Mitigating Fatigue in Tunnel Construction through Illumination: Evidence from Virtual Reality

Abstract

Tunnel construction is crucial to the advancement of global transportation networks. Despite their importance, there have been few investigations on the safety and comfort of workers. Tunnel workers operate under various adverse conditions that lead to multiple forms of fatigue. Researchers have suggested that there is a specific type of fatigue stemming from insufficient natural or improper artificial lighting that has largely been overlooked in previous studies. To validate the existence of illumination-induced fatigue and explore control measures, this study conducted virtual reality experiments in a simulated tunnel construction setting and collected and analyzed data from scales, electroencephalogram, and eye-tracking. The results indicated significant variations in fatigue levels with changes in illumination, whereas the environment remained constant, confirming the presence of illumination fatigue. Moreover, the analysis of the scale results aligned with the EEG findings, ranking the comfort levels of the mucking illumination as 100>75>150>50>200>30>15>10>0 lx. The modeling of illumination fatigue identified three comfort levels of illumination, I: [75, 100], II: [15, 75) ∪ (100, 200], III: [0, 15], thereby establishing that illumination fatigue can be controlled through improved lighting. Subsequently, to address the issue of uneven illumination distribution at construction sites, key areas for mucking task lighting were identified using eye-tracking technology as the upper and lower edges of the bucket, debris being moved, and expected stacking area. Finally, by comparing and summarizing the divergent conclusions of previous studies, this study proposed various targeted lighting guidelines. This comprehensive study not only enriches the current understanding and experimental design reference for tunnel construction fatigue but also provides practitioners with specific and effective lighting guidance to significantly reduce workers’ fatigue and improve their working conditions. The results of laboratory studies indicate that inadequate or excessive artificial lighting during tunnel construction significantly increases worker fatigue. This research identified an illuminance range of 75–100 lx as the most comfortable range for mucking activities. Occasionally, the construction environment is complex, making it challenging to control the illuminance distribution uniformly. Therefore, this study further examines the attention distribution during the mucking processes, identifying key lighting points as the upper and lower edges of the bucket, debris being moved, and expected stacking area. Furthermore, the results of this study address the discrepancies in previous guidelines on illumination levels and propose different illumination ranges tailored to specific construction areas. Worldwide construction teams can determine the appropriate level of illumination within these ranges by considering the composition of the workforce, environmental factors, and policy requirements. These findings can help enhance worker comfort and improve construction safety, ultimately ensuring productivity and efficiency.