Abstract: An anchor with a longitudinally folded pipe and with an end piece which can be opened under pressure and which is provided on the end of the anchor lying inside in the drilled hole is introduced into the drilled hole, and by applying internal pressure is expanded as the pipe unfolds until the pipe with frictional locking and/or positive locking adjoins the drilled hole, whereupon the pressure in the anchor is raised so that the forward tip of the end piece is separated. Then the hardening mass is pressed through the anchor into the drilled hole in order to fill cavities in the area of the anchor end located at the bottom of the drilled hole and the substratum (soil, rock) in which the anchor is fixed, and cavities or cracks located in the bordering substratum. A hydraulically binding, cement-based mass can be used especially as the hardening mass.