## 5 Three-Dimensional Numerical Simulations of the Huaipa Landslide
### Landslide Creep Deformation and Disaster Evolution Mechanism
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & **Elastic** & \multirow{2}{*}{\begin{tabular}{c} **Moulus** \\ **(GPa)** \\ \end{tabular} } & **Poisson** & \begin{tabular}{c} **Unit** \\ **Ratio** \\ \end{tabular} & \begin{tabular}{c} **Cohesion** \\ **Weight** \\ **(kPa)** \\ \end{tabular} & \begin{tabular}{c} **Angle of** \\ **Internal** \\ **Friction (°)** \\ \end{tabular} & \begin{tabular}{c} **Kelvin** \\ **Shear** \\ **MODUus** \\ **(kPa-day)** \\ \end{tabular} & \
\begin{tabular}{c} **Kelvin** \\ **Shear** \\ **MODUus** \\ **(kPa-day)** \\ \end{tabular} &
\begin{tabular}{c} **Maxwell** \\ **Shear** \\ **MODUus** \\ **(kPa-day)** \\ \end{tabular} \\ \hline Sliding mass & 0.25 & 0.32 & 21.2 & 150 & 32 & & & & \\ Bedrock & 75 & 0.26 & 27.1 & 310 & 39.7 & & & \\ Sliding zone & 0.15 & 0.32 & 20.9 & 130 & 32.1 & & & \\ Sliding zone & 0.15 & 0.32 & 20.9 & 94 & 23 & \(8.44\times 10^{3}\) & \(5.00\times 10^{2}\) & \(6.50\times 10^{3}\) & \(1.20\times 10^{6}\) \\ Sliding zone & 0.105 & 0.33 & 21 & 21 & 23.9 & \(8.84\times 10^{3}\) & \(6.67\times 10\) & \(1.00\times 10^{3}\) & \(3.26\times 10^{5}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Mechanical parameters of the Huaipa landslide used for the numerical analysis. Figure 13: Calculation model (Profile A-A\({}^{\prime}\) is the main sliding section). Displacement monitoring points were set up along the landslide slope surface and location of the slip zone, as shown in Figure 15a. The monitoring results are shown in Figure 15b,c. Under natural conditions, the slope was found to be in a stable creep state and the maximum deformation rate of the slope was approximately 9 cm/year. After rainfall saturation, the landslide deformation increased rapidly. However, the landslide deformation rate decreased gradually over time and the landslide activity tended to stabilize. The deformation curves and displacement of the slope surface and sliding zone are shown in Figure 16, indicating similar characteristics at both locations. The deformation of the slope body was largest at positions a2 and b2, and the deformation gradually decreased toward the slope foot. After excavation, the slope foot deformation was considerably reduced at positions a6 and b6, which indicates that the landslide was caused by the thrust load in the creep sliding process. Figure 14: Deformation evolution process. (**a**) Excavation (March 2013) elastoplasticity analysis, (**b**) Natural state (creep time = 5 days), (**c**) Natural state (April 2014), (**d**) Saturation state (creep time = 395 days), (**e**) Saturation state (2 May 2014), (**f**) Displacement vector (creep time = 422 days). Figure 16: Deformation curves of the landslide slope surface and sliding zone. (**a**) Slope surface displacement, (**b**) Sliding zone displacement. Figure 15: Monitoring curves of the slope displacement with time. (**a**) Monitoring point locations, (**b**) Slope surface displacement, (**c**) Sliding zone displacement. Monitoring points were positioned in downward intervals of 5 m in the rear (point a2), middle (point a4), and front (point a6) regions of the slope (Figure 17). Figure 17 shows that the sliding zone displacement was less than the sliding mass displacement; that is, the bedrock showed no significant displacement changes. The sliding zone deformation rate was also less than that of the sliding mass. At the back of the landslide, the maximum deformation occurred 5 m above the sliding zone. In the middle of the landslide, the deformation within the sliding mass was essentially the same and extended over the sliding area. At the front edge of the landslide, the deformation rate of the sliding mass was slightly less than that of the sliding zone, indicating that the location of the slope foot played a role in blocking the sliding.