Correlation Between and Mechanisms of Gas Desorption and Infrasound Signals

Abstract

Coal and gas desorption, as a major form of gas energy release, is a key factor in triggering coal and gas outbursts. Therefore, studying the physical characteristics during coal and gas desorption is essential for understanding the development process of coal and gas outbursts. Based on gas dynamics during coal particle gas desorption, this study established a connection between gas desorption and infrasound signals, elaborating on the generation mechanism of infrasound signals during coal particle gas desorption and validating the feasibility of the theory through experimental data, thereby demonstrating the spontaneous occurrence of subsonic tremors during coal particle gas desorption. Combining observational data, it was found that the peak value of infrasound signals generated during desorption experiments is correlated positively with the initial pressure; while, the dominant frequency of infrasound signals is influenced by the proportion of intergranular pores and fractures within the experimental vessel. To further validate the theory of subsonic generation, a mathematical model describing pressure oscillations within intergranular pores, thereby explaining the mechanism of subsonic tremors, was established. The model confirms that the generation and characteristics of infrasound signals are controlled by the parameters of intergranular pores in coal samples. The model effectively simulates changes in the characteristics of infrasound signal tremors during desorption under different conditions, confirming that the physical properties of intergranular pores are crucial factors influencing the generation of infrasound signals and their characteristics during coal and gas desorption.