## 4 Stress Distribution Law in Island Working Face
### Numerical Simulation Results Analysis  
#### 4.2.1 The Stress Distribution Influenced by Buried Depth  
Under different buried depth conditions, we simulated the stress distribution characteristics of the island working face, and the results are shown in Figure 12a. With the increase of the buried depth of the coal seam, the plastic zone range of the roadway surrounding the rock and coal pillar in the island working face shows a trend of gradual expansion, and the peak stress is also gradually increasing. It is worth noting that with the increase of buried depth, the position of the stress peak is also moving to the center of coal pillar and the deep part of the entity coal. Figure 12b shows the stress variation law of the coal pillar and the evolution characteristics of the plastic zone under different buried depths conditions. It is evident from the figure that when the buried depth is 300 m, 400 m, 500 m, and 600 m, the total proportion of the number of grids in the plastic zone proportion of the coal pillar is 41.67%, 56.25%, 69.17%, and 72.08%, respectively, and the corresponding peak stress of the coal pillar is 25.6 Mpa, 33.5 Mpa, 39.8 Mpa, and 40 Mpa, respectively. When the coal pillar width is 30 m, it still shows good bearing capacity. However, when the buried depth increases to 500 m and 600 m, the difference between the plastic zone and the peak stress of the coal pillar gradually decreases, and the change trend gradually becomes gentle. This phenomenon may imply that the coal pillar is close to its maximum bearing limit. Figure 12c shows the variation law of the peak stress of the entity coal under different buried depths. It is evident from the figure that with the increase of the buried depth, the peak stress of the island working face is 24.4 Mpa, 32.2 Mpa, 40 Mpa, and 47.3 Mpa, respectively, showing an obvious increasing trend. This change rule shows that there exists a direct correlation between the peak stress of the entity coal and the buried depth; that is, with the increase of the buried depth, the stress of the entity coal will increase accordingly. Therefore, compared with shallow coal seams, deep coal seams are more prone to disasters such as rock burst. This conclusion provides an important basis for us to deeply understand and evaluate the mining safety of deep coal seams. In practical engineering, we need to  
Figure 11: Simulation and calculation matching results.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Scheme**} & **Buried Depth** & **Gob Length** & **Working Face Length** & **Coal Seam Thickness** & **Coal Pillar Width** \\  & **H/m** & **L/m** & **D/m** & **M/m** & **B/m** \\ \hline
1 & 300/400/500/600 & 400 & 30 & 16 & 200 \\
2 & 200 & 100/150/200/250 & 30 & 16 & 200 \\
3 & 200 & 400 & 100/150/200/250 & 16 & 200 \\
4 & 200 & 400 & 30 & 8/12/16/20 & 200 \\
5 & 200 & 400 & 30 & 16 & 10/20/30/40 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Experimental scheme.  
fully consider the buried depth conditions, and take effective stress management measures and technical means to guarantee the safety and efficiency of deep coal seam mining.