寻找与冰川成因直接相关的应用信息,进而提出用砾石的声发射应力测量法确定其冰川成因的新认识,首先对现代冰川砾石进行声发射应力测量,将此测量值丙与 石所受的实际铅直应力值比较,研究显示二者对应很好,说明冰川砾石是能够记忆上覆冰层所造成的应力,其次,无争议的第四纪冰川砾石亦具有对应的应力记录,最后讨论了有争议的庐山地区第本四冰川沉积,研 相似文献
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Blasting has been the most frequently used method for rock breakage since black powder was first used to fragment rocks, more than two hundred years ago. This paper is an attempt to reassess standard design techniques used in blasting by providing an alternative approach to blast design. The new approach has been termed asymmetric blasting. Based on providing real time rock recognition through the capacity of measurement while drilling (MWD) techniques, asymmetric blasting is an approach to deal with rock properties as they occur in nature, i.e., randomly and asymmetrically spatially distributed. It is well accepted that performance of basic mining operations, such as excavation and crushing rely on a broken rock mass which has been pre conditioned by the blast. By pre-conditioned we mean well fragmented, sufficiently loose and with adequate muckpile profile. These muckpile characteristics affect loading and hauling [1]. The influence of blasting does not end there. Under the Mine to Mill paradigm, blasting has a significant leverage on downstream operations such as crushing and milling. There is a body of evidence that blasting affects mineral liberation [2]. Thus, the importance of blasting has increased from simply fragmenting and loosing the rock mass, to a broader role that encompasses many aspects of mining, which affects the cost of the end product. A new approach is proposed in this paper which facilitates this trend 'to treat non-homogeneous media (rock mass) in a non-homogeneous manner (an asymmetrical pattern) in order to achieve an optimal result (in terms of muckpile size distribution).' It is postulated there are no logical reasons (besides the current lack of means to infer rock mass properties in the blind zones of the bench and onsite precedents) for drilling a regular blast pattern over a rock mass that is inherently heterogeneous. Real and theoretical examples of such a method are presented. 相似文献
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研究地基液化的新方法 总被引:5,自引:0,他引:5
介绍一种研究地基液化的新方法,利用地震时可能液化的土层的地面加速度,地下钻孔加速度及孔隙水压力方面的连续资料,通过计算处理,先后获得土层的水平位移反应,平均剪应变和有效应力,在此基础上,对平均剪应力-应变和有效应力路径历史作出评价,由此获得地震振动时有关地基液化过程的直接和有价值的资料。 相似文献
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在铷—锶年龄测定中,制样工作占有重要地位。要从千变万化的岩石、矿物样品中制出能满足质谱测定的Rb、Sr同位素样品,要使Rb~(87)和Sr~(87)这对同量异位素完全分离,就需要有一个简便、完备的方法。国内、外的Rb—Sr同位素实验室大都采用离子交换分离制样法。 为了满足高精度、高灵敏度及高自动化程度的 相似文献
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A Study of Optimal Rock-Cutting Conditions for Hard Rock TBM Using the Discrete Element Method 总被引:2,自引:0,他引:2
The efficiency of TBM performance affected by the specific s/p (s: spacing and p: penetration) ratio of the disc cutter is a research issue in demand. This article presents a multi-indentation simulation using discrete element method (DEM) analysis to study the optimal rock-cutting phenomena in terms of the interaction of the s/p ratio with intact rock properties. The multi-indentation simulation attempts to represent a linear cutting machine (LCM) test, which is a full-scale test for evaluating the optimal rock-cutting condition and measuring required reaction forces based on the intact rock condition in general practice. A governing equation relating mechanical rock properties with geometric characteristics for the optimal rock-cutting condition is derived by the numerical simulation, and its performance is evaluated with the result of the laboratory LCM tests. The results of simulations and real LCM tests show that the effective rock-cutting condition corresponding to the minimum specific energy can be estimated by an optimized s/p ratio, which, in turn, is linearly proportional to the square of the material brittleness, B 2, and cutter tip width, t (i.e., s/p?=?cB 2 t, where c is coefficient). The limitation of the numerical simulation associated with the sample preparation is also discussed. 相似文献
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Length distributions from sedimentary bodies can be measured in outcrop. A common feature in many outcrops is the occurrence of partially exposed bodies, i.e., sedimentary bodies that are cut by either one or both edges of the outcrop. Ignoring these partials while establishing a length distribution leads to a bias toward the smaller length classes. This is because larger bodies have a larger probability to occur as partials than smaller bodies. We present a new method for estimating the expected complete length for a partially exposed feature, based on the theory of conditional probability. The method is demonstrated and tested on a sandstone outcrop exhibiting over 200 interbedded thin silt/shale streaks. It is shown that the method can significantly enlarge both the size and the representativeness of length distributions. 相似文献
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瞬变电磁法在探测工作面顶板赋水性中的应用 总被引:4,自引:0,他引:4
瞬变电磁方法对地下水反应敏感,而矿井瞬变电磁法具备距离目标体近,分辨率高的特点。为此使用加拿大产PROTEM47瞬变电磁系统,采用共面偶极方式布置线圈,对枣庄新安煤矿3上201工作面顶板赋水性进行了探查,指出顶板以上至70m高度的范围内(510~630m段),顶板含水裂隙发育,巷道顶部存在富水异常区,并得到了钻孔放水施工验证,为工作面安全回采提供了可靠的技术支持。井下疏放水和工作面回采资料表明,瞬变电磁法探测工作面顶板赋水性具有较高的准确性。 相似文献
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页岩基质孔隙主要包含有机孔隙和无机孔隙,页岩油气在有机孔隙和无机孔隙中的渗流机理不同,对页岩中有机孔隙和无机孔隙的微观结构进行定量表征具有重要意义.首先通过扫描电子显微镜(scanning electron microscope,简称SEM)实验分别获取具有代表性的页岩无机孔隙和有机孔隙扫描电镜图像,其中,无机孔隙相对较大,其图像的分辨率较低,有机孔隙相对较小,其图像的分辨率较高;然后,通过图像处理和马尔可夫链蒙特卡洛(Markov chain Monte Carlo,简称MCMC)法重构出相应的无机孔隙数字岩心和有机孔隙数字岩心,并提出局部叠加法构建同时包含无机孔隙和有机孔隙的页岩基质孔隙数字岩心;最后对无机孔隙数字岩心、有机孔隙数字岩心和基质孔隙数字岩心的结构特征进行了对比分析.结果表明,局部叠加法构建的页岩基质孔隙数字岩心能够同时描述页岩中的无机孔隙和有机孔隙结构特征,无机孔隙本身连通性较差,有机孔隙本身连通性较好,有机孔隙的局部孔隙度和局部渗透率较高,对页岩中的流体渗流有着重要作用.该方法为页岩中不同的孔隙结构特征描述和油气在纳米尺度孔隙中的传输模拟提供了一个可靠的研究平台. 相似文献