## 3 Midas GTS Simulation Process and Results
### Load and Constraint  
#### 3.3.1 Construction Load  
The foundation of the current tunnel experiences deformation and displacement solely during the excavation of the foundation pit and the installation of support, excluding any consideration of ground overload. The hydraulic thrust of the shield tunneling machine ranges from 800 to 1200 T, representing the total power provided by the hydraulic cylinder to the shield machine. For our analysis, we adopted a median value of 1000 T as the thrust \(F\) of the shield tunneling machine. This thrust \(F\) encompasses the pressure that \(F_{1}\) exerted on the palm surface through the cutter head of the shield machine, the friction resistance \(F_{2}\) of the jack to overcome the shield shell and surrounding strata, the friction resistance \(F_{3}\) between the segment and the shield tail, and the traction resistance \(F_{4}\) of the truck and supporting equipment [53]. \[F=F_{1}+F_{2}+F_{3}+F_{4}\] \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Soil**} & \multirow{2}{*}{**Poisson Ratio**} & \multicolumn{2}{c}{**Natural Unit Weight**} & \multirow{2}{*}{\(F_{50}^{\text{ref}}\)} & \multirow{2}{*}{\(F_{\text{ood}}^{\text{ref}}\)} & \multirow{2}{*}{\(F_{\text{un}}^{\text{ref}}\)} \\  & & \(\boldsymbol{\gamma\) (kN/m3)}\) & & & & \\ \hline Miscellaneous fill & 0.38 & 17.5 & 3 & 3 & 9 \\ Powdered sand & 0.28 & 19.3 & 14 & 14 & 42 \\ Silt with sandy silt & 0.3 & 19.2 & 15 & 15 & 45 \\ Sandy silt & 0.3 & 19.6 & 7 & 7 & 21 \\ Silty clay & 0.33 & 19.1 & 12 & 12 & 36 \\ Clay & 0.3 & 19 & 10 & 10 & 30 \\ Puddingstone & 0.3 & 20.2 & 40 & 40 & 120 \\ Strongly weathered rock & 0.23 & 25 & 30 & 30 & 150 \\ Moderately weathered rock & 0.13 & 25.2 & 50 & 50 & 300 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Soil material attributes. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Structure Name**} & \multirow{2}{*}{ \begin{tabular}{c} **Element** \\ **Type** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Elasticity** \\ **Modulus** \\ **(kPa)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Poisson** \\ **Ratio** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Volumetric** \\ **Weight** \\ \(\boldsymbol{\gamma\) (kN/m3)}\) \\ \end{tabular}  } & \multirow{2}{*}{**Material**} & \multirow{2}{*}{**Sectional Dimensions**} \\ \cline{1-1} \cline{5-6} Crown beam and first concrete & 1D beam & & & & & \\ support & element & & & & \\ Third concrete support of & 1D beam & & & & & \\ shield initiation well and waist & 1D beam & & & & & \\ beam & element & & & & & \\ Collar beam & 2.80 & 107 & 0.2 & 23.5 & C35 & \begin{tabular}{c} Filled rectangle: H = 0.6 m \\ and B = 0.8 m \\ \end{tabular}  \\ \ \begin{tabular}{c} Stellar beam \\ Steel support of shield \\ initiation well \\ Steel support of standard \\ section \\ 2D plate \\ element \\ 2D plate \\ element \\ 2D plate \\ element \\ 2D plate \\ element \\ 2D plate \\ element \\ 3D plate element \\ 3D plate \\ element \\ \end{tabular}  &
\begin{tabular}{c} 2.80 \(\times\) 10\({}^{7}\) \\ 0.2 \\ 2.80 \(\times\) 10\({}^{8}\) \\ 0.2 \\ 2.80 \(\times\) 10\({}^{8}\) \\ 0.3 \\ 2. The positive propulsive resistance \(F_{1}\) acting on the central axis of the soil palm surface was defined as equal to half of the horizontal water and soil pressure. Moreover, 50% of the water and soil pressure between the top and bottom of the shield machine was chosen as \(F_{1}\), and an additional 15 kPa was added on this basis. In this study, \(F_{1}\) = 128 kPa [54; 55]. The thrust's remaining part was simplified to the resistance of the soil acting on the shield line element. \[ \begin{array}{ll}F^{\prime}&=\frac{F}{\pi r^{2}}-F_{1}\\ &=\frac{10,000\text{ kN}}{3.14\times 3.1\times 3.1\text{ m}^{2}}-113\text{ kPa}\\ &\approx 218\text{kPa}\end{array}