## 5 Monitoring Program and Results  
### Monitoring of Pipe Jacking Deformation  
Using a Leica TM30 total station and an extremely portable Focus S 350 3D laser scanner, field measurements of the relative deformation of the pipe sections were made,  
Figure 11: Horizontal displacement of pile foundation when pipe jacking is completed. (**a**) schematic diagram of pile foundation, (**b**) variation of horizontal displacement of pile foundation with depth. Figure 10: Horizontal displacement of pile foundation. (**a**) pipe jacking I, (**b**) pipe jacking II. with the major focus being on the cross-section deformation and longitudinal section deformation. The 3D laser scanner was selected with 10% reflectivity, and the single-point error of the instrument was less than 0.5 mm at a scanning distance of 25 m or less [21]. When entering and exiting the hole reinforcement area, entering the normal advancement area, and getting close to the viaduct piles, the pipe jacking section will exhibit various deformation characteristics. According to the development of pipe jacking II, the 25 th, 26 th, and 31 st rings of the pipe section are chosen as the monitoring objects to conduct on-site testing in order to explore the convergence deformation law of the pipe section under various construction situations. The initial state of the pipe sections is determined to be the initial value downhole measured by a total station (rather than out of the hole), and the relative deformation of each pipe section is measured under the working conditions of entering the reinforcement zone, normal advancement zone, and close to the viaduct piles, respectively. The actual measurement schedule is shown in Table 3.  
There are two methods utilized to monitor soil displacement: the surface settlement brought on by pipe jacking work and the deep lateral displacement of the earth near the bridge piles. The downhole observed values of lateral and radial deformation are used as the initial values to explore the convergence deformation law of the pipe segment while it is progressing. The deformation values of different pipe sections used in pipe jacking II are shown in Table 4. It is evident that the pipe section's transverse diameter gradually increases from the downhole into the reinforcement zone and then to the normal propulsion zone, and the transverse directions of the pipe sections for the 25 th and 26 th rings slightly change after passing under the elevated pile foundation's influence. This agrees with the outcomes of the numerical simulation's investigation of the pile foundation's impact on the pipe sections. As of the completion of the building of pipe jacking I, the lateral and radial deformation curves of pipe sections along the jacking direction are compared with the outcomes of total station and 3D laser scanning, as illustrated in Figure 12. The results of the numerical simulation are essentially consistent with the measured values obtained from 3D laser scanning and the total station, and the results of the pipe section radial deformation are also largely consistent, which further verifies the applicability and accuracy of the simulation results. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Serial** & **Starting** & **25 January** & **5 February** & **18 February** & **Cumulative Deformation** \\
**Number** & **Value** & **2020** & **2020** & **2020** & **Deformation** \\ \hline The 25 th ring & 9307.6 & +19.9 & +5.7 & \(-\)4.8 & +20.8 \\ The 26 th ring & 9329.7 & +6.1 & +8.5 & \(-\)1.0 & +13.6 \\ The 31 st ring & 9327.5 & / & +3.3 & +2.5 & +5.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Transverse opening of different pipe sections (unit: mm).