Hollow Self Drill Anchor for Koralm Railway Tunnel
The Koralm Tunnel in Austria is the core part of the Baltic-Adriatic Corridor, a planned railway link between the cities of Gdansk in Poland and Ravenna in Italy. Once completed, the tunnel will have a length of 32.9km and cross the Koralpe Massif at a depth of up to 1,200m. The center distance between the two parallel, single-track tunnel tubes measures approx. 40m, and the tubes are connected via crossways every 500m.
To stabilize advancement, the contractor used the AT-Pipe Umbrella System with the newly developed squeezed connection system. This connection is more robust than the threaded type and permits a faster connection of the pipe umbrella tubes. Also, its elastic load bearing capacity is approximate twice as high as that of the threaded coupling.
Hollow self drill anchor was also used for pre-support in in weak ground conditions. Hollow self drill anchor system increased the stability in the working area by transferring loads in the longitudinal direction and decrease excavation induced deformations. The system increased safety in the working area. Beside this standard usage, hollow self drill anchor is often applied to increase stability in portal sections and for the re-excavation of collapsed sections in underground construction. Another application area is ground improvement and waterproofing in combination with all tunnel construction methods.