| 摘要 |
A composite mat comprising longitudinal and cross bars crossing one another is provided for the permanent lining of roadways in underground mining and tunnelling. The longitudinal bars of the composite mat have a vertical hook at one end and a load-displacement part, causing work of deformation when compressive and tensile forces occur, at the other opposite end. This load-displacement part to be deformed is designed as a wire which forms a hairpin-shaped horizontal loop and is additionally bent out of the loop plane. The slip ring is positioned in the curve thus formed and, after the vertical hook of the adjacent lagging mats is put in, forces recovery of the hairpin-shaped wire. The loop can be designed as a flat part enclosing the two wires of the corresponding loop or as a continuous bar, both being arranged to be displaceable, and thus enabling a joint to be formed which increases the deformation resistance and holds for a long time at a uniform height. <IMAGE>
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