## 4 Analysis of the Similar Experiment Results
### Distribution Characteristics of Support Pressure  
The maximum stress at the first-layer stress measurement point occurred an average distance of 12.5 m from the working face, with an average stress of 7.68, an average stress concentration coefficient of 2.64, and an average range of influence of the support pressure of 32.5 m. The maximum stress at the second-layer stress measurement point occurred 8.75 m from the working face on average, with an average stress of 7.62, an average stress concentration coefficient of 2.74, and an average range of influence of the support pressure of 32.5 m. The maximum stress at the third stress measurement point occurred an average distance of 5 m from the working face, with an average stress of 7.71, an average stress concentration coefficient of 2.9, and an average range of influence of the support pressure of 35 m. According to the stress measurement point data, as the layer of the roof rock at the stress measurement point increased, the maximum support pressure approached the working face, and the stress magnitude, stress concentration coefficient, and influence range did not substantially change. The maximum stress at the third-layer stress measurement point was 8.75 m from the working face on average, with an average stress of 7.67, an average stress concentration coefficient of 2.76, and an average range of influence of the support pressure of 33.3 m.  
The overlying rock in the mining area experienced the influence of repeated mining on the previous adjacent working face and this working face before and after mining. After mining, the thick and hard rock layer in the goaf broke, and the adjacent fractured rock blocks formed a masonry rock beam structure under the interlocking effect. After the coal seam in the lower working face is mined out, an unloading space is formed in the overlying rock of the roof above the goaf. As the coal seam is gradually mined, when the unloading space range meets certain conditions, the overlying rock layer will collapse under the action of its own weight and overlying rock load [35; 36]. The overlying rock collapse pattern is a transitive development trend from the bottom to the top of the coal seam roof, with obvious layering and grading characteristics. The activity of the overlying strata in the goaf is the result of the interaction between the stress in the mining area and the strength of the overlying strata. When the roof overlying strata collapse to the position where the ultimate bearing rock layer is located, their collapse height no longer develops. In the overlying strata in the goaf, the structural effect of \"stress arch\" is formed due to the self-organizing limitation of the overlying strata failure and movement. At the same time, the interaction between the fractured blocks after the collapse of the overlying rock in the mining area forms the \"fractured arch\"; the \"fractured arch\" in the overlying rock structure of the mining site is located within the range of the \"stress arch\" pressure relief zone. The stress arch mainly bears and transmits the load of the overlying rock layer; the  
Figure 14: Variation in the convergence of the overlying strata with the advance of the working face.  
hinge structure formed by the fracture of the overlying rock in the \"fractured arch\" mining area is the main load factor for the manifestation of strong mining pressure.