Safety Risk Evaluation of Metro Shield Construction When Undercrossing a Bridge

The government of China has planned numerous metro projects, and with more metros, undercrossing of bridges can hardly be avoided. Metro shield construction when undercrossing a bridge (MSCUB) frequently takes place in complicated natural and social contexts, which often makes the construction process more susceptible to safety accidents. Therefore, it is crucial to look into the safety risk during MSCUB. This paper identified the safety risk factors during MSCUB by using a literature review and expert group evaluation, proposed a novel safety risk assessment model by integrating confirmatory factor analysis (CFA) and fuzzy evidence reasoning (FER), and then selected a project case to test the validity of the suggested model. The study results show that (a) a safety risk factor list for MSCUB was identified, including four first-level safety risk factors and thirty-seven second-level safety risk factors; (b) the proposed safety risk assessment model can be used to measure the risk values of the overall safety risk of a worksite, the first-level safety risk factors, and the second-level safety risk factors during MSCUB; (c) environment-type safety risk factors and personnel-type safety risk factors have higher risk values during shield construction when undercrossing a bridge; (d) when compared with worker-type safety risk factors, manager-type safety risk factors are the higher risks. This study can enrich the theoretical knowledge of MSCUB safety risk assessment and provide references for safety managers for conducting scientific and effective safety management on a construction site when constructing metro shields undercrossing a bridge.