Research on quantitative characterization method of regional stress field in coal seams based on microseismic and computed tomography (MS-CT): A case study

Abstract The growing burial depth increases the potential risk of ground stress-induced coal and rock dynamic disasters in coal mining. This study attempts to use microseismic and computed tomography (MS-CT) to quantitatively characterize the stress field in coal seam areas. A comprehensive approach encompassing laboratory experiments, numerical simulations, and field investigations was employed to accomplish this objective. The experimental findings suggest a power function relationship between the wave velocity of coal and stress. The model relating wave velocity ratio to stress proves more suitable for research on stress field quantification. This model captures the positive correlation between wave velocity and stress changes and eliminates the influence of sample differences through normalization, rendering the fitting parameter b applicable in the field. This paper takes the No.22 coal seam of Jinjia coal mine as the research object; MS-CT technology was used to generate the cloud map of wave velocity field distribution in the 11224 working face and combined with the experimentally established relational model to relate the wave velocity ratio to the stress and calculate the results of quantitative characterization of the regional stress. At the same time, a detailed three-dimensional numerical model was established and simulated to obtain the stress distribution in the 11224 working face area. Comparison of the simulated stress field results with the quantitative results of MS-CT shows that the general trend is basically the same, and the stress is higher in the area with greater burial depth. The area affected by the overlying goaf has lower stress in the coal seam. The maximum error value of the two is within ± 2 MPa, and the correlation coefficient is 0.79, indicating a strong correlation. Therefore, the MS-CT technique combined with the experimental wave velocity-stress coupling relationship model can determine the stress field distribution and realize the quantitative stress characterization. This provides a crucial foundation for analyzing the mechanical model of coal seam instability and calculating the judgment index of coal-rock dynamic disaster excitation.