Abstract: In a rock anchor bolt a centering member includes an outlet hole for removing any leakage water flowing into a borehole. The rock anchor bolt includes a sealing device provided around the outer end of a tube to seal the borehole watertight as a tightening nut is being tightened, and an outlet tube provided in a casting space between the tube and a drawbar to carry out the leakage water as grouting paste is being injected, the inner end of which outlet tube extends to the vicinity of an expansion member and the outer end of the outlet tube extends out from the outlet hole of the centering member. The tube has one or more first casting holes at the outer end of the tube in the vicinity of the sealing device and one or more second casting holes at the inner end of the tube near the expansion member.

Abstract: In a rock anchor bolt a centering member includes an outlet hole for removing any leakage water flowing into a borehole. The rock anchor bolt includes a sealing device provided around the outer end of a tube to seal the borehole watertight as a tightening nut is being tightened, and an outlet tube provided in a casting space between the tube and a drawbar to carry out the leakage water as grouting paste is being injected, the inner end of which outlet tube extends to the vicinity of an expansion member and the outer end of the outlet tube extends out from the outlet hole of the centering member. The tube has one or more first casting holes at the outer end of the tube in the vicinity of the sealing device and one or more second casting holes at the inner end of the tube near the expansion member.

Abstract: A rock bolt to be installed into a borehole (1) drilled in a rock is described. The rock bolt includes wherein an expansion member (9) of the rock bolt includes an internal second cone abutment surface (12) in the interior of the expansion member in the vicinity of a second end thereof. A second cone member is at least partially fitted in the interior of the second end of the expansion member. The second cone member includes a hole (14), through which a drawbar is adapted to extend with a clearance, and a second cone surface (15) tapering inward relative to the expansion member and abutting against the second cone abutment surface (12) of the expansion member.

Abstract: The invention relates to a rock bolt to be installed into a borehole (1) drilled in a rock, wherein an expansion member (9) of the rock bolt includes an internal second cone abutment surface (12) in the interior of the expansion member in the vicinity of a second end (10) thereof. A second cone member (13) is at least partially fitted in the interior of the second end (10) of the expansion member (8). The second cone member includes a hole (14), through which a drawbar (2) is adapted to extend with a clearance, and a second cone surface (15) tapering inward relative to the expansion member and abutting against the second cone abutment surface (12) of the expansion member.