## 5 Test Data Analysis
### Analysis of Displacement Data  
The differential displacement sensors were installed at the front edge (LVDT3), at the middle (LVDT2), and at the trailing edge (LVDT1) of the test models to monitor the vertical displacements in different zones. The vertical displacement-centrifugal acceleration curves for the monitoring points of the three slope models are shown in Figure 8. The displacement evolution characteristics of these slope models could be analysed in combination with the test phenomena. With the start of the test, the vertical displacement curve of LVDT1, located at the trailing edge, showed linear rapid growth when the centrifugal acceleration increased to 40\(\times\)_g_; however, the vertical displacement fluctuated slightly with time. This indicated that the settlement deformation of the slope models mainly occurred in the early stage of the test; the vertical displacement curve of LVDT2 grew relatively slowly. The vertical displacement slightly lagged behind the loading of the centrifugal force and the settlement deformation of the trailing edge, and the cumulative displacement value was only approximately half the  
Figure 8: Variation curves for the vertical displacements of the monitoring points, (**a**) LVDT1, (**b**) LVDT2, (**c**) LVDT3. value of LVDT1. This is mostly because the monitoring point was located in the transition area between the toppling zone and the un-toppling zone of the slope, which was less affected by the toppling and the settlement deformation. LVDT3 was located in the toppling zone. The vertical displacement curve of LVDT3 grew slowly at first, but the rock mass of the slope generated toppling-bending deformation, and the vertical displacement curve had a corresponding sudden mutation after a period of centrifugal loading. Then, the displacement tended to be stable with the convergence of the deformation. In general, the displacement changes of each monitoring point were basically synchronized with the loading of the centrifugal acceleration and showed step-like growth. The cumulative displacement of each monitoring point is shown in Table 2. The vertical displacement of different parts of the same slope models presented the order trailing edge \(>\) front edge \(>\) middle, indicating that the settlement deformation of the trailing edge was more intense than that of the front edge. Additionally, the vertical displacement value of the same monitoring point shows an upward trend as the slope becomes steeper. This is because the toppling deformation of the slope gradually increases and provides increasing space for vertical deformation. Further analysis of the LVDT3 located near the free face of the slope shows that the vertical displacement curve could intuitively reflect the difference in the toppling deformation with different slope angles. The growth of the vertical displacement slightly lagged behind the centrifugal loading, and this was more obvious when the slope angle was lower (Figure 9a). In the phase of 0-40\(\times\)\(g\) centrifugal acceleration, the vertical displacement curve of the model with a slope angle of 75\({}^{\circ}\) increased rapidly. When the centrifugal acceleration increased to 20 g, the vertical displacement exhibited a 5 mm mutation. Combined with the test phenomena, we found that the rock mass at the slope foot broke and the rock strata toppled and bent. When the centrifugal acceleration increased to 33\(\times\)\(g\), the first-level toppling-bending zone inside the slope penetrated, and the vertical displacement underwent 16 mm mutation. The slope experienced toppling-bending deformation; that of 65\({}^{\circ}\) was gentle first and then steep. When the centrifugal acceleration increased to 25\(\times\)\(g\), the vertical displacement had a 6 mm mutation, indicating that the slope entered the stage of accelerated deformation; that of 55\({}^{\circ}\) had a low deformation rate in this stage, and the vertical displacement exhibited no mutations.