The sudden changes of soil properties after shallow landslides were found to aggravate the soil erosion on loess slopes in field and laboratory experiments, but which factor plays a dominant role and its variation under different conditions are still unclear. In this study, a coupled runoff and soil erosion model was applied to distinguish and quantify the contributions of four different changing factors after shallow landslide to fill the weaknesses of field and laboratory studies. The effects of different slope, soil, and shallow landslide properties on the variation of the dominant factor were further analyzed in detail. The results showed that the model can accurately simulate the sediment transport rate before and after shallow landslide. A slight difference between simulation and observation occurs because some residual soil in the lower part of slope in the shallow landslide increase the sediment transport rate in the early stage. In comparison, the decrease of soil erodibility plays a dominant role on soil erosion aggravation after shallow landslide than that of the decrease of soil permeability. Moreover, the impacts of decreasing soil permeability and erodibility can complement and reinforce each other on the soil erosion aggravation. The soil erosion of changing both soil permeability and erodibility after shallow landslide is about 5-200 times larger than that of only changing any one factor. Sensitivity analyses showed that the dominant factor for soil erosion aggravation after shallow landslide  remains unchanged for different slope, soil, and shallow landslide properties. In addition, using a temporal varying erosion coefficient in the model can reflect the impact of residual soil in the lower part of slope and the simulation accords better with the observations. These results are expect to provide a theoretical and quantitative explanation for how shallow landslide affecting following soil erosion on steep loess slopes.

浅层滑坡;水力侵蚀