## 4 Numerical Simulation Analysis of Roadway Layered Surrounding Rock Deformation
### Analysis of Simulation Results  
After the model ran, the distribution of the plastic zone of the roadway surrounding rock was obtained, as shown in Figure 9. The results show that the existence of the joint plane had a significant impact on the development of the plastic zone:  
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2. Without the influence of the joint surface, the development depth of the plastic zone of the roadway roof and the two sides was the same, the development depth of the plastic zone of the roadway floor was larger, and the plastic zone was less developed at the intersection of the two sides and the floor of the roadway. 3. When there was a joint surface, the shape of the plastic zone changed, and the depth of the plastic zone increased to a certain extent at the junction of the high top and the roof and the junction of the low-cut zone and the roof, as shown in Figure 9a zone 1 and zone 2. There was no plastic zone at the junction of the high top and the bottom plate, Figure 9a zone 3. In the roadway floor, the deepest zone of the plastic zone moved to the lower side of the roadway, Figure 9a zone 4. Under the influence of joints, in the junction of the lower side and the floor of the roadway, there was still a blind area for the development of the plastic zone, as shown in Figure 9a zone 5. According to the displacement monitoring results inside the surrounding rock during similar simulations, the displacement comparison diagrams of the monitoring points at the same position from the roadway surface in the four monitoring areas were drawn, as shown in Figure 10. The figure shows that the displacement of the right upper monitoring point was the largest, followed by the displacement of the left lower monitoring point, and the displacement of the left upper monitoring point was slightly larger than that of the right lower monitoring point. Comparing Figure 9, it could be found that the right upper and left lower monitoring points were located in the tangent zone between the rock formation and the roadway boundary (zone 2 and zone 3). The depth of the plastic zone in the area where the right upper point was located was larger than that in the area where the left lower point was located. At the same time, the roadway surface in the right upper area was parallel to the rock formation, while the roadway surface in the left lower area intersected at right angles. The left upper zone was located in the tangential vertical area between the rock formation and the roadway, and the right lower zone was in zone 5 at the junction of the low side and the floor. Figure 9: Comparison chart of plastic zone distribution. Further analysis of the stress monitoring point layout and stress monitoring results during a similar simulation and the distribution of the plastic zone in numerical simulation experiments' results are in Figure 11. The roadway adopted the straight wall and arc top, so it could be considered that the roadway was a circular excavation, and then the bottom plate was excavated at a right angle. To mark the distance of the monitoring point from the roadway surface, position reference lines 1 and 2 were drawn. Figure 11 shows the relationship between the position of the monitoring point and the plastic zone and the resulting difference in the stress monitoring data. The data of sensors No. 866 and No. 842 in the monitoring point fluctuated greatly, indicating that these two sensors were invalid. No. 816 was the farthest from the roadway surface, so the measured data was the largest; No. 1 and No. 2 sensors were close to the roadway surface, but the measurement directions of No. 1 and No. 2 were different, which led to different stress values measured by the two sensors. No. 1 was parallel to the tangential direction of the roadway, and the measured stress value was large, and No. 2 was perpendicular to the tangential direction of the roadway and the boundary of the plastic zone, and the stress value first increased and then decreased.