PURPOSE: To seal the end of a heavy corrosion-proofing steel sheet pile within a short period of time by putting a heat adhesive bond and a plastic layer on the surface of the steel sheet pile to thermally bind them, and bringing a plastic bar body into contact with the end of a coating layer while high temperature is kept to weld them with conduction heat.
CONSTITUTION: A steel sheet pile 1 applying an organic primer agent 5 and an inorganic agent 4 to the surface thereof is heated over the temperature of a heat adhesive. A plastic layer 2 is made to push and thermally adhere to the surface of an inorganic primer layer 4 of the steel sheet pile through a heat adhesive bond 3 to form a coating layer of the steel sheet pile 1. Then, the plastic sheet 2 and adhesive bond 3 are cut in a position of the arrow B, and excessive plastic sheet 2 and adhesive bond 3 are eliminated. When temperature of the steel sheet pile 1 is over the heat adhesive temperature, a plastic bar body 8 is brought into contact with the end 2' of the plastic layer, and they are thermally welded. By this constitution, on-line processing is feasible, and processing time is reduced. Since there is no bubble mixture in a seal section, sufficient adhesion strength is obtained.
NOGUCHI AKINOBU
HASHIZUME YOSHIO
