Design and performance verification of fabricated pre-tunnel shading structure in road tunnels

This study investigates the efficacy of pre-tunnel shading structures in mitigating the "black hole effect" at tunnel entrances to reduce traffic accidents. Utilizing modeling techniques, light reduction performance analyses, 3D printing, and artificial sky simulations, data on the daylight factor of a scaled tunnel model under standard overcast sky conditions were obtained. The analysis reveals that shading structures effectively attenuate the rapid decrease in illumination at tunnel entrances, with top-line symmetry gradient shading pattern exhibiting optimal performance. Furthermore, the implementation of shading structures in tunnel entrances yields substantial energy savings, potentially up to 75%. The study concludes by outlining future research directions, including the integration of shading structures with photovoltaic systems and the refinement of structures for tunnels with specific orientations. More shading structure design and application could be developed, offering improved safety and sustainability in tunnel infrastructure.