## 4 Test Phenomena Analysis  
### Description of the Test Phenomena  
The centrifugal tests for these three slope models with different angles indicated that all three slope models demonstrated the phenomenon of toppling deformation under the self-weight stress (centrifugal force) field. The deformation characteristics and evolution processes exhibited the same toppling deformation and failure but different deformation degrees and development evolutions due to the different slope angles. The specific test phenomena are described as follows:  
With increasing centrifugal acceleration, toppling deformation of the rock strata near the slope surface began to appear and increased slowly towards the free face under gravity at the initial stage of the test. The slope models indicated a tendency towards overall toppling, which provided space for deformation at the rear of the slope models. As a result, major settlement deformation occurred at the trailing edge of the slope and formed certain settlement grooves. Additionally, a small number of shear fractures were observed inside \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{1}{c}{**Rock Similarity Index**} & \multirow{2}{*}{**Density (g/cm\({}^{3}\))**} & **Elastic Modulus (MPa)** & **Compressive** & **Tensile Strength (MPa)** & **Chesion (kPa)** & **Internal Fiction Angle (\({}^{\circ}\))** \\ \hline \multirow{4}{*}{Prototype} & Metamorphic & 2.42 & 300 & 15 & 1.75 & / & / \\  & sandstone & / & / & / & / & 35 & 16 \\  & Metamorphic & 2.38 & 2800 & 14.8 & 1.84 & / & / \\ Model & Landscape & / & / & / & / & 34.5 & 15.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Physical and mechanical parameters of prototypes and similar materials. the slope due to the interlayer shear dislocation. No signs of tensile cracking appeared in the slope models, and the dip angle of the rock strata did not change obviously in this stage. Among the three model slopes, the model with a slope angle of 75\({}^{\circ}\) had the fastest response to toppling deformation and the largest settlement (Figure 6c), followed by those of 65\({}^{\circ}\) and 55\({}^{\circ}\) (Figure 6a,b). The author concluded that the larger the slope angle is, the more readily toppling deformation occurs in the slope models and the more conspicuous the response of the settlement at the trailing edge of the slopes is under identical geological conditions. With the gradual increase in centrifugal acceleration, besides the shear effect, the tensile effect between the rock strata gradually increased, causing tensile cracks in the rock mass to appear at the crest of the slope near the free face. The rock strata generated stress concentrations under the self-weight stress and intensified the compression of the overlying rock strata, and toppling bending rupture occurred first at the slope foot. The toppling deformation of the overlying rock strata, without support at the slope foot, intensified and began to form a \"toppling bending\" scenario under gravity. During this process, we found that the model with a slope angle of 55\({}^{\circ}\) exhibited a certain breaking and rupturing of rock strata only at the slope foot and the other parts were still inconspicuous. That of 65\({}^{\circ}\) already presented slight toppling bending of the near-slope rock strata, whereas the toppling bending deformation of the rock strata of the model with a slope angle of 75\({}^{\circ}\) was remarkable. As the toppling deformation of the slope models further developed, the toppling bending degree of the rock strata increased gradually, and the interlayer tension became more conspicuous. Intermittent tensile cracks generated inside the rock mass and the toppling bending intensified towards the free face until the rock strata broke.