【作者】 姜曦；

【导师】 李元辉；

【作者基本信息】 东北大学 ， 采矿工程， 2009， 硕士

【摘要】 岩石是自然界较典型的非均质材料,力学性质复杂多变,其变形破坏过程实际上是内部微裂纹的萌生、扩展、聚合(即内部损伤的逐步积累)直至最终形成宏观裂纹而失去承载能力的过程。分形几何是研究在自相似意义下事物所具有的尺度不变性的数学分支。实验证明,岩石的声发射序列不仅在空间上是分形分布的,而且在时间上也具有分形特征。本论文采用关联维数来描述岩石声发射时间序列的分形特征,研究岩石损伤破坏过程的演化规律。本文基于分形理论,利用matlab程序,通过对岩石声发射实验不同试样的时间序列进行计算分析,重点研究岩石不同破坏阶段分形关联维数的变化趋势,主要内容如下:(1)介绍分形理论及分维数的算法,应用关联维数的计算,对岩石加载过程中的声发射时间序列进行分析。(2)通过声发射实验,研究不同岩样(花岗岩、大理岩、砂岩、片麻岩)在单轴加载的方式下,声发射时间序列的分形特征。(3)通过分析关联维数与声发射事件率的关系,研究声发射关联维数值的变化与岩石破碎失稳过程之间的联系。(4)通过分析关联维数与最大破坏应力之间的关系,研究不同应力时关联维数的变化规律,在此基础上判断声发射时间序列关联维数对于预测预报冲击地压的参考价值。更多还原

【Abstract】 Rock is a typical non-isotropic material, the mechanical properties is complicated and diversified, its deformation failure process is the internal micro cracks generates, pores, joints (i.e. internal damage accumulate gradually) so that forms macroscopic crack to lose the bearing capacity. Fractal geometry is about things have scale invariance in self-similar meaning, it is the mathematical branch. The experiment showed rock acoustic emission sequence not only has fractal distribution in space, but also has fractal feature in times. Therefore, describe the fractal feature of acoustic emission time sequence by correlation dimension and research the evolution law of rock damage and failure process.Based on the fractal theory, using matlab program, calculate and analysis time sequence of different rock specimens acoustic emission, emphases on the trend of correlation dimension in various rock failure stages. There are following contents:(1)Introducing the fractal theory and the algorithms of fractal dimensions, analyzing the rock acoustic emission time sequence in rock loading process by calculating correlation dimension.(2)By acoustic emission experiment, studying the rock acoustic emission time sequence fractal features of different kinds of rock (granite, marble, sandstone and gneisses) in uniaxial loading.(3)By analyzing the relation to correlation dimension and acoustic emission rate, studying the relation to the change of acoustic emission correlation dimension and rock failure instability process.(4)By analyzing the relation to correlation dimension and maximum failure stress, studying the change regularity of correlation dimension ,which are under different stress in rock loading process. Based on above, estimating the reference value of rockburst predicating and forecasting which is about correlation dimension of rock acoustic emission time sequence.更多还原