岩石形破坏过程中的能量演化机制姓

发布时间：2019-06-20 08:41

【摘要】：冲击地压、岩爆等岩体工程灾害本质上是能量非线性演化至灾变的过程,从能量角度研究岩石的变形破坏规律,可以突破应力应变分析的传统模式局限,对于岩体力学行为的深入认识带来一种新的视角和分析方法。本文针对岩石变形破坏过程中的能量演化机制,从能量转化作用、能量演化及分配规律、能量演化的非线性特性、能量演化的细观特征等四个方面研究了岩石在受载过程中的能量行为,主要取得以下进展： (1)分析了岩石变形破坏过程中的能量转化作用。受载岩石能量转化大致分为能量输入、能量积聚、能量耗散、能量释放四个过程,输入的总能量部分转化为弹性能,部分转化为其他形式的能量耗散掉；分别建立了碎块数量与耗散能、碎块速率与弹性能的关系,发现能量耗散决定了岩石破碎块度,碎块形成后剩余的弹性能决定了岩石破碎剧烈程度；能量驱动岩石变形破坏主要有两种机制：能量耗散使岩石抵抗破坏的能力降低、能量积聚使驱动岩石破坏的能力增强。 (2)获得了岩石变形破坏过程中的能量演化及分配规律。提出了岩石储能极限、残余弹性能密度和最大耗散能密度概念。单轴压缩下弹性能随应力呈现慢-快-慢的增长模式,并于破坏时释放出来,储能极限约为0.21MJ/m3,耗散能起初增长较缓慢,临近破坏时大幅增加,增幅可达85%左右,整个加载过程中输入能量转化为弹性能的比例约从60%增加到82%,临近破坏阶段有小幅下降。研究了岩石能量演化及分配规律的加载速率效应、围压效应、岩性效应和水环境效应,并进一步得到不同开采条件下能量演化的差异,无煤柱开采的工作面前方煤岩体最大弹性能密度是放顶煤开采的1.5倍,是保护层开采的2.3倍,而峰后能量释放速率也由保护层开采、放顶煤开采、无煤柱开采依次增大。 (3)揭示了岩石能量演化的分叉和混沌特性。建立了岩石能量转化的自我抑制模型,得到并验证了岩石内部能量随应力变化的演化方程,所建模型适用于岩石变形破坏峰前阶段；能量演化具有分叉和混沌性质,当轴向应力达到约92%峰值应力时,系统进入倍周期分叉区,达到约97.5%峰值应力时,进入混沌状态；提出了能量迭代增长因子μ,其表征岩石受载过程中能量的迭代增长效应,根据能量迭代增长因子的非线性演化,可将岩石变形破坏过程分为4个阶段：0μ≤1、1μ≤3、3μ≤3.5699、3.5699μ≤4,分别表征了岩石中的能量衰减、能量积聚、能量耗散和能量释放主导阶段。 (4)探究了岩石能量演化的细观特征。沟通了岩石细观几何及强度特征——能量演化特征——细观破裂特征的内在联系：一方面,得到了岩石细观基元的平均强度、均质度和特征尺度以及裂纹分布特征对岩石能量演化特征的影响规律,并建立了细观特征与能量耗散的关系,表明基元均质度决定了能量耗散的模式,而临界能耗值和基元平均强度决定了能量耗散的量值；另一方面,探讨了岩石能量演化特征对其细观破裂模式的影响,建立了有效冲击能指数与破裂面分形维数的关系,表明存在分形维数阈值,当破裂面分形维数小于此阈值时,岩石有效冲击能指数与分形维数值呈正相关关系,反之,呈反相关关系,建立了有效冲击能指数与微破裂演化之间的关系,表明有效冲击能指数越大,岩石微破裂演化表现为“突变”的性质,有效冲击能指数越小,岩石微破裂演化表现为“渐变”的性质。该论文有图138幅,表28个,参考文献245篇。
[Abstract]:The rock burst, rock burst and other rock mass engineering disasters are the process of the non-linear evolution of energy to the cataclysm, the deformation and failure of the rock is studied from the energy angle, the traditional mode limitation of the stress-strain analysis can be broken through, In this paper, a new perspective and analysis method is presented for the in-depth understanding of the mechanical behavior of the rock mass. In the light of the energy evolution mechanism in the process of rock deformation, the energy behavior of the rock in the loading process is studied from four aspects of energy conversion, energy evolution and distribution, nonlinear characteristics of energy evolution, and micro-characteristics of energy evolution. (1) The energy conversion in the process of rock deformation is analyzed. The energy conversion of the loaded rock is generally divided into four processes of energy input, energy accumulation, energy dissipation and energy release, and the total energy input is converted into elastic energy, and the energy is converted into other forms of energy to be dissipated; and the number and dissipation of the fragments are respectively established. The relationship between the energy dissipation and the energy dissipation determines the degree of rock fragmentation, and the energy-driven rock deformation is mainly composed of two mechanisms: energy dissipation reduces the capacity of the rock to resist the destruction. A low, energy build-up that increases the ability to drive the rock. The energy evolution and distribution in the process of rock deformation and destruction are obtained. Distribution law. The energy storage limit, the residual elastic energy density and the maximum dissipation energy density of the rock are put forward. Concept of degree. The elastic energy in single-axis compression presents a slow-fast-slow growth mode with the stress, and is released at the time of failure. The energy storage limit is about 0.21 MJ/ m3. The dissipation can initially increase relatively slowly. The increase of the increase can reach 85. On the left and right, the proportion of input energy into the elastic energy in the whole loading process is increased from 60% to 82%, and the adjacent failure phase is small The loading rate effect, the confining pressure effect, the lithology effect and the water environment effect of the rock energy evolution and the distribution law are studied, and the difference of the energy evolution under different mining conditions is further obtained. The maximum elastic energy density of the square coal rock mass before the work of the coal pillar mining is 1. And the release rate of the post-peak energy is also mined by the protective layer, the top coal mining and the non-coal pillar mining are carried out. (3) The bifurcation of the evolution of the rock's energy is revealed. The self-inhibition model of rock energy conversion is established, and the evolution equation of the internal energy of the rock changes with the stress is obtained. The model is suitable for the pre-peak phase of rock deformation failure. The energy evolution has the characteristics of bifurcation and mixing, and when the axial stress reaches about 92% When the peak stress is reached, the system enters the bifurcation area of the time period, reaches about 97.5% of the peak stress, and enters the mixed state; the energy iteration growth factor. mu. is put forward, which is characterized by the iterative growth effect of the energy in the loading process of the rock, and according to the energy iteration growth factor, The nonlinear evolution of rock deformation can be divided into four stages:0. mu.1,1. m.3,3. m., 3.5699, 3.5699. m.4, respectively. The energy attenuation, energy accumulation, energy dissipation and energy release in the rock are respectively characterized. In that lead stage. (4) the energy of the rock is explored. The micro-characteristics of the evolution are discussed. The internal relation of the micro-geometry of the rock and the characteristics of the strength and the characteristic of the energy evolution _ on the characteristics of the micro-fracture is communicated. On the one hand, the average strength, the homogeneity and the characteristic scale of the mesoscale of the rock and the characteristics of the crack distribution on the evolution of the rock energy are obtained. The influence law of the characteristics is established, and the relation between the micro-characteristics and the energy dissipation is established. The model of energy dissipation is determined by the average degree of the element, and the critical energy consumption value and the average intensity of the element determine the magnitude of the energy dissipation; on the other hand, the micro-structure of the rock energy evolution is discussed. The relationship between the effective impact energy index and the fractal dimension of the fracture surface is established, which indicates that the fractal dimension threshold exists. When the fractal dimension of the fracture surface is smaller than the threshold, the effective impact energy index of the rock is in a positive correlation with the fractal dimension value, and vice versa. The relationship between the effective impact energy index and the micro-fracture evolution is established, which shows that the larger the effective impact energy index, the evolution of the micro-fracture of the rock shows the nature of the "mutational", the smaller the effective impact energy index, and the rock micro-fracture evolution is

"Grady" . The paper is shown in Figure 138 with 28 tables
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU45

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