Renovation of Kiyotsu Gorge Tunnel—A Case Study on the Effect of the Combination of Visual Information and Environmental Grade in a Sequential Space on Human Psychological Response

Abstract

This project is based on the hypothesis that the combination of visual information and environmental grades—such as airflow and temperature—in a uniform, sequential space can influence psychological responses. To explore this hypothesis, we selected the Kiyotsu Gorge Tunnel as a case study. This tunnel provides a controlled spatial environment with limited external visual stimuli and includes four viewing decks that open to the outside, allowing natural light, air, and temperature variation to enter the interior. The renovation was intended to couple visual stimuli with airflow variation, under the hypothesis that this co-variation may strengthen psychological responses. Architectural elements, including water ponds and reflective mirrors, were introduced to enhance airflow or reflection from the exterior and intensify sensory engagement. Through this combination of visual and environmental cues, the project sought to create a cohesive, immersive experience throughout the entire tunnel.