Abstract: The risk of dam-break flood is uncertain as affected by environment,load and people.The risk of flood disaster is assessed in consideration of the depth and velocity of flood.The propagation of dam-break flood is simulated by using two-dimensional hydrodynamic model with HEC-RAS software and GIS spatial analysis technology,and the exposure of disaster-bearing bodies are analyzed from flood arrival time and inundation range.The vulnerability of disaster-bearing body is analyzed according to the experimental data of human instability and building stability criteria.Finally,the risk analysis method for dam-break flood and the risk rating standard based on the disaster system theory are proposed to assess the risk of dam failure,classify the risk level of population in dam-break flood inundated area,and to provide technical support for planning and preparing the rescue and migration in dam emergency.

Key words: dam-break flood, risk assessment, rating, risk, exposure, vulnerability, building damage