Safety risk assessment model of a subway tunnel collapse system based on improved DOW-FFTA method

Green construction considers factors such as quality, safety, efficiency, environmental protection and ecology. Under the premise of balancing basic construction capacity and green construction, prioritizing construction safety requirements and exploring the risk assessment system for the green construction of subway projects is crucial. Traditional risk assessment methods in the study of local system risks have been mostly applied to simple systems; thus, risk identification and assessment methods lack universality. The questions of how to change the existing structure of the system safety risk assessment model and establish a realistic modeling approach, as well as implement dynamic risk supervision, have become urgent problems. Here, we investigated the event risk point and proposed an integrated evaluation method of inherent, initial and real risks based on system attributes. The improved DOW chemical method was used to solve the static inherent risk severity index, and fuzzy fault tree analysis (FFTA) was used to judge the probability of out-of-control local state management. Considering the abnormal situation and the emergence of new risk information, a dynamic correction model was proposed. Finally, a static risk assessment model was established in line with the actual state of the system with local management and realistic risk assessment models that could modify the initial risk over time.