深埋高应力区卸压松动爆破确定合理孔径的研究

针对平煤十一矿回采工作面卸压爆破合理孔径确定问题,基于实验室测定工作面的煤岩体材料参数,结合实际工况,用分析软件LS-DYNA分别对孔径30 mm、40 mm、60 mm和80 mm工况的区卸压松动爆破进行数值模拟。数值模拟结果表明:四种工况下,裂隙半径最大为1.211 m;最大主应力历程曲线随着孔径的增大,爆破作用时间明显增大。通过裂隙半径结合最大主应力分析,得出该煤矿卸压爆破合理孔径为60 mm;根据确定的爆破孔径在现场进行效果考察,工作面前方的应力集中区向深部转移;消除了工作面前方局部应力集中现象。     

节理裂隙岩体爆破试验研究

首先利用超声波探测法对节理裂隙岩体进行了声波测试,对不同的节理裂隙岩体进行了质量评估.然后通过对节理裂隙岩体进行爆破漏斗试验,分析了节理裂隙对岩体中爆炸应力波传播、岩石破碎及爆破漏斗形成的影响,得出了一些有益结论,对节理裂隙岩体理论研究和指导工程实践具有一定的参考价值.     

爆破载荷下隧道围岩破坏裂隙范围研究

为确定爆破载荷作用下岩体的裂隙范围，应用摩尔-库伦强度准则确定岩石在冲击波作用下的粉碎区；在考虑粉碎区范围、应力波衰减指数改变和岩石三向受力状态的情况下,用Mises强度准则计算裂隙区范围；在不考虑爆生气体在应力波形成的裂隙区损失的前提下，用岩石的断裂韧性来计算爆生气体充满粉碎区后岩石裂隙的二次扩展范围。通过理论计算与现场声波实测值对比，理论计算值比实测值小8.45%。分析表明，该裂隙范围计算方法合理，并可以对类似工况的裂隙范围进行估算。     

考虑裂隙岩体爆破损伤的装药结构研究

装药结构是改善裂隙岩体爆破效果的重要因素,结合某隧道爆破掘进工程,通过地质雷达现场岩体损伤探测及柱状装药爆破损伤理论估算,获取隧道掌子面前部裂隙岩体爆破损伤规律,并提出基于其爆破损伤规律的装药结构。雷达探测发现:隧道掌子面前部裂隙岩体受爆破开挖损伤明显,Ⅳ级岩体的裂隙区范围最大值约2.4 m,Ⅲ级岩体为1.8 m,均位于下一装药区域内,理论计算与雷达探测结果基本一致。利用获得的掌子面前方裂隙岩体的爆破损伤规律,提出了"减药非连续装药"装药结构,可减少裂隙区炮孔二分之一装药量。实践证明:该装药结构能提高爆破有效能,降低工程成本与围岩损伤。     

爆破漏斗形成过程数值模拟的几个关键问题

合理准确地再现爆破漏斗的形成过程对爆破模拟及工程设计具有重要意义。通过设置人工节理,将模型进行预先离散,在离散元程序3DEC中实现了半无限介质中爆破模拟,包括从炮孔扩张、裂隙发展、岩块飞散到爆堆成型的全过程。讨论了爆炸荷载简化、施加方式和离散方法等对岩石爆破破碎、抛掷及爆堆形成过程的影响。其中对人工节理的倾角和分布进行了重点研究,通过优化人工节理方向,使得模拟结果更符合实际。将爆破块度与岩体离散化结合,提出考虑爆破块度的3DEC人工离散方法,提高了模拟结果的精度。采用该模型与现场试验进行比较,模拟得到的漏斗底半径及深度与试验结果相符。并且该模型大幅度提高计算速度和计算稳定性,可广泛应用于生产实践中,为爆破设计提供参考。     

现场混装乳化炸药在地下铁矿的爆破漏斗试验及应用

针对杏山铁矿在掘进作业中“自动化减人、机械化代人”的技术需求，研制了乳化炸药现场混装设备用于掘进爆破。由于混装炸药与传统卷药在装药结构与敏化方式上的显著区别，为获取有效的爆破参数，根据利文斯顿爆破漏斗理论，制作混装炸药药包，对爆后形成的爆破漏斗半径进行测量并利用3D建模获得漏斗体积。通过爆破漏斗试验，得到了该类炸药在杏山铁矿矿岩区的爆破漏斗最佳埋深比为0.584,应变能系数为1.20 m/kg^1/3,当孔内装药量为4 kg时，炮孔间距不宜超过1.13 m等技术参数，并应用于指导掘进爆破作业的参数设计。研究表明，爆破漏斗试验为杏山铁矿的掘进作业提供了有效的技术支撑。     

平行密集束状深孔高效爆破技术研究及应用

近年来,北京矿冶研究总院在深入开展束状孔爆破理论与技术研究的基础上,创新性地开发了束状孔当量球形药包爆破技术与束状孔变抵抗线爆破技术,并广泛应用于不同条件地下矿山的开采中,取得了良好的效果。本文结合冬瓜山铜矿和华锡集团铜坑矿地下开采工程,介绍了上述两项爆破技术的原理、特点、实际应用效果与扩展领域,具有一定的学术与应用价值。     

应力波和爆生气体共同作用下裂隙区范围研究

为了得到更加符合实际的裂隙区范围计算公式,从理论上分析研究了在空气不耦合装药条件下裂隙区范围的计算方法。选取2号岩石乳化炸药和4种典型的岩石参数值,对基于初始损伤和粉碎区存在的岩石裂隙区半径进行了计算,并在此基础上运用阿贝尔原理和岩石止裂条件考虑了爆生气体准静态作用下裂隙的二次扩展。研究结果表明:粉碎区范围的大小会对裂隙半径极大值产生较大影响,并且当岩石初始损伤达到0.7~0.8时,裂隙区半径受到的影响程度达到最大;得到了应力波动作用和爆生气体准静态作用下裂隙区半径计算公式。     

单自由面垂直炮孔爆破残孔长度研究

在分析单自由垂直炮孔装药爆破作用特性的基础上,探讨了残孔形成的机理,进行了单自由面垂直炮孔装药的爆破漏斗模型试验。研究结果表明：由于炮孔深部岩石的夹制作用,炮孔装药爆破后易产生一定量的残孔,而采用孔内装药分段微差爆破则能减少残孔长度,提高爆破效率。     

平行密集束状深孔高效爆破技术研究及应用

近年来,北京矿冶研究总院在深入开展束状孔爆破理论与技术研究的基础上,创新性地开发了束状孔当量球形药包爆破技术与束状孔变抵抗线爆破技术,并广泛应用于不同条件地下矿山的开采中,取得了良好的效果。本文结合冬瓜山铜矿和华锡集团铜坑矿地下开采工程,介绍了上述两项爆破技术的原理、特点、实际应用效果与扩展领域,具有一定的学术与应用价值。     

Solution of periodic group circular hole problems by using the series expansion variational method

This paper investigates the periodic group circular holes composed of infinite groups with numbering from j = ? ∞, …, ?2, ?1, 0, 1, 2, … to j = ∞ placed periodically in an infinite plate. The same loading condition and the same geometry are assumed for holes in all groups. The series expansion variational method (SEVM) is used for the solution of the periodic group circular hole problems. After using the SEVM, the boundary value problem is then reduced to an algebraic equation for the undetermined coefficients in the series expansion form, which is formulated on the central group. The influences on the central group from central group itself and many neighbouring groups are evaluated exactly. The influences on the central group from remote groups from j = ? ∞, ?(M + 2), ?(M + 1), M + 1, M + 2 to j = ∞ are approximately summed up into one term. This suggested technique is called the remainder estimation technique (RET) hereafter. It is proved from the computed results that the RET is very effective for the solution of the periodic group hole problems. Finally, several numerical examples are given and the interaction between the groups is addressed. Comparison between various sources of computation is presented. In the uniaxial tension in y‐direction, the stacking effect of the stacked groups is studied. Copyright © 2006 John Wiley & Sons, Ltd.     

Determination of Stress Concentration Factors for Holes in Cylinders Using Thermoelastic Stress Analysis

Thermoelastic stress analysis is used to obtain the stress concentration factors (SCFs) from a variety of circular holes in cylinders. The cylinders are loaded in uniaxial tension, uniaxial compression and a combination of bending and compression. Firstly, radial holes are investigated and the results from the thermoelastic data obtained by the SPATE equipment are compared with previous experimental and numerical work. SCFs are then obtained from offset, oblique and offset–oblique holes using the Deltatherm system. The effect of hole obliquity and direction of applied load relative to the hole geometry are discussed in detail. Finally, the results from the cylinders are compared with predictions of the SCFs in cylinders from a previous study of oblique holes in flat plates.     

光面爆破在三峡永久船闸开挖中的应用与发展

总结了侧向保护层光面爆破在三峡永久船闸开挖中的应用,提供了水平孔和华斜孔光爆法在三峡永久船闸试验及施工的功经验数据,交光面爆破推广到任意角度。     

Analysis of the extraordinary transmission properties of arrays of subwavelength holes on a metal film in the terahertz region

The extraordinary transmission properties of terahertz waves through arrays of subwavelength holes on a metal film have been investigated. The effects of the geometrical parameters and dielectrics filling the hole on transmission properties have been explored. The results show that the resonance peak shifts to long wavelength as the hole width and lattice period constant increase. As the refractive index of the dielectric materials filling the hole increases, the transmittance increases and the resonance peak wavelength changes to low frequency. The phase retardation can be flexibly changed by varying the geometrical parameters and dielectric materials filling in the hole.     

含有任意多个椭圆孔复合材料层合板的应力场计算

本文应用各向异性弹性力学的复变函数理论,用多保角变换的方法,导出了含有任意多个任意位置椭圆孔的各向异性复合材料板的多复变量应力函数表达式,然后在单位圆周上进行复Fourier级数展开,用待定系数法确定应力函数的未知系数,从而计算弹性板的应力场.编制了相应的多工况运行的FORTRAN77标准化程序,进行了考题和算例分析,给出了级数的收敛状况和孔边周向应力的分布图.      

Range of Applicability of the Method of Caustics around Holes

Abstract:  The range of applicability of the optical method of caustics, which is based on plane stress conditions, around cylindrical holes in plane specimens is investigated. The position of the generatrix curve of the caustic and the conditions, which influence its size, are defined. The dimensions of the specimen, the ratio of the thickness to the diameter of the hole, the applied stress and the dimensions of the optical set-up influence the position of the generatrix curve of the caustic. At a critical distance from the boundary of the hole the state of stress degenerates from three-dimensional to plane stress. In this paper, the extent of this region was defined by finite element analysis, in case of uniaxial tension. The defined critical distance was correlated with the condition, which influence the caustic, thus the range of applicability of the method of caustic around hole was defined. The validity of this range was experimentally checked.     

掏槽爆破在采场中部掘沟中的应用

介绍了采场中部掏槽破在峨口铁矿的应用,提供了一级比较合理的爆破参数,供数似矿山的生产作参考。     

筒车坝电站导流隧洞开挖工程的教训与经验

介绍了筒车坝电站导流隧洞爆破开挖工程施工的教训与经验,指出控制爆破技术的掌握是争创优质爆破开挖工程的前提,良好的施工组织管理是争创优质爆破开挖工程的保障。     

瓦楞纸箱提手孔位置对抗压强度的影响

对同一规格、不同开孔位置的某重型装饰灯具外包装瓦楞纸箱进行了抗压强度的试验,以探讨提手孔位置对纸箱抗压强度的影响。在瓦楞纸箱侧面中线上方H/6以内的高度进行四等分,得到实验的4个测试点,以此4点为中心开取弧型提手孔,分别对其进行空箱抗压强度测试。结果表明:纸箱侧面开孔后,纸箱的抗压强度会降低;当提手孔开孔位置处于箱面中线上方H/18高度时,抗压强度损失最小。     

Roles of photo-generated holes and oxygen vacancies in enhancing photocatalytic performance over CeO2 prepared by molten salt method

A series of CeO₂ photocatalysts were synthesized through the molten salt method. The photocatalytic activity was evaluated through the degradation of methyl orange (MO). Systematic characterizations including X-ray diffraction, Scanning electron microscopy, Fourier transformed infrared, X-ray photoelectron spectroscopy, Raman spectroscopy, electron spin-resonance spectroscopy, UV–vis diffuse reflectance spectroscopy, photoluminescence spectrometry, photocurrent response and electrochemical impedance spectroscopy were conducted to study the as-prepared CeO₂ samples. It was found that, under ultraviolet light irradiation, the apparent rate constants of CeO₂ prepared at 800 °C for degradation of MO was about 3.4 times higher than CeO₂ prepared at 500 °C. CeO₂ prepared at 800 °C held the higher oxygen vacancies concentration. According to the trapping experiments, it was demonstrated that photo-generated holes played a dominant role in this photocatalytic system. Furthermore, the possible photocatalytic mechanism which showed the roles of photo-generated holes and oxygen vacancies was proposed.