To provide a means for preventing the leakage/percolation of water from/into a storage tank which forms a storage space using a lightweight member.
A space, which is secured by assembling or arranging members underground, serves as the storage space by being covered with an impervious sheet. The storage tank is constituted by covering the bottom surface and peripheral side surface of the storage space with the impervious sheet. The storage tank is reinforced by covering the bottom surface and peripheral side surface of the storage tank with an iron plate. In the reinforced storage tank, a sand layer is provided between the iron plate and the impervious sheet covering the bottom surface. The bottom surface and the peripheral side surface are covered with the iron plate so as to prevent the impervious sheet from being damaged by a buried object such as crushed stones and a root of a tree. The sand layer is provided between the bottom impervious sheet and the iron plate so as to prevent the impervious sheet from being damaged by the reinforcing iron plate.
HAYASHI KAZUSHIRO
HAYASHI KOZABURO
HAYASHI KANAKO
