Bochumer Eisenhutte Heintzmann & Company

Bernhard Stephan

Manfred Koppers

Karlheinz Bohnes

A rock anchoring arrangement for use especially in tunnel and mine constructions involving considerable convergences comprises an anchoring sleeve having a leading and a trailing end as considered in the direction of introduction of the anchoring arrangement into an anchoring bore in the rock formation, an anchoring rod having a trailing end portion passing through the interior of the anchoring sleeve and a leading end portion which extends beyond the leading end of the sleeve, a mounting plate arranged at the trailing end of the sleeve and engaging the rock formation around the open end of the bore, and a drawing die secured to the sleeve at the leading end. The anchoring sleeve and the anchoring rod are both retained in the bore by a body of a hardenable material, such as an adhesive, in which the sleeve and the leading end portion of the rod are embedded. The leading end portion of the rod has a smaller diameter than the trailing end portion so that a transition region exists between these portions. The drawing die has an aperture which receives the leading end portion and, when pulling force acts on the arrangement, acts on the transition region to deform the same when the magnitude of the pulling force is at a predetermined level and thus to increase the axial length of the anchoring rod. The aperture is either conical throughout, or includes alternating conical and cylindrical zones.

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Gelsenkirchen, Germany

Bernhard Stephan