水作用下不同粒径类岩试样力学性质及破坏特征研究
发布时间：2018-07-25 07:40
【摘要】：水岩作用一直是目前岩石力学研究的热点和难点之一。砂岩作为煤炭开采过程中一种常见的岩石类型,其力学性质涉及到煤炭开采过程的各个方面。此外,水-岩作用下,岩体各方面性质也受到不同程度的影响。目前,国内外的研究主要集中于某类岩石的干燥、自然、饱和三种特殊状态,且只考虑了水对某种特定岩石性质的影响,而忽略了岩石本身的性质。本文研究了水作用下不同粒径类岩试样力学性质和破坏形态,以期揭示水作用下岩石强度及变形特征随其粒径的变化规律。本文以水作用下不同粒径类岩试样为主要研究对象,综合运用室内试验及数值计算等方法,对不同粒径类岩试样在不同含水率状态下的力学性质及破坏形态进行了较为系统的研究。通过类岩试样吸水性试验、不同状态试样单轴压缩试验,掌握了不同粒径试样含水率随浸水时间的关系以及类岩试样单轴抗压强度、弹性模量、峰值应变随含水率及粒径的变化规律:不同粒径试样含水率与浸水时间变化可大致分为含水率匀速增长、含水率增速减慢、含水率趋零三个阶段;类岩试样单轴抗压强度和弹性模量与含水率呈负线性关系,峰值应变随含水率呈正线性变化;类岩试样单轴抗压强度、弹性模量和峰值应变与粒径分别呈反比例、正线性和负线性关系;并分别进行了敏感性分析。通过对水作用下不同粒径类岩试样声发射试验,从声发射计数的角度研究了不同含水率和粒径条件下,试样在各加载阶段的声发射特征,分析了粒径和水对声发射计数的影响;最后根据试验所得不同状态试样应力应变曲线,利用PFC2D进行了校核,采用校核参数模拟了试样单轴压缩试验和声发射试验,分析了水及粒径对试样内裂隙发育和破坏形态的影响,并研究了不同状态下,试样的声发射特性,发现含水率的上升,试样的声发射事件总数总体呈下降趋势;而粒径越大的试样单轴压缩过程中释放的声发射信号反而更多。
[Abstract]:Water-rock interaction has always been one of the hotspots and difficulties in rock mechanics research. Sandstone is a common rock type in coal mining, and its mechanical properties are related to all aspects of coal mining. In addition, under the action of water-rock, all aspects of the rock mass are also affected to varying degrees. At present, the research at home and abroad mainly focuses on the drying, nature and saturation of a certain kind of rock, and only considers the influence of water on certain rock properties, but neglects the nature of rock itself. In this paper, the mechanical properties and failure morphology of rock samples with different particle sizes under the action of water are studied in order to reveal the variation of rock strength and deformation characteristics with their particle size under the action of water. In this paper, the samples with different sizes of rock under the action of water are taken as the main research object, and the indoor test and numerical calculation methods are used synthetically. The mechanical properties and failure morphology of rock samples with different particle sizes under different water content were studied systematically. Through the water absorption test of rock-like samples and uniaxial compression tests of samples in different states, the relationship between moisture content of samples with different particle size and immersion time, uniaxial compressive strength and elastic modulus of rock-like samples were obtained. The variation of peak strain with water content and particle size: the variation of water content and soaking time of different particle size samples can be roughly divided into three stages: water content increases uniformly, water content increases slowly, water content tends to zero; The uniaxial compressive strength and elastic modulus of rock-like samples showed a negative linear relationship with moisture content, and the peak strain changed positively linearly with water content, while the uniaxial compressive strength, elastic modulus and peak strain of rock-like samples were inversely proportional to the particle size. The positive linear and negative linear relationships were analyzed respectively. Based on the acoustic emission test of rock samples with different particle sizes under the action of water, the acoustic emission characteristics of different water content and particle size were studied from the point of view of acoustic emission counting, and the effects of particle size and water on acoustic emission counting were analyzed. Finally, according to the stress-strain curves of samples in different states, PFC2D was used to check the test results. The uniaxial compression test and acoustic emission test were simulated by checking parameters. The effects of water and particle size on the fracture development and fracture morphology in the samples were analyzed. The acoustic emission characteristics of the samples under different conditions were studied. It was found that the total number of AE events decreased with the increase of water content. However, the larger the particle size is, the more acoustic emission signals are released during uniaxial compression.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD315
[Abstract]:Water-rock interaction has always been one of the hotspots and difficulties in rock mechanics research. Sandstone is a common rock type in coal mining, and its mechanical properties are related to all aspects of coal mining. In addition, under the action of water-rock, all aspects of the rock mass are also affected to varying degrees. At present, the research at home and abroad mainly focuses on the drying, nature and saturation of a certain kind of rock, and only considers the influence of water on certain rock properties, but neglects the nature of rock itself. In this paper, the mechanical properties and failure morphology of rock samples with different particle sizes under the action of water are studied in order to reveal the variation of rock strength and deformation characteristics with their particle size under the action of water. In this paper, the samples with different sizes of rock under the action of water are taken as the main research object, and the indoor test and numerical calculation methods are used synthetically. The mechanical properties and failure morphology of rock samples with different particle sizes under different water content were studied systematically. Through the water absorption test of rock-like samples and uniaxial compression tests of samples in different states, the relationship between moisture content of samples with different particle size and immersion time, uniaxial compressive strength and elastic modulus of rock-like samples were obtained. The variation of peak strain with water content and particle size: the variation of water content and soaking time of different particle size samples can be roughly divided into three stages: water content increases uniformly, water content increases slowly, water content tends to zero; The uniaxial compressive strength and elastic modulus of rock-like samples showed a negative linear relationship with moisture content, and the peak strain changed positively linearly with water content, while the uniaxial compressive strength, elastic modulus and peak strain of rock-like samples were inversely proportional to the particle size. The positive linear and negative linear relationships were analyzed respectively. Based on the acoustic emission test of rock samples with different particle sizes under the action of water, the acoustic emission characteristics of different water content and particle size were studied from the point of view of acoustic emission counting, and the effects of particle size and water on acoustic emission counting were analyzed. Finally, according to the stress-strain curves of samples in different states, PFC2D was used to check the test results. The uniaxial compression test and acoustic emission test were simulated by checking parameters. The effects of water and particle size on the fracture development and fracture morphology in the samples were analyzed. The acoustic emission characteristics of the samples under different conditions were studied. It was found that the total number of AE events decreased with the increase of water content. However, the larger the particle size is, the more acoustic emission signals are released during uniaxial compression.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD315
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