PURPOSE: To prevent the leakage of water by a method in which a synthetic resin cylinder having a projected spacer on its peripheral side is folded and inserted into a manhole, the inside of the cylinder is restored to its original form by heating and pressurizing, and a filler is packed into the space between the manhole and the cylinder.
CONSTITUTION: A thermoplastic rigid plastic cylindrical container having many anchoring projections 12 on its peripheral side is formed as a waterproofing material 1. The peripheral side of the container 1 is covered with a non- expandible cylindrical net for preventing overmuch expansion. The waterproofing material 1 is softened by heating, folded to a reduced outside diameter, and inserted into manhole (a). The opening of the material 1 is closed with a stopper 2, and the inside of the material 1 is expanded by heating and pressurizing to restore it to its original form and hardened. A back filler 6 such as cement milk is packed into the space 5 between the manhole (a) and the material 1. The formation of space on the back of the material 1 can thus be prevented and the preventing effect against water leakage can be kept for long periods.
KAMIIDE AKIRA
UGA RYOTA
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