ROCK BOLT

PROBLEM TO BE SOLVED: To make a threaded portion of an FRP rock bolt equal to a threaded portion of a metal rock bolt by screwing a metal pipe-shaped member to a base portion of an FRP rock bolt formed with a rope-shaped thread on the outer periphery. SOLUTION: A metal pipe-shaped member 52 is screwed thereby forming a threaded portion at a base portion of the main body portion 51 of an FRP rock bolt made by solidifying a bundle of strengthened fibers such as glass fibers with a thermosetting resin. For the main portion 51, a rope shaped threaded portion 51a is formed on the outer peripheral surface, its tip portion is made to a blade tip, and a pipe-shaped member 52 is formed to an internal thread 52a on inner peripheral surface screwing to the main body portion, and an antirotation groove is formed together with an external thread 52b on the outer peripheral surface. And a hole is drilled from an internal wall of the tunnel excavated in the natural ground to the inner portion of base rock, an fixing agent is injected, FRP rock bolts 51, 52 are driven, a nut 54 is screwed through a square washer 53 to the pipe shaped member 52 and tightened and anchored. Thus, the threaded portion of the FRP rock bolts 51, 52 can be made identical to that of a metal rock bolt.