【作者】 赵建平；

【导师】 徐国元；

【作者基本信息】 中南大学 ， 岩土工程， 2009， 博士

【摘要】 目前,由于爆炸本身的复杂性、炮孔近中区介质爆炸波测定试验设备和技术难度的限制等原因,对于岩石类介质中爆炸波作用波形基本特征及作用过程细观特征的定量研究还未见文献报道,而岩石类材料的破坏是爆炸冲击波、应力波及爆生气体膨胀三者共同作用的结果。获取爆炸波信号的试验难度使得对于岩体中爆炸波作用过程的认识大多停留在定性认识之上,缺乏对爆炸波及与爆炸波各分离量作用相关联的岩石类材料断裂损伤演化过程的定量系统研究。针对以上问题,结合教育部“优秀青年教师资助计划”课题“深井采矿爆破高效破岩及其相关灾害预防技术研究(EYTP-2134)”和教育部博士点基金资助课题“不耦合加载瞬间岩体近中区爆炸波识别及作用规律研究(200805331148)”,对岩石类介质中由爆炸激起的瞬时爆炸波特征及其作用下的岩体损伤演化过程进行了系统深入的研究。主要研究成果如下:第一,通过超动态测试系统匹配研究和实验技术改进,实现了瞬时爆炸波动应变信号的成功、稳定、重复、高效、全面测定。该应变测试系统及实验技术与其它压电或压力类传感器相比,能够测定压拉应变,使得测试数据无缺陷,波形完整,真实地反映了复杂的爆炸波作用过程,为实现炮孔近中区介质中爆炸波作用下的岩石爆破机理及岩石破岩理论的定量研究奠定了坚实的实验基础。第二,基于实测爆炸波信号及岩石破岩机理等理论,将爆炸波识别并分离为爆炸波作用一区、二区和三区,提出了与爆炸波各分离区相关联的爆炸波破岩过程。爆破破岩过程是爆炸波作用一、二区在10~4/S以上的高加卸载应变率下的压缩、再次拉伸与压缩和爆炸波作用三区准静态作用下的复杂作用过程。在空间上,三者同时存在于爆炸波有效作用范围;时间上,三者依次作用于测点,为相互独立的过程,但对混凝土的断裂损伤存在内在联系。第三,基于空气不耦合装药条件下混凝土中实测爆炸波信号识别,得到了不同不耦合系数和不同距离处爆炸波各分离区基本特征参数变化的细观特征。通过对爆炸波各分离区的应力、加卸载应变率、质点运动速度、质点加速度等基本特征进行分析,定量建立了各分离区动力学基本特征参数与不耦合系数K、到爆源中心距离R之间的关系,深刻揭示了炮孔周围介质近中区瞬时爆炸波传播及作用过程的细观特征。第四,结合前人成果,并通过自由面反射波和接触爆炸爆炸波实验实测波形与孔中爆炸波波形的比较,证实了爆炸波各分离区划分及测试数据的正确性。建立了与炸药爆轰结构、岩石破岩理论相联系的爆炸波各分离区产生机制。混凝土中的爆炸波作用一区是爆轰波前沿波阵面压缩区爆压突跃作用的结果,爆炸波作用三区是爆轰波C-J面后炸药爆轰产物等熵不定型膨胀流动的结果,而爆炸波作用二区产生复杂,可能与损伤有关。第五,针对构成瞬时爆炸波动应变各分离区信号具有短时、频带复杂、能量密度分布不均和突变快的特点,将时频能分析技术用于爆炸波信号分析,从线性和非线性时频分析技术对短时非平稳随机能量有限信号分析的适应性出发,通过多种时频分析方法对爆炸波信号的对比评价和定量计算,确定了适宜于爆炸波动应变分析的最优时频分析函数,为使用时频分析技术进行瞬时爆炸波信号分析奠定了坚实的理论和应用基础。第六,基于最优时频分析函数Rihaczek分布对不耦合装药条件下实测爆炸波信号进行时频能分析,实现了爆炸波信号在时频能三维空间上的识别定位和爆炸波时频域动应变能量密度区分离,获得了爆炸波各分离区的时频能分布特征、总动应变能和各分离区的动应变能,建立了总动应变能、各分离区的动应变能与不耦合系数K、到炮孔中心距离R的能量动态变化关系,深刻揭示了炮孔周围介质近中区瞬时爆炸波各分离区能量分配及能量中心演化的细观特征。第七,运用声波测试技术对爆炸后混凝土损伤效应进行研究,定量建立了与爆炸波各分离区基本特征参数和能量作用过程相关联的岩体体损伤累积演化机理。提出了与介质损伤阈值D_cri有关的动应变能阈值E_cri为岩体是否破裂的能量判据,根据各分离区动应变能与E_cri相比较,作为是否产生新裂纹的依据。爆炸波作用一区的作用主要体现在产生新裂纹和激活微裂纹上,而爆炸波作用二、三区的作用主要是扩展已有裂纹,并在损伤界面上存在应力及能量集中。论文获得的上述主要成果,对爆破工程、防护工程、岩体本构关系、爆炸地震波震源特性等学科的研究具有重要的理论及工程应用意义,为应用岩石类材料炮孔近中区介质瞬时爆炸波作用特征及与之作用相关联的介质断裂损伤过程奠定了坚实的实验基础、理论基础和技术基础。更多还原

【Abstract】 At present, seldom studies have been done on the detailed characteristics about essential parameters of the action course of blast wave, for the reason of its own complexity of explosion, the limitation of the test equipment and technology for testing the wave in adjacent area to a borehole in a concrete model, while destruction of the rock material results from the combination effect for the three kinds of blast stress acting. However, in recently, action course of blast wave still remains in determining the nature because it is difficult to do test to obtain signals of blast wave in adjacent area to a borehole, so studies are seldom done on the blast wave and rock damage evolution course with the separated stress. In order to solve the problems above, the author has done the systematical studies on the detailed characteristics of blast wave and rock damage evolution under blast wave in adjacent area to borehole combining with the two projects: the outstanding young teacher’s support plan—Study on the technique of the efficient rock breakage by blasting in deep mining and prevention against relevant catastrophe （EYTP-2134）, granted by Ministry of Education, and doctors fund subsidy subject of Ministry of Education "Recognition of blast wave signals and the dynamics process on it in adjacent area to a borehole". The main study results are as follows:Firstly, blast wave were tested successfully with characteristic of stabilizing, repeating, and high-efficiently in an all-round way for concrete through match studies on the dynamical measurement system and improving experimental technique for the first time. Comparing with other piezoelectricity or the pressure sensor, the systematic and experimental technique can exhibits the compressive and tensile stress, with non defect for the obtained data while the wave form is intact. The data reflected complicated action course of the blast wave truly. The experiment system and technique establish the solid experiment foundation for further quantitatively mechanism study and theoretical study for the rock blasting under blast wave in adjacent area to a borehole.Secondly, blast waves are recognized and divided into three sub areas, named first zone, second zone and third zone of stress wave action, based on analyzing the blast wave signals that had been tested in concrete and the theories of rock broken mechanism, etc. A rock broken course related to the each zone has been proposed for the first time. The damage process of the concrete is very complicated, in which occurs compressive, tensile by frist zone and second zone under the high strain rate with 10⁴/s as well as the quasi-static effect by third zone. On the space, the three kinds of blast wave act on the effective sphere of concrete at the same time. On time, they act on the measuring point sequentially and are the separate course, but. exist in inner link to the damage of the concrete.Thirdly, based on the reorganization for the blast wave under the condition of air decoupling charge, the detailed characteristics of the essential feature parameters in the separating area are obtained from different place in different coupling coefficient for the first time. Through analyzing essential features of the separating zones of blast wave, such as stress, loading strain rate and unloading rate, velocity and acceleration of particle,etc, the relationship among dynamics essential feature parameter of separating zones and the decoupling coefficient K and the distance from measuring point to bore hole is quantitatively established which have revealed deeply the detailed characteristics of propagating and mechanism of the instantaneous explosion wave in adjacent area to a borehole in a concrete model.Fourthly, combining with the others’ former achievement, while comparing the wave form of a back wave tested from free face and contact explosion experiment to the wave form in the bore hole, the dividing action zones and the tested data of separated area of blast wave are verified correctly. The producing mechanism of the separating zones of blast wave is set up interrelated with detonation structure of explosive and the theory of rock breaking. First zone of blast wave in concrete is the acting result of explosion pressure in the wave front of explosion detonation, and third zone is the acting result of the detonation product with isentropic amorphous expansion flow after C-J interface of explosion detonation. And second zone of balst wave in concrete produces complicatedly, and may relate to the damage of the rock.Fifthly, the technology of time-frequency energy is used to analyze the blast wave for the first time, in which the signal of the separating blast wave zones has the characteristics of short time, frequency band complicatedness, the maldistribution of energy density and fast sudden change. From adaptability that the technology of linear and non-linear time frequency distribution analyze non-steady random limited signal of energy in short-term, optimum function of time-frequency distribution is selected to analyze dynamical strain of blast wave by the contrast of many kinds of analytical methods of time-frequency distribution appraising and calculating to the blast wave signal. And it establishes solid theory and application foundation for using time-frequency distribution to analyze instantaneous blast wave.Sixthly, based on the selected optimum function, Rihaczek distribution is used to analyze the blast waves tested near the cavity of concrete under the condition of radial air decoupling charge. Blast wave is recognized accurately at three-dimensional space of time-frequency energy, and is separated to dynamical strain energy density zones by Rihaczek distribution. Then the time-frequency energy distribute characteristic of every zone, dynamic strain energy of every zone and total energy are calculated. The dynamic change relation relationship between total energy or dynamic strain energy of every zone with decoupling coefficient K and the distance R from measuring point to bore hole are established. They deeply reveal the energy mechanism of the separating zones and detailed characteristic of the energy centre evolving on instantaneous explosion waves.Finally, acoustic wave measurement technology is used to study the concrete damage after exploded and the damage evolving mechanism of structure which interrelated with the essential feature parameters and energy in the separating area is set up. Dynamic strain energy threshold E_cri related to damaging threshold value D_cri is put forward as energy criterion of rock damage. By comparing with E_cri and the dynamical strain energy of separating zones, it can be judged whether new cracks are produced. The function of first zone of blast wave action reflects in producing new cracks and expanding the cracks mainly. The function of second zone and third zone action is to expand the new cracks, and stress and energy centralized in damaging boundary.The above main conclusions obtained in the project have significant value both in theoretical investigation and engineering application with discipline of blasting engineering, defense engineering, constitutive relation of rock body, the characteristic of the seismic wave etc., and build a solid experiment foundation, a theoretical and technological basis for studying action characteristics of instantaneous blast wave and damage evolution of rock related blast wave in adjacent area to a borehole in concrete models更多还原