Electrolytic corrosion prevention method of underground metal pipe, as well as, electrolytic corrosion prevention structure

摘要

PURPOSE:To prevent the galvanic corrosion of an underground metallic pipe with simple works by setting a sacrificial anode material in the soil close to the pipe, connecting the anode material to the pipe through a lead wire, and covering the material with the backfill. CONSTITUTION:The pavement is bored by a drill A to make a small hole 2 leading to the metallic pipe 1. The pipe 1 is grinded, and a lead wire 3 is connected to the pipe 1. An injection pipe 4 having a drill bit 4a and a sacrificial anode material 4b is inserted obliquely to the pipe from the small hole 2 on the surface side. An injector C is connected to the injection pipe 4. The fluid backfill 5 is supplied from the injector C under pressure, and injected into the soil from the holes of the anode material 4b to form the backfill covering the anode material 4b. The injector C and a part of the injection pipe 4 are then recovered. The lead wire 3 is inserted into the inclined small hole 6, and connected to the anode material 4b. The small hole 2 and the inclined small hole 6 are finally backfilled to bury the lead wire 3, and the bored part of the pavement is repaired.