RESEARCH ACTUALITY AND EVOLUTION MECHANISM OF POST-FIRE DEBRIS FLOW

The post-fire debris flow is another special type of debris flows that closely related to forest fire and generate in burned area. Obvious difference in term of the initiation mechanism has been find between post-fire debris flows and general debris flows. Fire combusts the surface vegetation and furtherly destroys the texture of underlying soil for the high temperature of fire. The unit weight, pore porosity, permeability and other physical and hydrological properties of the fire-infected soil are changed dramatically in fire, and abundant residual ash layer and loose debris accumulated on the slope after fire. Therefore, post-fire debris flows usually have the characteristics of high unit weight and viscosity. A review of research on the generation mode, kinetic mechanism, influence factors, debris flow forecasting and mitigation measures of this kind of debris flows is put forward, referring to relevant literature at home and abroad. Post-fire debris flows are first studied in 1936, detailed study on which is mostly conducted in America, Australian and Spain. But few can been find in China, except the researches in agroforestry, in which the study are mainly about water and soil loss, vegetation combust and recovery. As another special type of debris flow hazards, systematic study of post-fire debris flows has not attracted enough attention in China, which reflects the poor study of this kind of debris flows. Based on the key problem mentioned above, some suggestions are came up with to enhance the research on the generation and spatial-temporal evolution mechanism and effective protection of post-fire debris flows.