节理岩体的爆破颗粒流离散元模拟研究

发布时间：2018-03-27 12:05

本文选题：节理岩体　切入点：爆破　出处：《北京工业大学》2013年硕士论文

【摘要】：爆破作用过程中会产生巨大能量，因其具有一般机械或者人力所无法替代的优势而成为为工程建设服务的一种重要技术手段。在我国从20世纪50年代起爆破就已成为水电、煤炭、冶金、铁路交通和基础设施建设等工业领域中破碎岩体的主要方法。在实际工程中绝大多数的表层岩石被裂隙、溶洞等软弱结构面分割成节理岩体，节理破坏了岩石的整体性，使其强度降低；节理的存在为爆破能量的过早外逸提供通道，使爆破能量分布不均，从而影响爆破破坏形式。因此，研究节理岩体的爆破破坏机理，分析不同形式的节理对于岩石爆破能量分布及传播的影响，对于选取合理的爆破位置、提高爆炸能量利用率、改善爆破效果，保证施工安全等均有实际意义和重要的理论价值。本文基于以上问题，依托国家自然科学基金(40972189、51038009)和北京市自然科学基金（8111001），以河北赤城县某爆破开挖工程为背景，收集现场岩石参数、典型节理参数及爆破参数等资料，运用LS-DYNA与颗粒流离散元程序PFC相结合的方法，建立节理岩体爆破模型，研究总结不同形式节理对岩体中爆破能量传播及爆破漏斗成型效果的影响。论文的主要研究内容包括以下几点： 1.介绍颗粒流离散元程序，通过双轴加载试验总结分析细观参数（接触模型、摩擦系数、粘结强度等）对宏观力学性质的影响规律，为细观参数的选取提供理论依据；运用LS-DYNA软件模拟岩石爆破过程，，并选取距药包足够近的单元记录其速度时程曲线，然后将数据转换成PFC可读的文件格式，以便在PFC中实现炸药爆破的模拟； 2.结合实际工程岩体参数，并以室内试验曲线为标准，通过不断试算的方法拟合该曲线得到岩体颗粒细观参数，建立节理岩体模型。通过算例分析爆破能量在节理中的传播衰减规律验证模型参数、边界条件、阻尼等设定的有效性； 3.建立不同倾角节理的岩体模型，通过对节理两侧颗粒入射波和反射波速度峰值变化的分析，得出节理与药包连线夹角为90o时，节理对爆破能量的衰减作用最小； 4.通过对模型中两平行节理间距的改变，总结节理间距比率（节理间距与爆破波波长比值）对爆破能量传播的影响规律，结果显示节理对能量衰减的最大值发生在间距比率δ为1.2的情况中； 5.考虑节理与药包相对位置的多样性，建立节理与药包最小抵抗线及其延长线相交、垂直、平行的岩体模型，分析不同工况下爆破漏斗的成型效果。最后，就存在的问题和需要进一步研究的工作进行了简要的讨论。
[Abstract]:Blasting can produce huge energy in the process of blasting, because of its irreplaceable advantage of general machinery or manpower, it has become an important technical means to serve engineering construction. In our country, blasting has become hydropower since 1950s. The main method for breaking rock mass in industrial fields such as coal, metallurgy, railway transportation and infrastructure construction. In practical engineering, most of the surface rock is divided into jointed rock masses by cracks, weak structural planes such as karst caves, etc. The joint destroys the integrity of rock and reduces its strength, and the existence of joint provides a channel for premature escape of blasting energy, which causes the uneven distribution of blasting energy and affects the failure form of blasting. Therefore, the mechanism of blasting failure of jointed rock mass is studied. It is of practical significance and important theoretical value to analyze the influence of different joints on the energy distribution and propagation of rock blasting, to select a reasonable blasting location, to improve the utilization ratio of explosion energy, to improve the blasting effect and to ensure the safety of construction. Based on the above problems, this paper, relying on the National Natural Science Foundation of China 40972189 (51038009) and the Beijing Natural Science Foundation (8111001), and taking a blasting excavation project in Chicheng County, Hebei Province, as the background, collects the field rock parameters, typical joint parameters and blasting parameters, etc. In this paper, a jointed rock mass blasting model is established by combining LS-DYNA with particle flow discrete element program PFC. The effects of different joints on blasting energy propagation and blasting funnel forming effect in rock mass are summarized. The main contents of this paper are as follows:. 1. The discrete element program of particle flow is introduced. The influence of mesoscopic parameters (contact model, friction coefficient, bond strength, etc.) on macroscopic mechanical properties is summarized and analyzed by biaxial loading test, which provides a theoretical basis for the selection of meso-parameters; The rock blasting process is simulated by LS-DYNA software, and the velocity time history curve is recorded by selecting the unit close enough to the charge packet, and then the data are converted into the PFC readable file format, so that the explosive blasting simulation can be realized in PFC. 2. Combining with the actual engineering rock mass parameters and taking the indoor test curve as the standard, the mesoscopic parameters of rock mass particles are obtained by fitting the curve with the method of continuous trial calculation. By analyzing the propagation and attenuation law of blasting energy in joints, the validity of model parameters, boundary conditions and damping is verified. 3. The rock mass models with different dip joints are established. Through the analysis of the peak velocity variation of the incident and reflected waves of particles on both sides of the joints, it is concluded that when the angle between joint and charge line is 90 o, the effect of joint attenuation on blasting energy is the least. 4. By changing the distance between two parallel joints in the model, the influence of joint spacing ratio (ratio of joint spacing to blasting wave length) on blasting energy propagation is summarized. The results show that the maximum value of joint to energy attenuation occurs when the spacing ratio 未 is 1.2. 5. Considering the diversity of the relative positions of joints and charge packs, a rock mass model, which intersects, perpendicular and parallels the minimum resistance line and its extension line, is established, and the forming effect of the blasting funnel under different working conditions is analyzed. Finally, the existing problems and further research work are briefly discussed.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU45

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