The Impact of the Tunnel Micro-Environment on Workers' Behavior: Considering the Mediating Role of Mental Health

Against the backdrop of accelerated global infrastructure development, one of the key objectives of sustainable development is to achieve a construction model that is safe, efficient, and environmentally low-impact. Therefore, the safety of tunnel construction and the health of workers have become central issues in sustainable development. The present study explores the relationship between the tunnel micro-environment and unsafe behavior of construction workers, with a focus on the mediating role of mental health. The study collected construction micro-environment data, basic information of construction workers, mental health status, and data on unsafe behavior from six tunnels as research samples. The tunnel micro-environment was primarily tested for noise and dust concentration. Noise data were obtained through on-site measurements, while dust concentrations were obtained from both field measurements and Fluent numerical simulations. The findings of the research indicate that noise and dust concentration in the tunnel micro-environment have a significant impact on the mental health and unsafe behavior of construction workers (p < 0.001). Based on structural equation modelling, we found that the stress, emotional regulation ability, and physical health statuses of tunnel construction workers had a significant impact on their mental health. Behaviors such as ignoring warning signs and working in high-risk areas had the most significant impact on unsafe behavior, with standardized path coefficients greater than 0.75. Concurrently, mental health status played a significant mediating role between the tunnel micro-environment and unsafe behavior. Finally, the study determined the environmental threshold values for noise and dust concentration at varying risk levels. This finding is of significant value in the reduction in occupational disease risks, the enhancement of the livability of work environments, and the provision of scientific evidence for the long-term sustainable development of infrastructure construction.