# Evolution Process of Toppling Deformations in Interbedded Anti-Inclined Rock Slopes
## 3 Results
### Evolution of the Slope Displacement  
The contours of displacement of the slope at specific times were recorded using the DIC method. After 80 s of conveyor belt operation, the slope underwent overall deformation. The contour lines of horizontal displacement extended nearly perpendicular to the rock layers. The displacement decreased with increasing burial depth, indicating the continuous bending deformation of the rock column. The maximum horizontal displace  
Figure 4: Deformation and failure process of the slope model (**a**–**i**) are the 80 s, 130 s, 180 s, 230 s, 285 s, 335 s, 380 s, 475 s and 490 s after the operation of the conveyor belt). ment at the shoulder of the slope was 50.3 mm (Figure 5a). As the conveyor belt operated, the horizontal displacement showed distinct differentiation on both sides of the tensile fractures parallel to the rock layer at the slope crest. The maximum observed deformation still occurred at the slope shoulder, which reached 196.0 mm after 180 s of conveyor belt operation (Figure 5b,c). Subsequently, the tensile fractures parallel to the rock layer gradually closed, and the heterogeneity of slope deformation disappeared. The contour lines reverted to parallel distribution characteristics, and the maximum horizontal deformation still concentrated at the slope shoulder. Note that from 230 s to 380 s, the horizontal displacement at the slope shoulder increased from 254.2 mm to 270.0 mm. In other words, the rate of deformation decreased significantly during this period, indicating a creep deformation stage (Figure 5d-g). After 490 s of conveyor belt operation, the horizontal displacement at the slope shoulder surged to 341.7 mm, while the maximum horizontal displacement at the rear part of the slope crest remained approximately at 240.0 mm from 475 s to 490 s (Figure 5h,i). This indicated that the unstable rock masses separated from the deformation body and the ultimate instability of the slope occurred. The contour maps of slope vertical displacement exhibit similar features to those of slope horizontal displacement (Figure 6). The maximum vertical displacement was also located at the slope shoulder. However, the magnitude of deformation was notably less than the horizontal displacement at the corresponding instant. From 230 s to 380 s, the peak value of the slope vertical displacement increased from 140.8 mm to 156.4 mm. After 490 s of conveyor belt operation, the vertical displacement at the slope shoulder surged to 202.3 mm. Figure 5: Horizontal displacement contour map of the slope model (**a–i**) are the 80 s, 130 s, 180 s, 230 s, 285 s, 335 s, 380 s, 475 s and 490 s after the operation of the conveyor belt, unit: mm). Although the entire model was included in the DIC analysis, no significant displacements were observed at the lower and left sides of the slope model, which was consistent with the macro deformation characteristics of the model (Figure 4). This indicated that there is no boundary effect in the test. The displacement contours of the slope model obtained from DIC analysis were accurate and reliable. Nine characteristic points were selected to record the variations of displacements at different locations (Figure 3b). Overall, the displacement at each monitoring point experienced three evolutionary stages: the initial increase, subsequent stabilization, and final surge, which corresponded to the initial rotation, intermediate creep, and final instability of the slope, respectively. As shown in Figure 7a, the horizontal deformation gradually decreases along the rock layer from the surface to the interior. When considering the same burial depth along the layer direction, the deformation of rock masses in the upper slope is greater than those in the lower slope. Rock masses located above the toppling fracture zone eventually produce a surge in deformation (points b-1, b-2, d-1 and d-2), while rock masses below the THS exhibit minimal deformation (point d-3).