The CT Experiment Research On Fracture Distribution Of Coal Under Axial Loading And Unloading

In china the most of the rich coal basin have been experienced tectonic superimposition and reformation of multi-cycle times. The tectonic stress promotes the evolving of coal cracks and pores. This area often accompanied by the occurrence of coal and gas outburst accident. Just the structures lead the security problemes. In order to reveal the process of the coal fracture revolution law under axial loading and unloading. The article using the theory and practice to research on the evolution of the coal fractures under the axial loading and unloading by using the industry CT. The article research is on the development of the situation in the coal fractures under the different uniaxial pressure and using the Matlab to process the CT image date including histogram equalization and edge detection and binary image processing and image threshold. Processing the images we can found that the pressure more highly the white area in binary image will larger and the image density will increase significantly. We found the fissure pictures of fractal dimension are more closely and the fractures will more complex under the uniaxial pressure when calculating the coal fracture fractal features. The article simulates the situation of the changes in coal fractures under the different pressure and found that the more complex the greater the pressure crackly. It also found that the large longitudinal cracks began to appear when the pressure increasingly and the fracture will chiasm formation and crossing the fracture surface.