Underground—EMEA—Austria—Tunneling
Short Distances with DSI:
Supply of Ground Support Products for the Granitztal Tunnel Chain in Austria
The 130km long Koralmbahn is currently the largest project for extending
Austria’s railway network. The new section establishes a direct connection
from Graz to Klagenfurt, reducing travelling times in this area from 3 hours
to 1 hour.
After the Koralm Tunnel, the approximately
6.1km long Granitztal Tunnel Chain is the
Koralmbahn’s second longest tunnel system.
The tunnel chain is located in the 7.8km long
section between St. Andrae and Aich that is
being built by a Joint Venture consisting of
Implenia and Hochtief Infrastructure.
The tunnel chain consists of three sections –
a tunnel in the Granitz Valley that is being built
using the open cut method, and two bored
tunnels. The Deutsch Grutschen Tunnel is
2,556m long and the Langer Berg Tunnel
has a length of 2,929m. Both tunnels are
being built with 2 single track tunnel tubes
each and are connected via the 597m long
enclosure in the Granitz Valley.
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Between the double tubes of both tunnels,
crosscuts are being built approximately every
500m. The excavation of the two tunnels
will create approximately 1.3 million m³ of
excavation material, 800,000m³ of which will
be re-used for building the tunnels. The mountain ridge near the Deutsch
Grutschen Tunnel consists of Neogene
and unconsolidated Miocene sediments.
According to a cost estimate, tunnel driving
in this area was also more economical
using the NATM in comparison to a TBM.
The geology near the Langer Berg Tunnel
is characterized by tectonic fault zones
and highly changing formations so that
a flexible and adjustable construction
method was required. The tender stipulated
that the excavation had to be carried out
in accordance with the New Austrian
Tunneling Method (NATM) because the
use of a Tunnel Boring Machine (TBM)
would have involved unacceptable risks. DSI Underground Austria as a system
supplier produced and supplied all of
the ground support products that were
required to stabilize advancement, including
OMEGA-BOLT ® Expandable Friction Bolts,
SN Anchors, the DYWI ® Drill Hollow Bar
System, AT – Tubespile TM , Ø 38 x 4 mm tube
spiles, and POWER SET Self-Drilling Vacuum
Tube Spiles.