## 3 Analysis of Test Data  
### Analysis of Surface Deformation Results  
Figure 9 shows that the surface settlement above the center line of the tunnel is more pronounced compared to the left line. For lateral monitoring points, the final settlement value at monitoring point 1 is 0.238 mm, which is 10.70% larger than the final settlement value of 0.215 mm at monitoring point 4. The settlement at monitoring point 2 is 12.03% larger than that at monitoring point 5, and the settlement at monitoring point 3 is 26.09% larger than that at monitoring point 6. This discrepancy arises from the multiple construction disturbances of the left and right guide holes and the middle guide hole affecting the surface above the center line, resulting in greater settlement. In contrast, the left line experiences a relatively smaller impact from the excavation of the left and middle guide holes, with the excavation of the right guide hole having less influence. Examining longitudinal monitoring points, the settlement at monitoring point 1 surpasses that at monitoring point 2 by 34.46%, monitoring point 2 exceeds monitoring point 3 by 205.17%, monitoring point 4 surpasses monitoring point 5 by 36.06%, and monitoring point 5 exceeds monitoring point 6 by 243.48%. This pattern indicates that the closer the location to the opening, the larger the surface settlement, while locations further from the opening exhibit smaller settlement values. The disturbance caused by the excavation of the first guide hole affects the surface of the cave entrance, and subsequent guide hole excavations continue to impact the surface, resulting in larger settlement values closer to the entrance. In this test, monitoring points 5 and 6, located at the surface of the unexavated soil behind the tunnel, experienced minimal settlement. While the excavation of the upper guideway exerts a more pronounced impact on surface settlement, the timely application of the upper guideway to the support structure following the completion of excavation serves to support and restrict the vertical displacement of the soil body. Consequently, the excavation of the lower guideway has a comparatively smaller impact on surface settlement. Focusing on monitoring point 1 for analysis, the surface settlement pattern of the tunnel reveals that the excavation of the upper guide hole directly beneath monitoring point 1 exerts the most significant influence on its settlement. Monitoring point 1 settles by 0.034 mm, 0.034 mm, and 0.052 mm after the excavation of the upper-left 1, upper-right 1, and upper-right 1 guide holes, respectively, accounting for 14.29%, 14.29%, and 21.85% of the total settlement value. The excavation of the upper guideway represents a crucial construction phase necessitating prompt application of support structures and vigilant monitoring. Subsequent excavation of the lower guideway has a diminished impact due to the support and restraint provided by the upper superstructure. The settlement from the excavation of the second and third ring sections amounts to 0.060 mm and 0.008 mm, respectively, constituting 25.21% and 3.36% of the total settlement value. Figure 9: Surface deformation time history curve of the first group. The general trend of surface settlement at monitoring point 1 indicates that in the early stage when the excavation surface is directly below the monitoring point, settlement drops rapidly with the largest settlement rate. As the excavation surface advances and gradually moves away from the monitoring point, the settlement rate diminishes, and the settlement curve gradually flattens out, ultimately stabilizing. Specific surface deformation data for the second group of tests are depicted in Figure 10. The surface settlement trend caused by different construction sequences exhibits slight variations, yet the overall pattern remains consistent. Settlement is primarily influenced by the excavation of the upper guide hole and the distance between the excavation surface.