Analysis of damage characteristics and influencing factors of coal cut by cutting tooth based on industrial CT technology

In order to improve the dust production mechanism of intercepting tooth breaking coal, and to explore the dust production mechanism of intercepting and cutting. Based on the theories of elasticity, plasticity, rock mechanics, and cavity expansion, and from the perspective of coal damage, the equation for controlling the damage zone caused by the intrusion of cutting tooth into coal was established by analyzing the mechanical response characteristics after the intrusion of the cutting tooth into the coal. The sensitivity analysis method was adopted to determine the three main controlling factors affecting coal damage during cutting and breaking coal process: uniaxial compressive strength, confining pressure, and conical angle of cutting tooth. And based on industrial CT scanning technology, the experimental research on the cutting tooth intrusion into the coal under the condition of different main control factors has been carried out by utilizing the cutting tooth intrusion experimental device designed and processed independently. By binarizing and analyzing the CT digital images of the coal samples before and after the tooth intrusion, the quantitative analysis of the damage zone of the coal was realized. The experimental results indicate: As the uniaxial compressive strength of the coal samples, the confining pressure, and the angle of the truncated conical angle increase, the damaged zone caused by the penetration of the tooth into the coal is reduced. And the reduction in truncation conical angle was the greatest, confining pressure was the next greatest, and uniaxial compressive strength was the least.