Abstract: The mechanical principle and failure characteristics of progressive collapse of the shield tunnel are important. Thus, three methods of singlecase analysis, fault tree analysis (FTA), and event tree analysis (ETA) are used to analyze the characteristics of progressive collapse of shield tunnel. The analysis of five major shield tunnel collapse cases in China and abroad show that the failure process of shield tunnel structure has obvious nonproportionality and continuity characteristics, with the nature of the progressive collapse. The FTA results of cases show that the progressive collapse of the shield tunnel is usually due to the leakage of lining structure under specific stratum conditions. Finally, the process of shield tunnel collapse is divided into four events by ETA, and the interaction mechanism between soil erosion and structure in the collapse process of tunnel structure is discussed.

Key words:  , shield tunnel, progressive collapse, case study, fault tree analysis (FTA), event tree analysis (ETA)