| This thesis aims to solve the problem that nearly all previous researches on coal and rock infrared characteristics are lacking of single variable analysis and quantitative description which is wide suitability. To reach this goal, the flattened Brazilian disk is introduced to investigate the infrared characteristics of a single fracture during startingcrack point and the propagation period. The simple relation between the real temperature increasement and critical stress intensity factor has been built, with which the estimation model of starting-crack point has been established based on the linear relationship between the real temperature and the infrared temperature. In addition, the infrared characteristics of fracture propagation period has been analyzed by using a new method which features for dividing four to five monitoring regions. Resuluts show that despite the real temperature experienced an increase during the whole farcureing process, the infrared temperature only showed an increase at starting-crack point rather than the propagation period. This also implies that the infrared characteristics related not only to the pressure but also be influenced by development speed, fracuture mode and the interaction of fratures. The research can help those who want to build a comprehensive judgment model of rock failure find a better way to analyze some key mechanical parameters related to infrared characteristics, and it also provides new methods and ideas about some physical modeling and engineering project on infrared characteristics. |
