## 4 Results and Discussion  
### Analysis of Excavation Sequence  
#### 4.1.1 Deformation Analysis  
(1) Deformation analysis of the surrounding rock and tunnel  
The deformation patterns of the surrounding rock under different excavation sequences were generally consistent. Taking the excavation sequence of \"1234\" for example, the vertical deformation cloud map and horizontal deformation cloud map are shown in Figures 5 and 6, respectively. From Figure 5, it could be observed that the vertical deformation of the surrounding rock was mainly concentrated at the arch top and the arch bottom, exhibiting a form of settlement and uplift. From Figure 6, it could be seen that the horizontal deformation of the surrounding rock was mainly concentrated at the junction between the tunnel and the middle partition wall, as  
After construction, the maximum deformation occurred in the more deeply buried double-arch tunnel. Among them, the maximum settlement deformation was observed at the left upper arch shoulder of Tunnel 4, marked as point A. The maximum uplift was observed at the right lower side of Tunnel 3, marked as point B. The maximum horizontal displacement was observed at the right upper arch shoulder of Tunnel 3, marked as point C. The locations of points A, B, and C are shown in Figure 7.  
The variation of the deformation indicators at points A, B, and C under different excavation sequences are shown in Figure 8a-c. Overall, the deformation process of the tunnel consisted of two stages: \"slow deformation\" and \"rapid deformation\". The \"slow deformation\" was the disturbance deformation caused by the excavation of surrounding tunnels, while the \"rapid deformation\" was the direct deformation caused by the excavation of the tunnel itself. According to Figure 8a,b, it could be observed that the final cumulative values of the settlement at the arch top and the uplift at the arch bottom remained around 21 mm and 13 mm, respectively, regardless of the excavation sequence. This indicated that the influence of the excavation sequence on the vertical deformation of the tunnel mainly lay in the difference in the occurrence times of the \"slow deformation\" and \"rapid deformation\", while the final cumulative values were relatively similar. According to Figure 8c, it could be seen that the final cumulative values of the horizontal deformation of the tunnel differed to some extent under different excavation sequences. The horizontal deformation under the \"1234\", \"2134\", \"3412\", and \"3421\" sequences was approximately 22 mm, while it was around 26 mm under the \"1243\", \"2143\", \"4312\", and \"4321\" sequences. This indicated that the final cumulative values of the settlement deformation caused by the excavation sequence are shown in Figure 8a-c.  
Figure 6: Horizontal displacement cloud map. Figure 7: Measurement points of Tunnel 4.  
that the excavation sequence also affected the final value of the horizontal deformation. To better control the horizontal deformation of the tunnel, it was recommended to adopt the \"1234\", \"2134\", \"3412\", and \"3421\" sequences. 2. Tipping analysis of the middle partition wall  
The tilting of the middle partition wall was mainly related to its horizontal displacement. Regardless of the excavation sequence, the middle partition walls on the left and right sides would experience tilting deformation, and the maximum deformation would occur at the top of the partition wall [16]. However, different excavation sequences had a certain influence on the tilting displacement of the middle partition wall. For example, when comparing the excavation sequences \"1234\" and \"1243\" as shown in Figure 9,b, it was observed that the maximum horizontal displacement of the middle partition wall 2 was smaller in the \"1234\" sequence compared to the \"1243\" sequence.