Owner
General Road Directorate of Albania
Client
IGH - Institut Gradevinarstva Hrvatske/Alb DOT
Cost
$1 billion USD
Timeframe
November 2009
— July 2010
Services performed
Dr. Sauer & Partners in joint venture with iC Consulenten provided mitigation and tunnel stabilisation as well as NATM redesign following a tunnel collapse.
Description
A major collapse during construction of the Thierre Tunnel in 2009 led government officials to call on NATM experts to come up with an innovative fix for the 5.6km, two-lane twin tunnel, which is part of the new Reshen Kalimash Motorway. Recommended stabilisation measures by the Dr. Sauer/iC JV such as backfilling, ribs and fibre shotcrete were implemented and halted creep movements. An alternative design was developed and replaced the original horseshoe profile by an ovoid shape. Pre-treatment, excavation works and support installation were accompanied by extensive monitoring.
Geology
The geological setting is influenced by the Alpine geosyncline resulting in a complex tectonic behaviour of a variety of igneous and metamorphic rocks cut by major fault zones.
Location
Tirana, Albania
Highlights
- Complex geological setting in hard rock
- Robust NATM design to tackle limited work force and time pressure
- Remediation without further incident or delay
Stabilisation measures: Backfill and fibre shotcrete "egg"
Ovoid shape emerging from horseshoe profile