New design of support frame for air placed concrete shell to be used in mining or tunnel construction

摘要

The twin-boom frame (1) consists of two parallel booms (2), radial positioned to the tunnel axis and held in place by S-shaped clamps (3). The clamps are welded to the booms, the upper hook (4) pointing to the rock and the lower hook (5) pointing towards the inner space of the tunnel. There could also be spiral shapes (6) used instead of the S-shaped clamps (3). An additional anchoring element (9), inserted between the twin booms, secures the relatively soft frame (1), in particular immediately after the concrete has been placed.