Tokyo Bay Aqua-Line/Undersea tunnel ventilation system (Japan)

The Tokyo Bay Trans-Japan Highway (Tokyo Bay Aqua-Line), which opened in 1997, is approximately 15 km long and connects Chiba and Kanagawa prefectures. The Aqua Tunnel, which crosses the seabed of Tokyo Bay, occupies approximately 10 km of this expressway. It is the longest underwater tunnel in the world and is equipped with EBARA ventilation systems. In road tunnels, natural ventilation is provided by natural wind caused by the pressure difference between the two shaft openings and by the flow generated by the piston action of traveling vehicles. In road tunnels where natural ventilation alone is not enough to cope with the situation, such as when the required ventilation volume increases due to an increase in traffic volume, mechanical ventilation is carried out by installing ventilation equipment.

For disaster prevention reasons, the Tokyo Bay Aqua-Tunnel has a special structure in which the tunnel cross-section is divided into two levels, upper and lower, by the deck, and the tunnel diameter is 14m. Utilizing the ventilation power of traffic, a low-cost, energy-saving ventilation system was employed, and we developed two exhaust fans with a diameter of 4 m, two fans under the floor slab, and their auxiliary systems.The Tokyo Bay Aqua-Line has brought many benefits, including easing traffic congestion in the city center and improving industrial activity.We are committed to provide safe driving environment. The Tokyo Bay Aqua-Line has brought about various benefits, including easing traffic congestion in the city center and increasing industrial activity. We will continue to provide an environment where many people can ride safely.