## 6 Interactions between Segments along the Longitudinal Direction
### Outward Radial Deflection Error  
In the synchronous propulsion and assembly mode, the normal assembly of the segment will cause the segment to exhibit radial deflection, and the outward radial deflection error of the segment can reduce the possibility of segment damage to a certain extent. When a segment is deflected radially outward, the stress concentration effect on the packer is reduced, so the compression damage factor of the segment will not change abruptly. With the increase of the error, the compression damage factor increases with a more moderate trend. The maximum damage to the segment is concentrated on both sides of the middle segment, mainly showing the extrusion damage of the two sides and the compression damage of the segment gasket (Figure 16 and Table 5). When the initial segment is at the bottom, the outward radial deflection has the greatest influence on the damage to the segment. When the deflection is 0.41\({}^{\circ}\), the segment will be damaged, as shown in Figure 17. The main reason for this is that the newly assembled segment is more prone to outward deflection when it is at the bottom than other initial positions. There are no other supports between the segment rings to provide additional support when radially deflected outwards, so the sides of the gasket are more prone to damage. When outward deflection occurs, the maximum tensile damage factor of the segment is 92.54%. Since the thrust is unchanged, the tensile damage of the segment is not greatly affected. Figure 15: Maximum opening of segment joints in the presence of inward deflection. \begin{table}
\begin{tabular}{c c c c} \hline
**Location** & **Assembly Process** & **Damage Angle (\({}^{\circ}\))** & **Destruction Location** \\ \hline \multirow{3}{*}{Top} & Assembly of the first segment & 1.20 & Both sides of segment \\  & Assembly of the second segment & 1.00 & Extrusion corner \\  & Assembly of the third segment & 0.58 & Extrusion corner \\ \hline \multirow{3}{*}{Lateral} & Assembly of the first segment & 1.10 & Both sides of segment \\  & Assembly of the second segment & 0.76 & Extrusion corner \\  & Assembly of the third segment & 0.58 & Extrusion corner \\ \hline \multirow{3}{*}{Bottom} & Assembly of the first segment & 0.58 & Both sides of segment \\  & Assembly of the second segment & 0.76 & Extrusion corner \\ \cline{1-1}  & Assembly of the third segment & 0.40 & Extrusion corner and middle of outer arc \\ \hline \end{tabular}
\end{table} 
Table 5: Damage to the segments. The outer joint width of the segment gradually decreases with the increase of the outward radial assembly error, as shown in Figure 18. During the segment assembly process, the joint quality of the segment is gradually improved, which means that the assembly process reduces the deflection freedom of the segment. The action position of the jack is distributed along the center of the bearing surface, and the gasket of the segment is closer to the outer side of the segment. Although the component force caused by the outward deflection error causes the segment to deflect to the outside, the component force is too small compared to the jack thrust in the synchronous propulsion and assembly mode. Therefore, under the outward radial deflection error of the segment, the influence on the maximum joint volume of the segment is small, and the maximum reduction is only 1 mm. Figure 16: Damage to segment in the presence of outward deflection when the asymmetric error angle is \(1.4^{\circ}\): (**a**) first segment assembly (%); (**b**) second segment assembly (%); (**c**) third segment assembly (%). (Take the segment at the bottom as an example.) the assembly process, the segment as a whole will show the same trend of inclination, and the extrusion effect will be superimposed. At this time, the segment will be damaged at a smaller error angle. The tensile damage factor of the segment also did not change greatly with the change of working conditions, and the peak value was 91.56%.