## 3 Numerical Modeling and Parametric Analysis Parameter Selection
### Parametric Analysis Modeling Case Determination  
In order to further explore the influence of different slope geometry parameters, consolidation geometry parameters, and different mechanical parameters on the factor of the safety of the horizontal consolidated slopes containing the MJS, the authors further synthesized the following parameters: the slope release angle of the excavation face, the geometric parameters of the reinforcement (height of reinforcement H, spacing of reinforcement D), the strength enhancement factor of the reinforcement compared with that of the original soil, and the strength enhancement factor of the original soil between the reinforcement to investigate in detail the stability of the slopes containing the MJS horizontal reinforcement in different cases. During the construction of the Guiqiao Road Station project, the size of the corresponding excavation section was 22.4 m \(\times\) 7.8 m. When considering step excavation and sub-silo excavation, the width of the excavation face of the upper step is estimated to be about 7 m. Based on the pipe curtain excavation section of Guiqiao Road Station, the upper and lower step method was used during the actual excavation process of Guiqiao Road Station. The overall height of the excavation face was 7.8 m. During the excavation process of each step, the corresponding height of the excavation face is respectively between 3 and 4 m. During the excavation process, on the premise of ensuring safety, in most actual excavation projects, the grading angle of the excavation face is between 60\({}^{\circ}\) and 75\({}^{\circ}\). When it is necessary to specifically control the deformation of the tunnel face and the deformation and settlement of the surrounding tunnels, at this time, the grading angle of the excavation face is generally 45\({}^{\circ}\). Figure 5: Geometric model of the slope under typical Case 2 and the shear strain increment cloud after analysis: (**a**) geometric model of the slope and (**b**) zone displacement cloud. Combined with the general situation of tunnel sloping excavation and the special value of engineering excavation face sloping, take 5\({}^{\circ}\)-10\({}^{\circ}\) as the interval of value and take the excavation face sloping angle as 45\({}^{\circ}\), 50\({}^{\circ}\), 60\({}^{\circ}\), 70\({}^{\circ}\), 80\({}^{\circ}\), 90\({}^{\circ}\) in order to analyze the influence of different excavation face sloping angles on the stability of the excavation face. In Gutiqiao Road Station, the height and width of the excavation face in the actual project are taken as the main constraints of the project and the parameters of the solidification arrangement, so the influence of different reinforcement arrangements or installations or construction heights, H; solidification spacings, D; and the number of layers of solidification arrangement on the stability of the excavation face is analyzed. The corresponding geometric schematic diagram is shown in the following Figure 6.  
The geometric cases of this parametric analysis are detailed in the following Table 1, in which the spacing, D, of the reinforcement and the height, H, of the reinforcement area are the spacing between the outer edge of the reinforcement and the spacing between the outer edge of the reinforcement and the bottom of the excavation face, respectively, and it should be noted that when the double-layer reinforcement arrangement is carried out, the distance between the two layers of the reinforcement is uniformly taken as 0.5 m for the sake of simplifying the analysis and calculation, and no change in the value is made. Figure 6: Numerical model of Flac at the excavation face under different cases: (**a**) numerical model of excavation face soil when laying out a layer of added MJS zone and (**b**) numerical model of excavation face soil when laying out two additional layers of MJS zone.