SELF DRILLING ROCK BOLT

摘要

A self drilling rock bolt (10) incorporating a shaft (13) and an anchoring device (23). A first end (11) of the bolt has a drill tip (16) to penetrate rock and a second end (12) is adapted to be connected to a drilling apparatus to allow rotation of, and thrust to, the bolt. A circulation passage is provided to allow fluid to be passed to the drill tip (16) and in one form a central passage (14) is formed in the shaft (13) to form part of this circulation passage. The anchoring device (23) is operative to retain the bolt when located in a drilled hole and comprises a mandrel (29) having one or more inclined external surface (29, 30) mounted to, or integrally formed with, the shaft (13) and at least one expansion element (24) overlaying the mandrel. The expansion element(s) (24) is displaced radially outwardly on a predetermined relative movement between the mandrel (29) and the element (24).