Abstract: An arcuate or circular profile element of generally V-shaped cross-section has a curved bottom wall, arcuate sidewalls having free edges, and laterally projecting flanges projecting from the free edges. By choosing specific relationships between the thickness of the different parts of the element, lighter-weight elements can be used to withstand the same loads as before, or elements having the same weight as before can be used to support heavier loads.

Abstract: A method for removing resilient gallery lining frames in mining and tunnelling, such frames consisting of a number of mutually overlapping lining section segments with a box-like profile, comprises releasing the overlapping section segments from one another in order to recover the respective lining frames. The profile of the section segments has a longitudinal gap and overlapping ends of the segments are braced one with another by a wedge system acting on the longitudinal gap of the inner section, the segments being inserted one within the other in a dissimilar manner. At an overlapping region the outer section segment is bent outwardly to provide an opening at the longitudinal gap therein and the inserted end of the inner section segment at the overlap is moved substantially normal to the opening made by the outward bending to release the overlapping sections from one another.

Abstract: A method for lining chambers and galleries, especially mining and tunnelling galleries, employs resilient steel supporting frames which consist of a number of box-like section segments capable of being slid one into another and which thus, at least in the zone of overlap, constitute a closed tube. The ends of the overlapping segments are widened or compressed, as the case may be, and then inserted one into another. Each overlapping outer section segment is then mechanically compressed in the region of the overlap until ears of the so compressed segment grip behind flanges of the overlapped inner section segment. A self-locking wedge system providing means of restraint or braking is inserted between each two overlapping outer and inner section segments, and a leading tie and a deformation tie are fitted at the overlap region to the respective ends of the overlapping outer and inner section segments.