CUTTING BIT AND METHOD FOR EARTHQUAKE STRENGTHENING EXISTING CONDUIT FIXED TO MANHOLE

摘要

PROBLEM TO BE SOLVED: To provide a cutting bit which allows for increased width of an annular void to be cut without alteration of the thickness of a cylindrical core body, and a method for earthquake strengthening an existing conduit fixed to a manhole.

SOLUTION: A cutting bit comprises a plurality of first cutting blades 6 which are arranged at a prescribed pitch on an edge face 5a in an axial direction of a cylindrical core body 5 and project in the axial direction of the core body 5, and a plurality of second cutting blades 7 which are arranged at a prescribed pitch on an outer peripheral surface 5b of the edge face in the axial direction of the core body 5 provided with the first cutting blades 6 and project in a radial direction of the core body 5.

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