## 4 Comparing Simulating Results with Monitoring Results
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Items**} & **Thickness of** & **Grouting** & **Grouting** & **Average** \\  & **Weak** & **Pressure, \(p_{g}\)** & **Filling Rate,** & **Seepage** \\  & **Underlying** & **(kPa)** & **GFR (\%)** & **Volume** \\  & **Layer, \(H_{s}\) (m)** & **(kPa)** & **(kPa)** & **(kPa)** \\ \hline Values & 2 & 280 & 150 & 2 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Parameters for simulating. ground uplift. However, this effect was not considered in the numerical simulation. In addition, the monitored consolidation occurred about three days after the shield tail passed, which was related to the coagulation time of the grouting. However, in the numerical simulation, the time for consolidation to occur was artificially set (six days after the shield tail passes through), and the grouting material hardening was not considered. The reason the simulated consolidation time was longer than that in the field is to fully present the whole process of settlement during construction. Moreover, the consolidation settlement in the field was larger than the simulation. This can be explained by the fact that the sub-consolidation settlement and the consolidation and cementation effects of grout were not considered in the numerical model, which are also main components of long-term surface settlement. After the segments were assembled, the deviation of the tunnel was monitored for three days, as shown in Figure 7. The results showed that the segment was in a continuous floating stage within three days after the segment was assembled, and the maximum floating amount reached 28 mm, which is consistent with the development of the simulation results. It should be noted that the floating amount of the segment in the field was larger than the simulated value. This was mainly related to the state of the grouting material around the segment. The longer the time and length of the segment lining in the liquid grouting material are, the greater the floating amount of the segment. The results indicated that the segment at the monitoring section was affected by the grouting material for about three days, which is longer than the assumed time and length of the grouting acted on the segment lining in the numerical model. The horizontal settlement trough of the ground surface after the shield machine passed completely during the construction period was compared with the field observation. As shown in Figure 8, the simulated surface settlement trough presented a standard bell-shaped curve, with a maximum settlement of \(-10.98\) mm directly above the tunnel axis. The simulated results were consistent with the value and distribution of the monitored surface settlement trough. However, the monitored surface settlement trough had a certain asymmetry, which was different from the simulation results. The possible reason is that the shield machine has a large horizontal axis deviation during the tunneling process, and the numerical model established in this paper does not consider the deviation of the shield machine from the tunnel axis. Figure 7: Simulated and monitored segment displacement time-history curves.