事務所の取り組み
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首都圏外郭放水路
Overview of Facilities
Pressure-Adjusting Water Tank
This is a facility that ensures the smooth flow of water to the Edogawa River by reducing the momentum of the water from the underground tunnel.
This massive water tank serves two purposes: reducing the momentum of water through stable pump operation and regulating the backflow of water, which occurs when the pump’s emergency brakes are activated. It is located 22 meters below the ground, with a length of 177 meters, a width of 78 meters, and a height of 18 meters. The area directly above the Pressure-Adjusting Water Tank is a soccer field, so you can imagine its size even from ground level. With an impressive interior, massive pillars, and vast open space, it has also been referred to as the “Underground Shrine,” serving as a popular structure that symbolizes the Metropolitan Outer Area Underground Discharge Channel.
Pillars
Each of the pillars supporting the ceiling of the Pressure-Adjusting Water Tank is seven meters deep, two meters wide, 18 meters tall, and weighs approximately 500 tons. All 59 pillars standing up right makes for a stunning sight. So, why are there so many huge pillars set up here anyway? Because the Pressure-Adjusting Water Tank was built on land with a high groundwater level, there is a risk of the tank rising due to pressure from the groundwater beneath it. Using pillars to support to the ceiling suppresses the buoyancy from underground, preventing the Pressure-Adjusting Water Tank from rising.
Ceiling
It is necessary to weigh down the Pressure-Adjusting Water Tank in order to prevent it from floating upward due to pressure from the groundwater beneath it The tank is therefore supported with sand and concrete beams on the ceiling in addition to the weight of the concrete in both the pillars and the floor. The area above the ceiling is used as a multi-purpose sports ground, at the request of the local community.
Multi-Purpose Space (Soccer Field, Skateboard Park )
Soccer Field
Skateboard ParkThe aboveground portion of the Pressure-Adjusting Water Tank is a multi-purpose space managed by the local Kasukabe city government, by the requests from the local community. The section located directly above the Pressure-Adjusting Water Tank serves as a soccer stadium, and the section above the No.1 Bank is a skateboard park.
Local residents can use the space freely and events are held there. It serves as a place for social interaction among community members as well as a spot for rest and relaxation.