## 3 Results and Discussion
### Numerical Simulation Analysis
#### 3.4.3 Monitoring Point Data Analysis  
In order to compare with the slope stability criterion obtained from the physical model test, the axial force monitoring points (F-1-F-9) were arranged at the end of the anchor bolt in the numerical model, and the pore water pressure monitoring points P-1-P-3 were set in the weathering transition zone. Figure 17a shows the variation of pore water pressure at monitoring points. The geological body of the strongly weathering and weakly weathering interface was not saturated from Stage-1 to Stage-2. The pore water pressure first increased at monitoring point P-3 after 10 min of loading in Stage-3. During Stage-4, the pore  
Figure 16: Evolution of displacement magnitude contour: (**a**) End of Stage-1; (**b**) End of Stage-2; (**c**) End of Stage-3; (**d**) End of Stage-4.  
Figure 15: Evolution of pore water pressure contour: (**a**) End of Stage-1; (**b**) End of Stage-2; (**c**) End of Stage-3; (**d**) End of Stage-4.  
water pressure at monitoring points P-2 and P-1 increased. The evolution of pore water pressure shows that the geologic body near the slope surface was saturated earlier, which is consistent with the vertical seepage law of rainfall. Figure 17b shows the variation of the anchor bolt axial force. During 0-10 min, the displacement of the slope was concentrated on the front block in the strongly weathering zone, so the axial force increased the fastest at monitoring points F-1-F-3. During 20-50 min, the axial force at F-4-F-9 monitoring points increased significantly, indicating that the deformation of the upper part of the slope increased. During the stage of hydraulic fluctuation, the increase of displacement of the front block caused a significant increase of anchor axial force at F-1-F-3 monitoring points, which is close to the sudden increase of axial force in the physical model test.  
To verify the stability criterion of the slope weathering transition zone proposed in the physical model test, the data fitting analysis was carried out by using the axial force and pore water pressure data of the bolt extracted from the numerical simulation. The results show that the relationship between the pore water pressure at measuring point P-3 and the axial force of some monitoring points can be characterized by the Logistic function. Figure 18a,b show the fitting results of the axial force at monitoring points F-1 and F-2 and the pore water pressure at monitoring point P-3. The fitting parameters of the remaining monitoring points are summarized in Table 9.  
Since the nonlinear flow behavior in the broken rock mass was not considered in the numerical simulation, the comparison of the test results shows that there is a significant difference between the monitoring criteria obtained from the numerical simulation and the model test results. In addition, the unloading response characteristics of ITS were not realized in the numerical simulation. In future research, a constitutive model for  
Figure 17: Monitoring data variation at monitoring points: (**a**) Variation of pore water pressure; (**b**) Variation of anchor bolt axial force.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Variable**} & \multicolumn{4}{c}{**Constant**} & \multicolumn{1}{c}{**R2**} \\ \hline
**A Data Set From** & **P Data Set From** & \(\mathbf{C_{1}}\) & \(\mathbf{C_{2}}\) & \(\mathbf{P_{0}}\) & \(\mathbf{n}\) & \\ \hline F-3 & P-3 & 102.85 & 255.55 & 4.94 & 2.71 & 0.98 \\ F-4 & P-3 & 136.32 & 1035.87 & 6018.94 & 0.40 & 0.99 \\ F-6 & P-3 & 118.38 & 216.52 & 2.42 & 0.79 & 0.99 \\ F-8 & P-3 & 124.57 & \(5.71\times 10^{5}\) & 6.08 & 0.57 & 0.92 \\ \hline \hline \end{tabular}
\end{table}
Table 9: Numerical results fitting parameters.  
the corresponding ITS unloading response could be developed to study the application potential of slope stability monitoring in more detail.