# Study on the Early Warning Methods of Dynamic Landslides of Large Abandoned Rockfill Slopes
## 5 Method Validation  
To check the feasibility and reliability of the landslide warning method of rockfill slopes, the last five landslides of two different types of landslides recorded during field monitoring were used to verify the landslide warning method. The waste rockfill slope was taken as the remaining broken surface after the previous landslide, and the slope angle was approximately 35-38\({}^{\circ}\). The excavation and loading speed during construction was approximately a 10-t load much truck loaded every 6-9 min. During the five landslide monitoring periods, there was no rainfall, the daytime temperature was about 20-25 \({}^{\circ}\)C, and the nighttime temperature was about 15-20 \({}^{\circ}\)C.  
The landslides occurred at 4:55 on 5 October 2013, 2:45 on 10 October 2013, 3:00 on 15 October 2013, 21:00 on 15 October 2013, and 9:38 on 16 October 2013. The final landslide areas were 450, 1000, 1100, 1600, and 1100 m\({}^{2}\), respectively. The specific records are shown in Table 5. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Waming Level**} & **Level 1** & **Level 2** & **Level 3** & **Level 4** \\ \cline{2-6}  & **Green** & **Yellow** & **Orange** & **Red** \\ \hline Slope Status & Stable & Relatively Stable & Relatively Unstable & Unstable \\ \hline \multirow{2}{*}{Early-warning Index} & Area change & & & & \\ rate index & rate index & \(<\)0.01 & 0.01–0.02 & 0.02–0.03 & \(\geq\)0.03 \\  & \(V^{*}_{-0.5}(t)\) (1/min) & & & & \\ \hline Evaluation & Stable & Relatively stable & Relatively dangerous & Dangerous \\ \hline \multirow{2}{*}{Dynamic regulation} & \multirow{2}{*}{Construct as normal} & Construct as normal while paying attention to the slopes & Pay close attention to the slope anomalies and adjust & Stop construction immediately and evacuate, and evacuate the original execution location, and avoid landslides \\ \cline{1-1} \cline{3-5}  & & Construct as normal while paying attention to the slopes & Pay close attention to the slope anomalies and adjust & Stop construction immediately and evacuate, and evacuate the original execution location, and avoid landslides \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Early warning classification and dynamic control method of the waste rockfill slope during excavation and transportation. Figure 11: The lower limit of the 95% confidence band for \(V^{*}_{-0.5}(t)\)  
First, the slope was initially classified according to whether there was a dense belt formed by the rolling of the slope or whether there was abnormally large-sized rubble in the middle of the slope. Landslides 44 and 53 conformed to the B1-type failure mode, while Landslides 67, 71, and 72 conformed to the B2-type failure mode. Then, ARIMA-SVR model was used to predict the variation trend of \(-0.5\) mm equal displacement cross-section area of these five landslides, and the results are shown in Figure 12. The average deviations between the predicted value and the measured value of five test landslides are shown in Table 6.  
According to Equation (2), the prediction results of five \(-0.5\) mm equal displacement bodies of five landslides were normalized. Then, the deformation rates of the cross-sectional area of the \(-0.5\) mm equal displacement bodies were calculated after normalization using Equation (3). The results are shown in Figure 13. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Landslide Number** & **Landslide 44** & **Landslide 53** & **Landslide 67** & **Landslide 71** & **Landslide 72** \\ \hline Average deviations (m\({}^{2}\)) & 9.8 & 11.9 & 15.3 & 21.2 & 10.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: The average deviations between the predicted value and the measured value of the five test landslides. Figure 12: The measured and predicted values of the cross-sectional area of the \(-0.5\) mm equal displacement bodies.