WATER SEALED UNDERGROUND TANK

PROBLEM TO BE SOLVED: To prevent air from leaking from a cavity into the surrounding baserock when water is led from the cavity formed in the underground baserock into the surrounding baserock so as to eliminate an unsaturated state of the baserock certainly. SOLUTION: In a water sealed underground tank, the cavity 1 without lining work is drilled in the underground baserock, and a storage fluid is sealed in the cavity 1 under underground water pressure in the baserock surrounding the cavity 1. An air accumulating part 3 is secured at the top of the cavity 1, where an exhaust pipe 6 for exhausting air from the air accumulating part 3 is also provided. The cavity 1 is tunneled so that the entire cavity 1 or only the top end face of the cavity 1 becomes upwardly sloped, and the air accumulating part is secured at the top of the cavity 1 on the top end thereof, where the exhaust pipe 6 is provided. An access pit 4 is connected to the air accumulating part 3 or to any given spot on the cavity 1, and a plug 5 is mounted on the connection of the access pit 4, then the exhaust pipe 6 is made to penetrate the plug 5 directly, or after being laterally extended, from the air accumulating part 3. COPYRIGHT: (C)2005,JPO&NCIPI