# Dynamic Response Analysis of Soil around Curve Section Tunnel under Train Vibration Load
## 5 Analysis of Computational Results
### Analysis of Vertical Deformation Response  
From Figure 18, it can be observed that under the influence of train vibration loads, areas with larger vertical displacements are mostly located near the tunnel, with smaller settlements as the distance from the tunnel increases. Among them, the maximum vertical displacement is the smallest at the top of the tunnel, measuring approximately 1.035 mm. The maximum vertical displacements on both sides of the tunnel are almost equal, measuring 1.038 mm and 1.039 mm, respectively. The maximum vertical displacement is the largest at the bottom of the tunnel, measuring approximately 1.054 mm.  
Selecting nodes located directly beneath the tunnel at distances of 0 m, 2 m, 5 m, 8 m, 15 m, and 25 m from the tunnel base, the vertical deformation responses after a single load are studied. The vertical deformation of the analysis points after a single load is shown in Figures 19 and 20. Under the influence of train vibration loads, areas with larger vertical displacements are mostly located near the tunnel, with smaller settlements as the distance from the tunnel increases. The locations with the maximum settlements are concentrated at the top and bottom of the tunnel. Among them, the smallest maximum vertical displacement is the smallest at the top of the tunnel, measuring approximately 1.035 mm. The maximum vertical displacement is the largest at the bottom of the tunnel, measuring approximately 1.054 mm.  
ment occurs at the top of the tunnel, and the maximum vertical displacements on both sides of the tunnel arch are almost equal. The largest maximum vertical displacement occurs at the bottom of the tunnel.  
The vertical deformation trends are similar in the vicinity of the tunnel and within the soil mass, while the vertical deformation trend at the ground surface is significantly different. This trend indicates that when the train vibration loads act on the tunnel, the vertical deformation around the tunnel undergoes much larger variations compared to the vertical deformation at the ground surface. At the same time, the maximum vertical displacements occurring around the tunnel are also much larger than those occurring at the ground surface. From Figures 19 and 20, it can be observed that the peak vertical deformation, amplitude of fluctuation, and attenuation rate decrease as the distance from the point of vibration load application increases. At the base of the tunnel, the peak vertical deformation is 1.054 mm, while at distances of 2 m, 5 m, 8 m, 15 m, and 25 m from the tunnel base, the peak vertical deformations decrease to 0.963 mm, 0.844 mm, 0.762 mm, 0.557 mm, and 0.342 mm, respectively, representing reductions of 8.6%, 19.9%, 27.7%, 47.2%, and 67.6%, respectively. Furthermore, the vertical displacement after a single load applied to the tunnel exhibits a rebound trend, and all analysis points show displacement rebound after reaching the maximum vertical displacement. In terms of the magnitude of rebound after reaching the maximum vertical deformation, the farther the point is from the location of vibration application, the slower the rebound velocity and the flatter the  
Figure 19: Analyze the vertical deformation of the point.  
Figure 20: Analyze the peak vertical deformation of the point.  
trend. Combining the analysis of pore pressure discussed earlier, it can be concluded that the locations where the variation amplitude and rate of pore pressure are greater in the bottom soil layer of the tunnel correspond to larger vertical deformations in the soil mass.