## 3 Three-Dimensional Numerical Model
### Finite Element Calculation Parameters  
#### 3.2.1 Static Loads for New Tunnel Excavation  
1. Basic parameters  
Mudstone and malmstone specimens were taken from a typical Class IV perimeter rock section of the Shiqian Wanshoushan Highway Tunnel, and density tests, uniaxial compression and deformation tests, and triaxial compression tests were conducted [6]. Table 1 shows the parameters of the peripheral rock support of the Shiqian Wanshoushan highway tunnel. As shown in Figure 5, the peripheral rock support of the Shiqian Wanshoushan highway tunnel is shown. Anchor support is discounted to the modulus of elasticity of the rock body in the reinforced area by stiffness, the steel frame and grid support are discounted to the initial lining of sprayed concrete by stiffness, and the reinforced area of rock anchors is estimated according to [PERSON]'s formula [28], the steel frame or grid discounting formula:  
\[E_{C}=E_{c0}+S_{g}\times E_{g}/S_{c} \tag{1}\]  
Figure 4: Solid model building steps: (**a**) geological topographic map; (**b**) CAD digitization; (**c**) TGM ground surface; (**d**) stratigraphic profile; (**e**) 3D solid model. where: \(E_{C}\) is the modulus of elasticity of the spray concrete after conversion (MPa); \(E_{c0}\) is the modulus of the elasticity of the original spray concrete (MPa); \(S_{g}\) is the steel frame or grille frame cross-sectional area (m\({}^{2}\)); \(E_{g}\) is the modulus of the elasticity of the steel frame or grill (MPa); and \(S_{c}\) is the cross-sectional area of the concrete (m\({}^{2}\)). The anchor support discount formula:  
\[E_{r}=E_{r0}+V_{b}\times E_{b}/V_{r} \tag{2}\]  
where \(E_{r}\) is the modulus of the elasticity of the rock mass after conversion (MPa); \(E_{r0}\) is the modulus of the elasticity of original spray concrete (MPa); \(V_{b}\) is the volume of the anchor rods in the support area (m\({}^{3}\)); \(E_{b}\) is the modulus of the elasticity of the anchor rod (MPa); and \(V_{r}\) is the volume of the rock body in the support area (m\({}^{3}\)). The parameters of the mudstone and malmstone rock mass and the discounted anchor support and steel frame grating support are shown in Table 2. \begin{table}
\begin{tabular}{c} T76L self-propelled anchor + \\ small conduit in advance \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Parameters of the peripheral rock support of the Shiqian Wanshoushan highway tunnel. Figure 5: Cross-section of the peripheral rock support of the Shiqian Wanshoushan highway tunnel. 2. Numerical simulation process
1. The corresponding rock properties are assigned to the strata, and the initial ground stress field is balanced. There is no influence of tectonic joints in the cross-section tunnel project, and the ground stress is considered according to the initial self-gravitational stress field. 2. Simulate the excavation of the whole section of the existing railroad tunnel, apply initial support and secondary lining, and zero the displacement field. 3. Excavation of the new highway tunnel. Tunnel each excavation at a footage of 2 m after the excavation for the initial support and secondary lining in order to facilitate data analysis for multiple excavation steps as a whole encapsulated into different data results extracted when the step is Si. Set the left side of the tunnel for the first excavation of the tunnel, from the inlet (left) to the exit (right) excavation, the right side of the tunnel for the excavation after the front and back of the tunnel difference of 3 Si, Si, and Nos. for the S\({}_{1}\), S\({}_{2}\), S\({}_{3}\), and S\({}_{20}\),...S\({}_{20}\). The left holes S\({}_{1}\) and S\({}_{17}\) and the right holes S\({}_{4}\) and S\({}_{20}\) are the time step of going to the boundary effect, which is 90 m, respectively.