PURPOSE: To inhibit the movement of a large quantity of underground water in the ground and prevent the liquefaction of the ground by driving a drainage mechanism, sucking underground water by a drain pipe and draining flowing underground water onto the ground by a drainage path when an earthquake has happened.
CONSTITUTION: When a seismoscope 22 is mounted and the initial shock waves of an earthquake are sensed, a valve gear installed between a vacuum tank 23 and a manifold 25 is opened on the basis of the earthquake sensing signal of the seismoscope 22. Underground water is sucked by each drain pipe 20, underground water flows in the ground 17 and flowing underground water is drained to an underground section by gravel piles 21, and the movement of a large quantity of underground water into a liquefaction preventive ground 18 is inhibited. Accordingly, the increase of excess void water pressure at the time of the earthquake of the liquefaction preventive ground 18 can be obviated by the suction of underground water by the drain pipes 20 and the discharge of underground water by the gravel piles 21.
ISHIKAWA YUTAKA
KOSAKA NOBUAKI
SATO MASAYOSHI
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