# Comprehensive Method to Test the Stability of High Bedding Rock Slope Subjected to Atomized Rain
## 5 Case Study
### Verification of Test Results with FEM  
#### 5.8.1 FEM Analysis  
To verify the test results of the comprehensive method, the finite element method was utilized to compare the slope failure process. The two-dimensional calculation grid graph of the left bank slope is presented in Figure 15.  
Figure 14: Typical curve of slope surface displacement (monitoring points near concrete plugs).  
The simulation range, load combination, and mechanical parameters utilized in the calculation were consistent with the model test. The finite element software ANSYS was utilized for nonlinear analysis of materials. The Drucker-Prager yielding criterion was utilized for strength criterion analysis. The rock utilized the solid45 element, and the concrete plug utilized the solid65 element. The model contained 9354 discrete elements and 11,476 nodes. The model coordinate system used the X-axis for the horizontal direction with the positive direction to the right, the Y-axis for the vertical direction with the positive direction pointing upward, and the Z-axis for the water flow direction with upstream as the positive direction.  
(1) Distribution characteristics of the displacement  
According to the relationship curves of the slope surface displacement (Figure 16), during the fourth to fifth steps (\(K_{\text{S}}=1.08-1.10\)), the displacement curve showed fluctuation. Prior to the 10 th step (\(K_{\text{S}}=1.20\)), the surface displacement of the slope was dominated by the vertical settlement toward the valley, and the displacement curve exhibited a steady increase in linear mode with a smaller displacement. During the 16 th to 18 th steps (\(K_{\text{P}}=1.295-1.401\)), most of the curves began to turn back, and the displacement gradually increased. The settlement displacements showed apparent increases in both the X and Y directions. The displacements of #10 and #24 in the X direction were very significant, as were #1 and #2 in the Y direction.  
(2) Plastic failure analysis  
According to the distribution graph of the plastic zone (Figure 17), it was found that under the application of slope self-weight, plastic zones showed up at the exit of C3-1 and LS337. The intersected locations of the structural planes between C3-1 and J108 and between LS337 and J110 all showed relatively small plastic zones. When the slope model was uplifted 5\({}^{\circ}\) (\(K_{\text{P}}=1.243\)), the plastic zone on the cracked  
Figure 16: Typical curve of slope surface displacement. (**a**) Horizontal displacement; (**b**) vertical displacement.  
Figure 15: Two-dimensional numerical calculation grid graph of the slope.  
plane J\({}_{110}\) penetrated C\({}_{3\text{-}1}\) and extended to LS\({}_{337}\), and the cracked plane J\({}_{136}\) was penetrated. Thus, multiple slip blocks were formed. When the slope model was uplifted 10\({}^{\circ}\) (\(K_{\text{P}}\) = 1.512), the plastic zones of various structural planes grew, penetrated, and intersected each other, and the slope showed global instability.  
(3) Safety factor assessment  
In numerical calculations, when the shear strength of the C\({}_{3\text{-}1}\) and LS\({}_{337}\) decreased by 1.2 and the angle was uplifted by 6\({}^{\circ}\)-7\({}^{\circ}\) (\(K_{\text{sp}}\) = 1.295-1.347), the curve of the characteristic point gradually showed turning, and displacement showed a significant increasing trend. This indicated the instability failure of the slope. Therefore, \(K_{\text{sc}}\) is as follows:  
\[K_{\text{sc}}=1.20\times(1.295-1.347)=1.554-1.617\]