## 4 Numerical Simulation Analysis on Roof Blasting Pressure Relief
### Results and Analysis  
The values of stress and displacement were obtained by monitoring measurement points set up around the roadway. The vertical stress and displacement cloud maps calculation to equilibrium before and after blasting was applied is illustrated in Figure 5.  
From Figure 5a, the main roof's overhang remained relatively intact prior to the roof cutting, and there was a stress concentration area above the coal pillar diagonally. The vertical displacement deformation of the 21108 gob-side roadway after excavation and calculation to equilibrium is shown in Figure 5b. It illustrates that the displacement of the roof was larger above the coal pillar; the displacement of the main roof above the solid coal area was basically 0. The large deformation was produced on the coal pillar and irregular deformation was produced along the gob-side roadway, and furthermore, the displacement of the side of the coal pillar was obviously larger than the deformation of the solid coal side. Figure 5c shows delineated equilibrated vertical stress distribution post-blasting. It demonstrates that a stress concentration area was observed above the coal pillar, but was still less than the stress prior to blasting. Compared with Figure 5b, it is evident that the stress in the range of the main roof breakage blasting was reduced due to blasting, resulting in a reduction in the stress in the solid coal area. The coal pillar exhibited negligible stress redistribution due to persistent structural coupling between the fragmented roof margin and the pillar geometry. The vertical displacement increment following blasting is illustrated in Figure 5d. Comparing the vertical stress cloud map prior to roof cutting, the main roof of the broken blasting range due to parameter weakening and deformation increased, the coal pillar produced large deformation. Irregular deformation was observed along the gob-side  
Figure 5: Stress and displacement maps next to the 21108 gob-side roadway. (**a**) Vertical stress before blasting; (**b**) Vertical displacement before blasting; (**c**) Vertical stress after blasting; (**d**) Vertical displacement after blasting. roadway, with the coal pillar side experiencing noticeably greater deformation than the solid coal side. Figure 5 demonstrates that the blast-induced fracture zone laterally exceeded the coal pillar's dimensions. The pillar deformation was diminished and stress transfer mechanisms to adjacent coal seams were attenuated, thereby achieving a substantial mitigation of peak stress concentrations within the solid coal side. Figure 6 illustrates the vertical stress value at varying distances along the gob-side roadway both before and after blasting. It is evident that the peak stress in the coal seam decreased by 3.54 MPa, from 24.23 to 20.69 MPa, respectively, with the peak stress situation occurring at a depth of 9 m and 15 m, respectively, so the place where a peak stress occurs was transfered deeper into the rock body by 6 m. Hence, it can be seen that blasting can mitigate the likelihood of a rock burst by moving a stress concentration from the vicinity of a gob side roadway deep to the solid side of intact coal. Furthermore, a reduction of 3.54 MPa in stress significant under real mining conditions significantly lowers the peak static load stress in the coal body of an adjacent goat roadway and enhances the surrounding rock stress environment, thereby decreasing the likelihood of a rock burst. The recorded displacement data and trends are displayed in Figure 7. When blasting was not carried out, the cantilever rock block exerted a loading effect on the solid coal in the gob-side roadway. The roof, coal pillar and solid coal all have formed large deformation, and the maximum displacement was 9.5, 10.8 and 4 cm, respectively.