Mine roadway concrete arch support - has blocks to compress thickness at transitions between support segments round road perimeter

摘要

The mine roadway support has concrete segments forming arches whose centre lines between inner and outer concrete surfaces arch around to transfer into one another at points fitted with crushed blocks, parallel to the axis of the road. The transitions points between the centre lines of the respective concrete arch segments (13, 14) from breaks in which the tangents to the centre lines form obtuse angles with their apices directed into the rock surround. - The crusher blocks are spaced round the heading by at least one eighth of the roadway perimeter. They have a breadth 'b' at right angles to the road which is 0.5 to 2 times the thickness (d) at right angles to this, assuming a block yield of 50%.