# Calculation Method of New Assembled Corrugated Steel Initial Support Structure of Highway Tunnel
## 4 Practical Engineering Application
### Comparative Analysis of Monitoring Data
#### 4.3.2 Convergence around the Tunnel  
The convergence measurement lines around the tunnel of the corrugated steel initial support test section are depicted in Figure 15. Measuring lines AE and BF were specifically chosen to track the evolution of convergence of the secondary lining structure over time in this study. From Figure 15, the following observations are noted: (1) Measuring line AE shows a gradual increase in convergence within one month after the completion of secondary lining construction, stabilizing eventually at 2.44 mm; (2) Measuring line BF exhibits a similar pattern with convergence increasing gradually over two weeks post-secondary lining completion, followed by slight fluctuations before stabilizing at 2.41 mm; (3) Following the completion of the secondary lining, the convergence deformation of the tunnel remains minimal, suggesting a relatively stable tunnel structure.  
The numerical simulation of vertical deformation around the Qipanshan Tunnel is illustrated in Figure 16. Following the completion of secondary lining pouring, monitoring data from the convergence measuring line around the tunnel indicates displacement increments in the numerical model from initial secondary lining construction to final stabilization. The convergence data from lines AE and BF in the  
Figure 14: Monitoring curve of typical measuring points of CSP surface strain.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \begin{tabular}{c} **Number of** \\ **Measuring Points** \\ \end{tabular} & \
\begin{tabular}{c} **Monitoring Value/\(\mu\epsilon\)** \\ \end{tabular} &
\begin{tabular}{c} **Corresponding Value of** \\ **Numerical Simulation/\(\mu\epsilon\)** \\ \end{tabular} & **Error** \\ \hline
2-3 & \(-351\) & \(-355\) & \(2\%\) \\
5-2 & \(-303\) & \(-260\) & \(14\%\) \\ \hline \hline \end{tabular}
\end{table}
Table 5: Comparison table of CSP strain.  
extracted and compared against field monitoring results, with the comparative findings presented in Table 6.  
From Table 6, it is observed that the relative error between the numerical simulation results of tunnel convergence and the field monitoring data is below 20%. This indicates a favorable agreement between the two datasets regarding tunnel convergence.  
In summary, based on the comparative analysis of the aforementioned monitoring data, the calculation method developed in this study for the corrugated initial support structure effectively simulates structural deformation, stress, and other pertinent engineering considerations. The method demonstrates its correctness and reliability in addressing practical engineering challenges.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Field Monitoring**} & \multicolumn{2}{c}{**Numerical Simulation**} & \multicolumn{2}{c}{**Error**} \\ \hline \multirow{2}{*}{**Measuring Line**} & **Cumulative** & \multicolumn{2}{c}{**Relative Displacement/mm**} & **Displacement** & \multirow{2}{*}{**Displacement**} \\  & **Displacement/mm** & **After Stabilization** & **After Secondary Lining** & **Increment/mm** & \\ \hline AE & 2.44 & 4.35 & 2.07 & 2.28 & 8\% \\ BF & 2.41 & 2.89 & 0.98 & 1.91 & 20\% \\ \hline \hline \end{tabular}
\end{table}
Table 6: Comparison table of monitoring–numerical simulation for convergence around the tunnel.  
Figure 16: Vertical deformation around the tunnel.  
Figure 15: Monitoring curve of typical tunnel convergence measuring lines of convergence.