Distribution characteristics of the advance abutment pressure in a deep stope

The advance abutment pressure on the coal mining face of a deep stope plays a decisive role in the surrounding rock instability, rock burst and coal-gas outburst. Based on distributed optical fiber sensing technology and theoretical analysis of the stress state, the distribution characteristics of the advance abutment pressure were tested. Taking the 61103 coal mining face of a mine in Inner Mongolia as an example, downhole measurement research was carried out. Based on the monitoring data, a two-dimensional (2D) geological model for the distribution of the advance abutment pressure during the mining process was developed. To verify the validity of the model, a verification borehole was located on the 61201 coal mining face of the same mining area, the two borehole datasets were comprehensively analysed and the model was corrected. The modified model shows that the influence scope of the advance abutment pressure is 0-26.5 m, the position of the peak stress is 5.1-6.4 m in front of the coal mining face and the peak stress can reach 21.98-23.98 MPa. The stress concentration coefficient is 1.22-1.91 and the vertical influence depth is 13-14 m. Moreover, the advance abutment pressure exhibits obvious zoning in the transverse direction, and the stress at the same position in front of the coal mining face will undergo a process of steady-slow increase-significant increase-peak-decrease. The technical parameters obtained from this study can be used for other coal mining faces in the area. In addition, the testing result of the abutment pressure from the distributed optical fiber sensors is effective and can provide a new research method for mine safety monitoring.