| 摘要 |
<p>The mine road, tunnel or gallery support is made of prefabricated concrete slabs curved to suit the roof of the tunnel and forming circular end segments which join up with those on adjoining slabs to form a round opening. The reinforcing bows of the slabs project into the opening to form opposing U shapes which are locked together. The two bows (2) protruding from any one slab (1) lie in parallel superposed planes. The bows take an inserted bush (4) between them adapted to the circular opening (3) between the slabs and the space between the individual bows. The bush acts as an abutment for the wedges (6) which ride axially within the bush (5) and lock against the walls in the bow openings (7) either side of the bush opening.</p> |
