## 4 Slope Stability Analysis and Discussion
### Effect of Wetting-Drying Cycles on Slope Stability  
The judgment of the location and shape of the landslide on the slope is an important method to analyze the stability of the slope, and the reasonable determination of the location and shape of the sliding surface is an important issue in carrying out the stability analysis of the slope. Geotechnical body damage occurs because the shear stress on a certain side reaches the shear strength of the geotechnical body, so it can be analyzed by analyzing the distribution law of the maximum shear strain of the slope to respond to the potential damage area of the slope damage. The distribution of the maximum shear strain increment of the slope under different numbers of rainfall cycles is shown in Figure 7. In Figure 7, the red area represents the maximum value of the slope's maximum shear strain increment and the blue area represents the minimum value. It can be seen that the distribution range of the maximum shear strain increment of the slope before and after the wetting-drying cycles changed significantly. When there was no rainfall, the distribution range of the maximum shear strain increment of the slope was  
Figure 7: Slope maximum shear strain increment under wetting\(-\)drying cycles. (**a**). Slope maximum shear strain increment under 0 wetting\(-\)drying cycle. (**b**). Slope maximum shear strain increment under 1 wetting\(-\)drying cycle. (**c**). Slope maximum shear strain increment under 2 wetting\(-\)drying cycles. (**d**). Slope maximum shear strain increment under 3 wetting\(-\)drying cycles. (**e**). Slope maximum shear strain increment under 4 wetting\(-\)drying cycles. (**f**). Slope maximum shear strain increment under 5 wetting\(-\)drying cycles. larger, showing a circular landslide pattern. In the first wetting-drying cycle, the peak in the maximum shear strain increment of the slope was located on the surface of the slope step, but it was still partially distributed within the slope. When the wetting-drying cycles were further carried out, with the weakening of the physical and mechanical strength of the rock body and the combined effect of water, the distribution range of the maximum shear strain increment of the slope was no longer changed, and all of them were located on the surface of the slope, reflecting the damage pattern of single-bench collapse. The slope factor of safety can most directly reflect the stability of the slope, and the slope factor of safety under different numbers of wetting-drying cycles is shown in Table 3.  
Comparing the slope factor of safety before and after the wetting-drying cycles, it can be seen that it decreases with the wetting-drying cycles. Compared with the non-rainfall condition, the slope factor of safety decreases by about 14 percent in the first wetting-drying cycle, which is mainly caused by two factors: rainfall infiltration and the wetting-drying cycles. The first is the effect of rainfall; the geotechnical body of the slope will reduce the matrix suction under rainfall infiltration, which will reduce the shear strength of the geotechnical body. This will be manifested as a reduction in the resistance to slip force of the slope under the influence of gravity and other factors. The slip force decreases. On the other hand, the infiltration of rainwater will also increase the bulk weight of the geotechnical body, which will increase the downward force of the slope and easily cause landslides. In the process of wetting-drying cycles, the physical and mechanical parameters of the shallow rock mass subjected to wetting-drying cycles will be reduced, and the slope resistance will be reduced, thus decreasing the slope factor of safety. The slope factor of safety decreases with the number of wetting-drying cycles, and the rate of decrease decreases with the increase in the number of wetting-drying cycles.