单轴压缩条件下煤体裂隙细观CT探测实验研究

发布时间：2018-08-06 10:23

【摘要】：采动应力变化直接影响着煤岩裂隙发育程度,研究煤岩裂隙演化规律具有十分重要的意义。为了提高矿井的安全高效开采,本文基于损伤力学理论,运用实验和数值模拟相结合的方法,对受载条件下的煤岩体裂隙损伤与发育演化规律开展了研究。首先建立了损伤力学模型,然后在单轴压缩条件下完成了CT扫描实验,在此基础上,运用MATLAB软件提取图像信息,对裂隙的发育演化规律进行了研究。主要取得可以下研究成果:首先研究损伤力学理论,通过后续的试验与数据处理,拟合损伤理论模型。结果表明该模型能够较好的与实验测定曲线吻合,证明了模型的可行性和合理性。其次通过煤样的抗压实验,研究单轴压缩的各个过程,结合CT扫描图像,提取单轴压缩过程中四个阶段对应的CT图像。研究结果表明:裂隙的发育的原因主要是尖端附近的应力集中;在抗压试验过程中,煤岩体裂隙发育的方向主要是沿着轴向应力的方向劈裂;裂隙的发育主要是微裂隙的首先破坏,微裂隙的应力集中促进大裂隙的发育。最后运用MATLAB软件进行图像处理,研究煤岩体裂隙的发育演化规律。利用软件中的程序,完成CT图像的分析。通过图像灰度化处理和直方图的变换,研究发现煤岩变形破坏是一个由变形、损伤的发生和演化,细观裂纹的出现,宏观裂隙的产生,再通过裂隙扩展到贯通性破坏的全过程。裂隙的产生是次生裂隙到宏观裂隙的发育。贯通性裂隙的形成,煤样累积损伤量达到弹性屈服极限时,次生裂隙得以贯通,形成了较大的裂隙。
[Abstract]:The variation of mining stress has a direct influence on the development of coal and rock fissures, so it is of great significance to study the evolution law of coal and rock fissures. In order to improve the safety and efficiency of mine mining, based on the theory of damage mechanics and the method of combining experiment and numerical simulation, the law of damage and development of fracture in coal and rock mass under loading condition is studied in this paper. Firstly, the damage mechanics model was established, and then the CT scanning experiment was completed under uniaxial compression. On this basis, the rule of fracture development and evolution was studied by using MATLAB software to extract image information. The main research results are as follows: firstly, the damage mechanics theory is studied, and the damage theory model is fitted by subsequent experiments and data processing. The results show that the model is in good agreement with the experimental curve and proves the feasibility and rationality of the model. Secondly, each process of uniaxial compression is studied through the compression experiment of coal sample. Combined with CT scanning image, the corresponding CT images in four stages of uniaxial compression are extracted. The results show that the stress concentration near the tip is the main cause of fracture development, and the fracture direction of coal and rock mass is split along the direction of axial stress during compressive test. The development of fractures is mainly caused by the first failure of microcracks, and the stress concentration of microfractures promotes the development of large fissures. Finally, the development and evolution of coal and rock mass fissures are studied by using MATLAB software for image processing. Using the program in the software, the analysis of CT images is completed. Through image grayscale processing and histogram transformation, it is found that the deformation and failure of coal and rock is a whole process of deformation, damage occurrence and evolution, the appearance of mesoscopic cracks, the emergence of macroscopic cracks, and then extends through the cracks to the whole process of transfixibility failure. The formation of cracks is the development of secondary fissures to macroscopic fissures. When the cumulative damage of coal samples reaches the elastic yield limit, the secondary fractures can be broken through and a large crack is formed.
【学位授予单位】：华北科技学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD315

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