| 摘要 |
A rock anchor bolt (18) comprising an elongated rod (10, 12, 14, 16, 18) which is provided over its outer surface with at least one (11), two (13), three, (17) or four (15) axially extending grooves. The rod (10, 12, 14, 16, 18), is preferably twisted over its length and provided over one of its ends (22) with screw threads (23) in order to receive a cooperating nut (25).
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