Abstract: To study the deformation and failure characteristics of the slope of gently inclined accumulation layer caused by intermittent rainfall, taking the Yingtaogou landslide as an example, a physical simulation study on the slope deformation and failure under the action of rainfall was carried out. The results showed that under the action of early rainfall, the deformation characteristics of the slope body showed the sliding and subsidence at the leading edge, the sliding in the middle part, the subsidence at the rear edge, and the formation of slope cracks and the obvious expansion of leading-edge cracks. Under the action of late rainfall, the slope foot area was the first to slide, and then the sliding was transferred to the trailing edge resulting in progressive sliding failure. Rainfall infiltration was easy to store on the bedrock surface, forming transient groundwater level, high pore water pressure area and slope seepage field. The soil near the bedrock surface was saturated with water for a long time, so it had a high degree of softening, and a significant weakening in shear strength, causing the slope prone to landslide along the soil layer at the base interface. Slope sliding tended to occur during the rainfall intermittent period. The triggering characteristic of slope sliding were as follows: after rain, the continuous infiltration of the water in the transient saturated area of slope body and the accumulated water on the slope surface led to the rise of the groundwater level lagging behind the rainfall, causing the increase of buoyancy in the slope, permeability and pore water pressure, so that the effective stress in the slope body decreased, which induced the landslide.

Key words: intermittent rainfall, slope of gently inclined accumulation layer, physical simulation, deformation