## 3 Calculation Results and Analysis
### Analysis of Calculation Results in Case 3  
The horizontal and vertical displacement maps of the model as a whole, for when the hanging wall settlement is 10 cm, 20 cm, 30 cm, 40 cm, and 50 cm, are shown in Figure 10. It is observed that when the hanging wall settlement increases, the displacement and deformation of the soil and the overpass increase, and the displacement and deformation of the two are related to the relative position of the ground fissure; the closer to the ground fissure, the greater the influence, and vice versa. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Vertical**} & \multicolumn{2}{c}{**Left Side Across**} & \multicolumn{2}{c}{**Middle Across**} & \multicolumn{2}{c}{**Right Side Across**} \\
**Settlement** & **Left Side** & **Right Side** & **Left Side** & **Right Side** & **Left Side** & **Right Side** \\ \cline{2-7}
**/cm** & **Displacement** & **Displacement** & **Displacement** & **Displacement** & **Displacement** & **Displacement** & **Displacement** \\  & **/mm** & **/mm** & **/mm** & **/mm** & **/mm** & **/mm** & **/mm** \\ \hline
10 & 0.742 & \(-\)2.304 & \(-\)2.304 & \(-\)2.304 & \(-\)8.290 & \(-\)8.290 & \(-\)10.492 \\
20 & 1.650 & \(-\)4.478 & \(-\)4.478 & \(-\)16.368 & \(-\)16.368 & \(-\)20.641 \\
30 & 2.548 & \(-\)6.397 & \(-\)6.397 & \(-\)24.479 & \(-\)24.479 & \(-\)30.728 \\
40 & 3.432 & \(-\)8.172 & \(-\)8.172 & \(-\)32.609 & \(-\)32.609 & \(-\)40.811 \\
50 & 4.293 & \(-\)9.894 & \(-\)9.894 & \(-\)40.762 & \(-\)40.762 & \(-\)50.903 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Vertical displacement of each span of the box girder. Figure 8: The inclination of box girder under different settlement amounts. Figure 7: The inclination of each bridge pier under different settlement amounts. Figure 9: Longitudinal stress of box girder under 10 cm settlement. The horizontal displacement of the node at the top and bottom positions of the bridge pier is determined (Table 7). The displacement difference of each pier at different settlement amounts is shown in Figure 11. When the settlement amount is 50 cm, the tilt of Pier No. 1 in the lower plate of the ground fissure is the largest in the settlement process, which is 0.45%, followed by Pier No. 2 in the lower plate of the ground fissure, with a tilt of 0.32%. Figure 10: Overall displacement map under different settlements of the hanging wall of the ground fissure: (**a**) S = 10 cm; (**b**) S = 20 cm; (**c**) S = 30 cm; (**d**) S = 40 cm; (**e**) S = 50 cm. The tilt of Pier No. 3 in the lower plate of the ground fissure is 0.36%, and the tilt of Pier No. 4 located in the hanging wall is the smallest, which is 0.12%. It is observed that when the vertical settlement of the ground fissure exceeds 10 cm, the tilt of the bridge pier may exceed the specification requirement. The vertical displacements of the nodes at the left and right end positions of each span of the extracted box girder are shown in Table 8, and the vertical displacement differences of each box girder at different settlement amounts are shown in Figure 12. When the settlement amount is 50 cm, the tilt of the right-span box girder across the ground fissure is the largest (1.20%); the tilt of the middle-span box girder under the ground fissure is the second largest (0.38%); and the tilt of the left-span box girder under the ground fissure is the smallest (0.017%). When the vertical settlement of the ground fissure exceeds 10 cm, the tilt of the right span across the ground fissure exceeds the specification limit. During the settlement of the hanging wall of the ground fissure, a large longitudinal stress is generated in the box beam. The stress map for when the settlement is 10 cm is shown in Figure 13.  
It can be seen that the maximum tensile stress in the box girder is 5.6 MPa, while the ultimate tensile stress of C50 concrete is 5 MPa. When the settlement of the ground fissure joint activity is greater than 10 cm, tensile damage occurs in the box girder concrete.