Abstract: A rock bolt is provided for insertion into a bore in the roof or side wall of an underground opening so as to stabilize the roof or wall of the opening. The rock bolt comprises a generally hollow elongate body having a side wall wherein the side wall has a flute formed from a pair of inwardly disposed wall portions interconnected at their respective inboard ends to form a hinge. The hinge is responsive to forces applied to and along the side wall by the bore so that the rock bolt may be deformed in the bore to accommodate stresses and strains placed upon the bolt during use without substantially weakening the strength of the bolt held in the bore.