## 4 Results
### Effect of Stress Disturbance
#### 4.1.2 Surrounding Rock Stress of Main Inclined Shaft after Excavation of Electromechanical Chamber  
Figures 11-14 show the plastic zone range, bolt structural unit, stress distribution in Z direction and Y direction of the four monitoring areas of the section taken by the model after the excavation of the electromechanical chamber in the main inclined shaft. For X (10, 12), the plastic zone range of roadway-surrounding rock is formed by the combined action of stable tensile stress, stable shear stress and unstable shear stress. The roadway floor and the central axis are only affected by stable tensile stress, and the floor near the two sides is formed by shear stress and tensile stress. The maximum stress of the anchor cable is \(7.5\times\) 10\({}^{6}\) Pa, the stress range of the anchor bolt is \(-\)5.7461 \(\times\) 10\({}^{6}\) Pa\(\sim\)2.6177 \(\times\) 10\({}^{7}\) Pa, and the maximum stress is the end of the bottom angle of the two sides. The vertical principal stress of the roadway floor is 8.7118 \(\times\) 10\({}^{4}\) Pa, and the maximum vertical principal stress of the roadway side is \(-\)2.2340 \(\times\) 10\({}^{7}\) Pa. The maximum shear stress on the roof of the roadway side is \(-\)2.4305 \(\times\) 10\({}^{7}\) Pa, and the shear stress on the surrounding rock of the roadway decreases from the roof along the two layers to the roadway side and the floor. The minimum shear stress is \(-\)9.4713 \(\times\) 10\({}^{5}\) Pa.  
Figure 11: Plastic zone range of the four monitoring areas after excavation of electromechanical chamber. Figure 12: Cable force of the four monitoring areas after excavation of electromechanical chamber. Figure 13: Z–direction stress distribution of the four monitoring areas after excavation of electromechanical chamber. For X (25, 27), the plastic zone of roadway-surrounding rock is mainly formed by stable shear stress, and there is a plastic zone formed by a small amount of unstable shear stress and stable shear stress in the floor. The maximum stress of the anchor cable is \(7.5\times 10^{6}\) Pa, the stress range of the anchor bolt is \(-5.7641\times 10^{5}\) Pa-\(2.6177\times 10^{7}\) Pa, and the maximum stress is the end of the bottom angle of the two sides. The vertical principal stress of the roadway floor is \(1.9796\times 10^{5}\) Pa, and the maximum vertical principal stress near the head chamber of the belt roadway is \(-4.1689\times 10^{7}\) Pa. The maximum shear stress of the roadway roof is \(-2.4516\times 10^{7}\) Pa, and the minimum shear stress is \(-7.8189\times 10^{5}\) Pa. The simulation calculation shows that the shear stress of the floor is much larger than that of the roadway roof. For X (50, 52), the plastic zone of the surrounding rock of the first side of the tunnel and the floor is greatly affected by the unstable shear stress, but the plastic zone of the surrounding rock is still formed by the stable shear stress in a large range. The maximum stress of the anchor cable is \(3.9828\times 10^{7}\) Pa, and the stress range of the anchor rod is \(5.0\times 10^{6}\) Pa-\(3.9828\times 10^{7}\) Pa. The maximum stress is the end of the anchor rod at the bottom corner of the two roadways. The vertical principal stress of the roadway floor is \(2.6884\times 10^{4}\) Pa, and the vertical stress range of the surrounding rock is \(-2.5\times 10^{6}\) Pa\(\ldots-3.8016\times 10^{7}\) Pa. The local stress concentration area appeared on the roadway roof, with the maximum shear stress of \(-2.9983\times 10^{7}\) Pa and the minimum shear stress of \(-2.0561\times 10^{5}\) Pa. Compared with the unexcavated electromechanical chamber, the shear stress increases with an increment of \(0.1619\times 10^{5}\) Pa.  
For X (67, 69), this interval is the main inclined shaft section near the electromechanical chamber. Due to the excavation of the electromechanical chamber, the surrounding rock of the main inclined shaft has a large area of plastic zone formed by unstable shear stress.