Abstract: The study of the mechanism of metro tunnel collapse accident and the strengthening of construction risk prevention and the risk control of key links and processes in metro tunnel construction are of great significance. Hence, the causes and types of collapse accidents in current urban rail transit tunnel construction are analyzed; recognition of the formation mechanism of metro tunnel construction collapse is further deepened; it is pointed out that the prevention of accidents must be guided by safety production laws and regulations and construction safety standards; a dual prevention mechanism of risk control and hidden danger investigation is established; the direct causes and existing problems of shield tunnel accidents is analyzed in depth with specific cases; and the causes and violations of the accidents are explored. On the basis of the analysis of irregularities and responsibilityseeking behavior, the preventive measures for metro tunnel collapse accidents are provided from the aspects of improving the safety responsibility system of the metro construction based on the principle of safety production management, further improving and perfecting the safety regulations and technical standards system of metro construction, establishing the safety risk management system of metro construction by grading and classifying, speeding up the deep integration of information technology and safety production, etc.

Key words: metro tunnel, collapse accident, control countermeasures, risk control, risk investigation