## 5 Comparison of Numerical Simulation Results to Measured Data  
In Figures 5, 6, 10 and 11, the results shown by the finite element software and the conclusions gathered from the analysis of the actual automatic monitoring data exhibit that the vertical and horizontal displacement laws of the existing tunnel structure are the same after multiple disturbances caused by the excavation of the foundation pit and the above-crossing of the newly built shield tunnel. Three representative sections were chosen: S513 and S528, intersecting the up-lines of Lines 7 and 1, and S520, corresponding to the middle of the foundation pit excavation face. By examining data from monitoring and numerical simulations at various construction stages, an in-depth analysis of the deformation patterns of the existing tunnel was conducted. Figure 12 shows that the measured values of the three typical sections of the existing tunnel exhibit settlement and uplift. After multiple disturbances, the measured values were in an upward state, and the values of changes in each construction stage were small and within the range \([-1.5,1.0]\). The numerical simulation results show that the excavation of the foundation pit has no obvious impact on the existing tunnel. However, after the new shield tunneling, the three typical sections of the existing tunnel were continuously uplifted. Figure 11: Horizontal displacement of tunnels subjected to multiple disturbances. (**a**) Horizontal displacement of up-line ballast bed subjected to multiple disturbances (**b**) Horizontal displacement of down-line ballast bed subjected to multiple disturbances. Furthermore, the floating value continued to increase. The final value was 4.7 times the measured value in the range \([2.0,2.5]\). Specific requirements were stipulated for the safety control index value of urban rail transit structures according to [43]. In this case, the warning value for the horizontal displacement and vertical displacement of existing tunnels was 10 mm, and the control value was 20 mm. According to the provisions of [44], the horizontal displacement control value of the existing tunnel in this case was 8 mm, and the vertical displacement was 10 mm. In summary, the control standard in this case was the acceptable limit of a horizontal displacement of 8 mm and vertical displacement of 10 mm. Automated monitoring was performed using the Leica GeoMoS software (GeoMoS-CH), which consists of two main parts: a monitor and an analyzer. The monitor has a well-developed measurement and calculation program that provides an ideal solution for applications requiring extremely high accuracy. According to the characteristics and relevant requirements of the project, automatic monitoring systems were established in the track running areas of the up-line and down-line, with monitoring lengths of approximately 200 m. Considering the accuracy of the automatic measurements of the total station, the monitoring alarm value, and the site conditions, two stations each were established in the up-line and down-line tunnels, totaling four stations, and two automatic monitoring networks were constructed. During the construction process, the survey team conducted 24 joint measurements of the data points and manually reviewed the automatic monitoring data 84 times. The results showed that the maximum difference between the automatic and manual monitoring results of the up-line and down-line was \(\pm\)2.1 mm, which is small and meets the requirements. The obtained results indicate that the foundation pit excavation induces the movement of the existing tunnel toward the foundation pit. Simultaneously, the new tunnel results in a horizontal displacement of three representative sections away from the foundation pit direction. Notably, the left-line of the new tunnel shield tunneling across the existing line has a slight effect on the horizontal displacement of the existing tunnel. The outcomes  
Figure 12: Comparison of the numerical simulation results and measured data of a typical section.