# Evolution Process of Toppling Deformations in Interbedded Anti-Inclined Rock Slopes
## 3 Results
### Evolution of the Slope Velocity  
The velocity vector fields of the slope at specific times were recorded using the PIV method. After 80 s of conveyor belt operation, the deformation rate at the slope shoulder was the highest, with the value of 5.9 \(\times\) 10\({}^{-4}\) m/s. The deformation rate progressively diminished along the direction of the rock layers from the slope surface toward its interior. The surface deformation rate decreased significantly from the shoulder to the toe of the slope (Figure 8a). After 130 s of conveyor belt operation, the peak deformation rate at the slope shoulder reached 19.5 \(\times\) 10\({}^{-4}\) m/s, while the peak deformation rate at the slope crest was 16.7 \(\times\) 10\({}^{-4}\) m/s. Due to the differences in deformation rates between the slope shoulder and crest, significant tensile fractures formed along the rock layer in the middle part of the slope crest (Figure 8b). After 180 s of conveyor belt operation, the deformation rate at the slope shoulder significantly decreased, with a peak rate of 5.8 \(\times\) 10\({}^{-4}\) m/s. The tensile fractures parallel to the rock layer formed at the slope crest provided ample movement space for the rear rock column, resulting in a larger deformation rate at the rear part of the slope, with a peak rate of 7.2 \(\times\) 10\({}^{-4}\) m/s (Figure 8c). Therefore, the accelerated rotation of the free rock columns gradually closed the tensile fractures parallel to the rock layer, causing the lateral surfaces of neighboring rock columns to reestablish contact. Subsequently, the deformation rate of the slope significantly decreased. The peak deformation rate observed in the slope decreased from 14.2 \(\times\) 10\({}^{-4}\) m/s at 230 s to 3.2 \(\times\) 10\({}^{-4}\) m/s at 380 s, and the deformation gradually stabilized (Figure 8d-g). As the toppling fracture zone gradually developed within the slope, the deformation rate of the rock columns above the zone of fracture significantly increased, with a peak value of 12.8 \(\times\) 10\({}^{-4}\) m/s, leading to the ultimate instability of the slope (Figure 8h,i). Figure 9 illustrates the temporal variations of the average velocity for the slope. It can be seen that the average velocity of the slope experienced a significant decrease before 80 s. This is because the initial rotation of rock columns was constrained by the surrounding rock columns. After 80 s, with the gradual formation of the tensile fractures parallel to the rock layer, the interlayer frictional resistance decreases significantly. The slope deformation produced a significant increase and reached its peak deformation rate. Notably, the slope deformation rate exhibited a wide range of oscillatory variations, which may be associated with the incompatible rotation between soft and hard rock columns. After 230 s, as the interlayer tensile fractures completely closed, the interlayer frictional forces were reinstated. Consequently, the slope deformation rate significantly decreased, transitioning  
Figure 7: Horizontal displacement of the monitoring points in the slope model: (**a**) Displacement of b and d series monitoring points; (**b**) Slope surface displacement at different elevations. The location of each monitoring point is presented in Figure 3b. into a phase of creep. After 460 s, a notable increase in deformation rate reemerged, indicating that the ultimate failure of the slope occurred. Due to the limited extent of the ultimate failed rock masses, the average deformation rate during the final failure phase was lower than that observed during the initial rotation phase (before 230 s). Note that the horizontal deformation dominated the initial rotation of the rock columns, while in the failure phase, vertical and horizontal movements were both evident. This is because the final destabilization of the slope exhibited a composite movement pattern that contained downslope overlapping, overturning, and shear sliding (Figure 4i).