## 4 Comparing Simulating Results with Monitoring Results  
The section of the 240 th ring of the left line tunnel was set as the monitoring section LR240. To verify the reliability of the numerical model, the model calculation results were compared with the field monitoring results. Table 5 showed the parameters required for numerical model calculation, which was consistent with the construction parameters corresponding to the on-site monitoring section LR240. Considering the large disturbance during the construction process, the leakage conditions of the tunnel adopted the four-level standard, which indicated that the average seepage volume of the entire tunnel project was 2 L/(m\({}^{2}\cdot\)d). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Density (g/cm\({}^{3}\))** & **Elastic Modulus (kPa)** & **Poisson’s Ratio** \\ \hline \hline Lining & 2.5 & 2.76\(\times 10^{7}\) & 0.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Parameters of the grouting materials. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Density (g/cm\({}^{3}\))** & **Elastic Modulus (kPa)** & **Poisson’s Ratio** \\ \hline \hline Lining & 2.5 & 2.76\(\times 10^{7}\) & 0.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Parameters of the lining. During tunnel construction, the ground settlement and tunnel deviation of the monitoring section LR240 were recorded and compared with the simulated results in Figures 5 and 6. To distinguish between short-term and long-term settlement, the short-term settlement mentioned in this paper refers to the settlement that occurs during the period directly affected by the shield construction steps, including cutter head excavation, shield body passage, lining construction, and grouting. The long-term settlement refers to the settlement that occurs during the consolidation period of soil and slurry after all construction steps are completed. Thus, the 240 th ring segment lining that was assembled corresponds to the sixth day in the model. In addition, the first 12 days were defined as the construction phase, in which the consolidation function was not turned on in the model; 13 to 90 days were defined as the consolidation phase, in which the consolidation function was turned on in the model. As the filed observations show in Figure 6, there was a settlement in the ground surface, which was basically within 5 mm, before the segment lining was assembled. This part of the settlement is mainly due to volume loss in front of the excavation front and around the shield periphery. After the segments were assembled, the surface began to bulge and reached the maximum bulge value of 5 mm after three days, which was caused by the rebound effect of unloading soil and grouting material. Furthermore, the results indicated that the grouting material and disturbed soil around the segment began to consolidate and coagulate after three days. As a result, the consolidated settlement occurred. Although the secondary grouting will cause a rebound of the formation, consolidation settlement will continue to occur subsequently. Compared with the simulation results, it can be found that the time-history law of the simulation results and the monitoring results were consistent, which can be summarized as follows: before the segment was assembled, the stratum subsided, and after assembling, the stratum first uplifted and then subsided. However, there were some differences between numerical simulation and field monitoring data in short-term settlement and long-term settlement. First, the simulated subsidence when the shield tail passes was larger than the monitored value. This is mainly because the shield often excavates in the soft soil with the head loaded and the tail raised, which is due to the heavy cutter head and the low strength of the subsoil, and the raised tail will lift the  
Figure 6: Simulated and monitored surface displacement time-history curves.