水不耦合炮孔装药爆破冲击波的形成和传播

探讨了炮孔和装药间以水不耦合介质爆破时,在爆轰波压力和高压、高温爆生气体压力作用下,水中爆炸冲击波的形成和传播规律,求解了冲击波的初始参数和孔壁处冲击波参数,并应用弹性波动理论,提出了正入射情况下岩石内的初始冲击压力。     

不耦合装药下爆炸应力波传播规律的试验研究

通过室外爆破试验,利用预埋研制的PVDF压力传感器对耦合及水不耦合延长药包装药爆破时爆炸应力波的中远场压力进行测量,拟合实测结果,得到4种不耦合系数下爆炸应力波峰值随传播距离衰减的指数关系式。分析试验结果可知： ①在试验所涉及的范围内,不耦合装药时爆破应力波峰值衰减幅度小于耦合装药（即K =1）时爆破应力波峰值衰减幅度,验证了水介质作为炸药爆轰产物与岩体间的弹性缓冲层作用,减少了粉碎孔壁岩体造成的能量耗散,增加了能量传递,加大了爆炸的作用范围;②当不耦合系数K = 3.29时,应力波峰值衰减指数表现出大于K =1.79及大于K =2.57时应力波峰值衰减指数的趋势,表明过大的不耦合系数造成了不耦合介质--水过多的能量耗散（在高温高压下水并不完全是弹性的）,削弱了不耦合装药爆破的优势;③在不耦合装药爆破中,存在最佳的不耦合系数,此时爆炸应力波峰值衰减最慢,爆炸能得到充分利用,达到最优的爆破效果。研究结果对不耦合装药爆破的设计及工程应用有一定的指导意义。     

工程爆破中径向水不耦合系数效应数值仿真

在实际工程爆破中,水不耦合炮孔是较常见的,其中水不耦合装药系数是影响爆破效果的关键因素之一。该系数取不同的值,将产生不同的应力波传播机理以及介质的损伤破坏程度。以往的研究主要集中于理论解析法和模型试验法。基于大型非线性动力分析软件LS-DYNA,采用著名的混凝土损伤Johnson-Holmquist-Concrete模型,针对无限混凝土介质水不耦合装药爆破中不同径向耦合系数Kd,展开了对比数值计算,综合分析了损伤破坏区分布和孔壁压力、加速度以及速度等与径向不耦合系数间的关系,得出的结论具有一定的参考价值。     

岩石爆破过程S波的产生机制分析

全面总结、分析了岩石爆破过程S波的产生机制,表明短柱状药包、炮孔周围岩体的开裂与破碎以及装药偏离球形或柱形空腔中心,均可诱发S波,并且诱发S波的幅值可超过P波;P波传播过程与岩体界面的相互作用,可产生次生的S波（透、反射SV波）。在此基础上,就爆破振动场模拟方法与计算模型选择中如何体现S波的产生机制方面提出了建议     

岩体软硬度对一维应力波演化影响研究

地下球形药包爆轰后将产生很强的地震波．其传播受多种因素的影响。本文把岩石介质的弹塑性帽盖模型耦合到有限差分法程序中，对一维爆轰波在非均质岩石体中的传播、演化机理进行了数值模拟与分析。着重探讨一维应力波从“硬”岩石层进入“软”岩石层、从“软”岩石层进入“硬”岩石层时，波在形状和强度等方面的变化规律。同时也探讨了岩石介质中存在的“软弱夹层”对一维应力波传播的影响。这些对于人防工程等中的波阻抗的功能梯度效应和智能防护等方面的研究具有一定的参考价值。     

论分段药包间砲泥的作用

在使用分段装药的爆破工作中,(石包)眼内药包传爆距离主要是决定于中间介质((石包)泥)的性质,在第二段药包中是否有起爆药象雷汞一样敏感的电雷管,以及首先爆破的药包的药量。研究中确定了通过不同介质(粘土与砂和水的混合物)的最大传爆距离。认为在     

不耦合装药爆破对硬岩应力场影响的数值分析

爆破地震勘探石油是一种重要的方法,但爆破地震效应与爆破参数、地质条件等密切相关。采用动力有限元软件ANSYS/LS-DYNA,对柱状炸药与药孔壁之间为空气或其他介质以及空隙间距变化时碳酸盐岩岩石中爆炸应力波的传播规律和爆炸地震波能量的衰减特性进行了数值模拟研究,得到了不耦合装药爆炸时岩石应力、振动速度的衰减规律以及与不耦合系数、间隙介质的关系,分析了不耦合效应对爆炸地震波能量的影响。研究表明,不耦合或耦合不好时会使岩体中爆炸应力波的强度大大降低;耦合状态对岩体应力及速度的衰减系数和衰减指数影响较大;在空隙中注水或灌满泥浆会改善它们的耦合关系,增大下传的爆破能量。所得成果可为我国西南地区优选适合碳酸盐地层地震勘探的激发因素提供技术途径和方法。     

岩体爆生裂纹的数值模拟

利用广东岭澳核电站现场角岩岩体的基本动态力学特性和爆破参数,以及材料的Von Mises破坏准则,通过ANSYS/ LS-DYNA程序模拟了岩体单孔柱状装药的爆破破裂过程,分析了岩体爆破裂纹产生和扩展的机制,得到了岩体粉碎区和裂隙区的范围以及爆源近区岩体质点峰值压力的衰减规律。研究结果表明,岩体爆破粉碎区半径约为装药半径的6.5倍,裂隙区的半径约为装药半径的75倍,炸药起爆时粉碎区形成时间很短,大约为80 μs,而裂隙区的完全形成则需要较长的时间。     

岩石中柱状装药爆炸能量分布

岩石中装药爆炸产生的爆破能量可分为爆炸冲击波能量和爆生气体膨胀能量。对爆炸能量分布的理论分析有助于改善爆破效果,提高爆破质量。在柱状耦合装药情况下,分析了冲击波作用下岩石变形和破坏的特点、爆生气体对爆腔的扩腔作用,考虑了在岩体的损伤情况下爆生气体对裂纹的驱裂作用。计算结果表明：埋深在临界深度以下时,岩石中柱状装药爆破冲击波做功消耗的能量约占爆炸总能量的40 %,剩余爆生气体能量中用于扩腔和扩展主要裂隙的能量约占总能量的23 %,剩余大约37 %的能量中有小部分能量用于新增裂纹数目,而大部分损失掉了。     

条形药包在隧道爆破中产生的应力场的实测分析

基于条形药包的爆破特性,针对隧道爆破的装药形式,把隧道爆破简化成几个条形药包的微差爆破,在隧道爆破区域的径向应力波为柱形,隧道掘进的轴向应力波为几个并列半圆形。应力波强度分布很不均匀,爆破区域的径向应力强度最大,向爆区端部延伸径向应力强度逐渐减小。进入爆区端部后,应力强度减小更明显。随着与爆区轴线夹角的减小,端部应力强度再次减小,爆区端部轴线方向应力强度最小。     

A solution for the transition zone isosats in two-phase primary drainage in the presence of gravity

Primary drainage in a water-wet saturated medium in the absence of capillarity is typically a combination of shock (discontinuous) and rarefaction (continuous) waves. Using nonlinear relative permeability functions for the host fluid and the invading fluid leads to the existence of a shock wave front, and the degree of nonlinearity of the relative permeability functions has an inverse relationship with the size of the shock wave (i.e., difference of saturation between upstream and downstream of the shock wave), whereas for linear relative permeability functions, the shock wave size approaches 0. Injection of a lower-viscosity immiscible phase such as gas or solvent into a water-wet porous medium in the presence of large capillary pressure leads to development of an extended and growing saturation transition zone that follows the discontinuous shock wave front. In this article, a semianalytical solution for the position of equisaturation contours (isosats) in the transition zone in the presence of gravity is obtained for a set of linearized relative permeability functions. The capillary (diffusive) and buoyancy terms are neglected, and the generalized convective equation for mass conservation is obtained. The set of equations is then reduced to a one-dimensional steady-state differential equation through forcing the isosat formulation to obey mass conservation. This scheme allows the isosat distribution to be solved, and the case of injection into an axisymmetric geometry for a confined planar configuration is solved and presented. A finite element model was developed to demonstrate the reasonable agreement between analytical and numerical solutions.     

滑坡涌浪的产生与传播波形分析与计算

在水平匀速滑坡涌浪传播过程中,当滑坡体匀速前进时,会形成一个冲击波,停止前进后,在滑坡体与冲击波之间又形成一个稀疏波,当稀疏波追赶上冲击波时,两个波则会发生相互作用。对稀疏波与冲击波相互作用后产生的反射冲击波和入射冲击波的情况进行了定量研究。从入射冲击波的轨迹方程入手,通过分析和计算,分别得到了入射冲击波和反射冲击波波高、波速等一些定量的关系式,并用简单的计算方法进行了求解。     

可压缩流体饱和孔隙介质中孔隙压力波传播数值分析

首次将高精度时空守恒元/解元方法推广到可压缩流体饱和孔隙介质中孔隙压力波传播的数值计算中。将孔隙度梯度从源（汇）项中分离,直接引入流通量,改进了理论模型。通过对孔隙介质激波问题的数值模拟,验证了方法的精度和有效性。在此基础上,提出了孔隙介质中二维黎曼问题,并揭示了孔隙压力波存在接触间断、激波、膨胀波、压缩波等复杂的结构特征。该成果对二氧化碳地质封存、二氧化碳提高石油采收率、页岩气压裂开采以及地震破裂过程的研究具有重要的理论与应用意义。     

有耗介质探地雷达波传播衰减特性的研究

探地雷达是利用超高频脉冲电磁波探测地下介质分布的一种浅层地球物理勘探方法,探地雷达超高频、宽频带脉冲电磁波在地下有耗介质中的衰减特性是一个十分复杂的过程。本文从电磁波传播的麦克斯韦方程出发,较为系统地研究和分析了雷达脉冲电磁波在有耗介质中传播的衰减特性,对研究雷达脉冲电磁波在地下有耗介质中的传播机制有指导意义。     

Propagation of Rayleigh waves in unsaturated porothermoelastic media

Based on the frame of elastic theory for unsaturated porous medium, considering the influence of thermal effect, the propagation characteristics of Rayleigh wave in unsaturated porous media are studied. Firstly, the thermoelastic wave equations for three-phase porous media are established, in which the mass balance equations, generalized Darcy law, momentum balance equations, and generalized non-Fourier heat conduction law are taken into account. Secondly, through theoretical derivation, the dispersion equation of Rayleigh wave for unsaturated porothermoelastic media is given by introducing the potential functions. Finally, the variations of the phase velocity of Rayleigh wave are analyzed with numerical examples. The results show that the thermal conductivity has little effect on the phase velocity of Rayleigh wave. The phase velocity of Rayleigh wave increase with increasing of the thermal expansion coefficient and media temperature.     

Wave propagation in a general anisotropic poroelastic medium: Biot’s theories and homogenisation theory

Anisotropic wave propagation is studied in a fluid-saturated porous medium, using two different approaches. One is the dynamic approach of Biot’s theories. The other approach known as homogenisation theory, is based on the averaging process to derive macroscopic equations from the microscopic equations of motion. The medium considered is a general anisotropic poroelastic (APE) solid with a viscous fluid saturating its pores of anisotropic permeability. The wave propagation phenomenon in a saturated porous medium is explained through two relations. One defines modified Christoffel equations for the propagation of plane harmonic waves in the medium. The other defines a matrix to relate the relative displacement of fluid particles to the displacement of solid particles. The modified Christoffel equations are solved further to get a quartic equation whose roots represent complex velocities of the four attenuating quasi-waves in the medium. These complex velocities define the phase velocities of propagation and quality factors for attenuation of all the quasi-waves propagating along a given phase direction in three-dimensional space. The derivations in the mathematical models from different theories are compared in order to work out the equivalence between them. The variations of phase velocities and attenuation factors with the direction of phase propagation are computed, for a realistic numerical model. Differences between the velocities and attenuations of quasi-waves from the two approaches are exhibited numerically.     

Wave propagation in thermoelastic saturated porous medium

Biot’s theory for wave propagation in saturated porous solid is modified to study the propagation of thermoelastic waves in poroelastic medium. Propagation of plane harmonic waves is considered in isotropic poroelastic medium. Relations are derived among the wave-induced temperature in the medium and the displacements of fluid and solid particles. Christoffel equations obtained are modified with the thermal as well as thermoelastic coupling parameters. These equations explain the existence and propagation of four waves in the medium. Three of the waves are attenuating longitudinal waves and one is a non-attenuating transverse wave. Thermal properties of the medium have no effect on the transverse wave. The velocities and attenuation of the longitudinal waves are computed for a numerical model of liquid-saturated sandstone. Their variations with thermal as well as poroelastic parameters are exhibited through numerical examples.     

冲击载荷下块系岩体摆型波传播特性的试验研究

摆型波现象是深部开采中块系岩体固有的动力学特征之一。为研究深部块系岩体摆型波传播规律,采用理论分析与室内试验相结合的方法,研究了在冲击载荷作用下摆型波的传播特性。该试验采用12块花岗岩和橡胶夹层材料建立了模型,采用TST5915动态数据采集系统进行信号监测,分别获得了在均质夹层和部分夹层介质增厚情况下的加速度响应曲线,并运用摆型波动力模型理论进行分析。结果表明,摆型波在块体间传播过程中,频率大小不受能量大小的影响,而能量大小决定了波的衰减时间。当块体间介质黏性增加时,加速度幅值均有所下降,但对加速度衰减周期没有影响,而影响加速度衰减的主要因素是冲击载荷的能量大小。此次试验研究将为今后进一步研究摆型波动力传播特性提供一定的基础。     

On size and boundary effects in scaled model blasts—fractures and fragmentation patterns

This contribution is the third part of a paper addressing size and boundary effects on explosively induced wave propagation, fracturing and fracture pattern development in small scale laboratory specimens, which are frequently used for model blast tests. Small cylindrical and block type specimens fabricated from concrete, sandstone and amphibolite are centre-line loaded by linear explosive charges and supersonically detonated. Using shock wave theory, elastic wave propagation theory, and fracture mechanics it is shown that the type of boundary conditions prescribed at the outer boundary of the cylinder controls the extension of stem cracking and the development of the fragmentation pattern within the body of the cylinder and the cube specimens. In the case of a composite specimen, where a cylindrical core of different material is embedded in a cylinder or in a cube, the level of fracturing and fragmentation is controlled by the conditions and possible de-lamination of the interface which, in turn, depends on the relative dimensions of the core and the block. Using known results from the theory of wave interaction with free boundaries and interfaces it will be shown that the fracture strain and the notch sensitivity of the material expressed by imperfections play an important role. Equally important is the ratio between the length of the pulse (space-wise or time-wise) and the characteristic dimensions of the models. Axi-radial boundary cracks and spalling will be explained on the basis of earlier wave propagation studies associated with supersonic blasting. Theoretical results are in good agreement with numerical simulations and recent experimental findings.