Abstract:Under natural conditions, rainfall mostly occurs intermittently, and slope soil erosion is a gradual and complex process. Through 15 indoor simulated rainfall experiments, including three rain intensities (60, 90, 120 mm/h) and five slopes (5°, 10°, 15°, 20°, 25°), the runoff and erosion process were studied under the conditions of primary and secondary rainfall. The slope erosion development process and the changes of main influencing factors under intermittent rainfall conditions were discussed. The results showed that: (1) The runoff time of the second rainfall was earlier than that of the first rainfall. The total runoff of the first rainfall was affected by rain intensity, slope, and rainfall. The slope of 15° was a turning point for the change of the total runoff. The effect of rainfall was weakened during a single rainfall, the maximum difference multiple under each rainfall intensity was reduced, and the multiple gap between the slopes was also reduced. (2) The main driving force for rill erosion in a single rainfall was the rainfall intensity. Rill erosion was more likely to occur in the case of steep slopes, and the 15° slope was of great significance to the generation of rill erosion. At this time, if rill erosion occurred, the slope erosion was mostly dominated by rill erosion, and both erosion showed a positive proportional function relationship. The amount of rill erosion caused by the secondary rainfall was related to the development of the rill during the primary rainfall. The more intense the rill development of the primary rainfall, the less the amount of rill erosion caused by the secondary rainfall. The amount of rill erosion had a linear function relationship with the total erosion amount. In general, the change in the total erosion amount was closely related to the stage of rill development. (3) Under intermittent rainfall conditions, there were differences in the influences of different rainfall intensity, slope, and rainfall on the slope soil runoff. At the same time, the change of soil runoff and erosion in the primary rainfall had an important impact on the development of secondary rainfall runoff and erosion in the later period, so that at different stages of soil erosion development, the influencing extent of rain intensity, slope, rainfall and other factors on the slope soil runoff and erosion also changed accordingly.