Abstract:

 Coal is a special kind of rock that is sensitive to stress and strainUnder different stressstrain environment and tectonic stress effect, the physical structure, chemical structure, characteristic of optical property, etcof coal will greatly be changed, and tectonic coal with different structural characteristics and types will be formedVitrinite reflectance changes regularly during the process of tectonic coal deformation, which is extensively applied to the quantitative analysis of coalfield structureThis is also confirmed by deformation experiments under high temperature and confining pressureIn order to further investigate the microscopic mechanism of the change of vitrinite optical fabric, Xray diffraction, paramagnetic resonance and nuclear magnetic resonance were used to study the chemical structure of different types of tectonic coal and experimentally deformed coals under high temperature and confining pressureResearch shows that there is a close internal relation between the evolution of tectonic coal chemical structure and the vitrinite reflectanceThe optical property anomaly of vitrinite reflectance is a concrete manifestation of chemical structure evolution of tectonic coal in physical optical propertyDifferent physical and chemical structure in different types of tectonic coal resulted in a great difference in the characteristics such as gas content, permeability, etcMylonitic coal developed area is a dangerous belt for gas outburst in coal mine because of its high gas content and low permeability which are determined by special physical and chemical structuresTherefore, we can evaluate and predict the enrichment of mine gas and outburst hazard through studying distribution laws of tectonic coalIt provides a new thought and method for research on mine gas disaster.

Key words: tectonic coal; vitrinite reflectivity; chemical structure; characteristics of gas; coupling mechanism