Study on the Coupling Characteristics of Infrasound-Temperature-Gas in the Process of Coal Spontaneous Combustion and a New Early Warning Method

The phenomenon of coal spontaneous combustion poses a serious threat to mine safety, and monitoring and warning of coal spontaneous combustion has become an important issue that needs to be urgently addressed in coal mines. The current monitoring and early warning methods for coal spontaneous combustion have their limitations, and a single indicator cannot accurately mark the degree of coal spontaneous combustion danger inside the goaf. Therefore, this article proposes a new method for monitoring coal spontaneous combustion through infrasound waves. Infrasound waves have advantages such as low attenuation and long transmission distance. However, current research on monitoring and warning coal spontaneous combustion in goaf through infrasound waves is not yet complete, and there is a lack of research on the characteristics of infrasound signal changes during coal spontaneous combustion. Based on this, the article first tested the characteristic temperature and release changes of indicator gases (CO, C2H4) through thermogravimetric experiments and coal oxidation and heating experiments. Then, the generation and variation of infrasonic signals during coal spontaneous combustion (CSC) was studied and analyzed using a self-designed CSC infrasonic testing system. The results showed that obvious infrasound signals could be generated during the CSC process, there is a good mapping relationship between signals and temperature. Furthermore, the analysis revealed the inherent relationship between the infrasonic signal, temperature, and indicator gas of coal at different oxidation stages. The research in this article has promoted the use of infrasound waves for temperature inversion and promoted the development of multi-parameter analysis and early warning of CSC, which is of great significance for the field of CSC monitoring.