基于微型试件的煤岩力学与渗流规律研究

发布时间：2018-03-10 04:35

本文选题：微型试件　切入点：煤岩试验机　出处：《太原理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着中国经济的崛起，各大工程项目正处在紧锣密鼓的建设当中，很多大的工程都涉及到了岩石力学和岩石渗流学的知识，在这些领域内的专业研究还不足以解决实际的一些工程问题，尤其在一些矿业工程当中，因此，研究煤岩材料的力学与渗流损伤规律，具有广泛的工程意义。数十年来，煤岩材料的力学和渗流学研究，主要针对的是一些大中型试件的变形损伤规律的研究，在小型，甚至在微型试件的研究领域，成果还很少，因此，本文针对微型煤岩试件的实验研究，能够一定程度上弥补这方面的空白。通过对材料特性的分析，选取了黄色粉砂岩和晋城15号无烟煤作为本文试验的主要试件材料，并钻取了直径为6mm,长度为12mm的试件。微型煤岩试验机能够针对微型试件进行单轴压缩、三轴压缩，配合本文设计的煤岩实验系统，进行了煤岩渗流方面的一系列研究。将煤岩试验机和CT系统配合使用，完成了对煤岩材料力学和破裂渗流学方面的的研究，得到了大量的可靠数据。本文主要采用实验和理论来分析微型试件的煤岩力学与渗流规律，在理论分析方面，分别从煤岩力学和渗流学两方面展开，，力学分析了煤岩变形破坏理论、煤岩力学实验发展和煤岩应力-应变曲线特点；渗流学分析了水-岩作用理论、煤岩渗流理论和煤岩在应力-渗流耦合作用下的渗流理论。单轴压缩实验证明了煤岩材料的强度与变形不仅与材料所含矿物颗粒有关，还受内部裂隙孔隙结构的形式、大小影响。砂岩试件的强度和变形还与试件的径长比和尺寸有关，而无烟煤试件的强度和变形具有显著的各向异性。三轴压缩实验表明，随着围压的增大，各类试件的强度和变形都逐渐变大。通过分析残余强度，指出黄砂岩属于偏脆性的岩石材料，而无烟煤属于偏塑性。单轴压缩软化实验表明，随着浸水时间（含水率）的增加，煤岩材料遇水软化，强度和变形发生了较大变化，无烟煤展现了浸水软化的各向异性。煤岩材料渗流实验指出，煤岩渗流性与内部裂隙结构息息相关，围压一定，随着渗透压增加，强度和变形逐渐减小。破裂煤岩渗流规律研究发现，围压和渗透压对煤岩材料的渗流性能都起着决定性的作用，渗透压一定，围压增加，单位时间流量成负指数递减，渗透系数和渗透率减小；围压一定，渗透压增加，情况相反，但由于水的吸附作用，渗透系数和渗透率先减小，后上升。通过CT分析了煤岩试件的破坏变形和渗流的影响因素，并发现破裂煤岩的逾渗概率与其所受的围压与渗透压有关。虽然实验设计和操作上还存在许多的不足之处，但通过本文的实验研究和理论分析，从一定程度上揭示了针对微型试件的煤岩力学与渗流损伤规律，具有重要的意义。该论文得到了国家自然科学基金项目（51104105）的支持。
[Abstract]:With the rise of China's economy, major engineering projects are in the midst of intensive construction. Many major projects involve knowledge of rock mechanics and rock seepage. The professional research in these fields is not enough to solve some practical engineering problems, especially in some mining projects. Therefore, it is of great engineering significance to study the mechanics and seepage damage law of coal and rock materials. The research on mechanics and percolation of coal and rock materials is mainly aimed at the study of deformation and damage law of some large and medium-sized specimens. In this paper, the experimental study of miniature coal and rock specimen can make up the gap to some extent. The yellow siltstone and Jincheng No. 15 anthracite are selected as the main materials in this paper. With the diameter of 6 mm and the length of 12 mm, the minitype coal and rock testing machine can carry out uniaxial compression and triaxial compression for the micro specimen, and cooperate with the coal and rock experimental system designed in this paper. A series of research on percolation of coal and rock has been carried out. With the help of coal and rock testing machine and CT system, the mechanics of coal and rock materials and fracture percolation have been studied, and a large number of reliable data have been obtained. In this paper, experiments and theories are used to analyze the mechanics and seepage law of coal and rock. In theory analysis, the deformation and failure theory of coal and rock are analyzed respectively from two aspects: coal and rock mechanics and percolation. The experimental development of coal and rock mechanics and the characteristics of stress-strain curve of coal and rock are analyzed. The theory of water-rock interaction, the theory of coal and rock seepage and the seepage theory of coal and rock under stress-seepage coupling are analyzed. Uniaxial compression tests show that the strength and deformation of coal and rock materials are not only related to the mineral particles contained in the material, but also affected by the form and size of the pore structure of internal fractures. The strength and deformation of sandstone specimens are also related to the diameter ratio and size of the specimens. However, the strength and deformation of anthracite specimens have remarkable anisotropy. Triaxial compression tests show that the strength and deformation of all kinds of specimens increase with the increase of confining pressure. It is pointed out that yellow sandstone belongs to brittle rock material and anthracite to partial plasticity. Uniaxial compression softening experiment shows that the strength and deformation of coal and rock materials change greatly with the increase of water immersion time (water content). Anthracite shows the anisotropy of soaking and softening. The percolation experiment of coal and rock material indicates that the percolation property of coal and rock is closely related to the internal fracture structure, and the confining pressure is constant, with the increase of osmotic pressure, The study of percolation law of fractured coal and rock shows that both confining pressure and osmotic pressure play a decisive role in the percolation performance of coal and rock materials. When the percolation pressure is constant, the confining pressure increases and the unit time flow decreases exponentially. The permeability coefficient and permeability decrease, the confining pressure is fixed, the osmotic pressure increases, the situation is opposite, but due to the adsorption of water, the permeability coefficient and permeability decrease first and then rise. It is also found that the percolation probability of fractured coal and rock is related to the confining pressure and osmotic pressure. Although there are still many deficiencies in the design and operation of the experiment, through the experimental research and theoretical analysis in this paper, to a certain extent, the law of coal rock mechanics and seepage damage is revealed. This paper is supported by the National Natural Science Foundation of China (51104105).
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD315

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