A 4.8M DIAMETER Robbins tunnel boring machine used for a pilot tunnel on a troubleridden project in Taiwan has finally broken through - nearly 11 years after boring began in December 1992.
Taiwan Transport Minister Lin Ling-san, who was present at the breakthrough, along with President Chen Shui-bian and Premier Yu Shyi-kin, has been reported as saying that whoever completes the Hsuehshan tunnel drive will have a place in Taiwan's engineering history.
The 12.9km Hsuehshan (Pinglin) tunnel is the key element on Taiwan's Beiyi highway between Taipei and Ilan. It has been blighted by ground and water inflow problems which led to the loss of 10 lives and a complete TBM since it was started.
The project comprises two main tunnels and the pilot bore running 5m below them.
The TBM driving the pilot bore was stopped more than 10 times because of ground collapses, rock and mudslides and huge water inflows.
On the main tunnels following behind, a Wirth TBM was lost completely when a collapse damaged it beyond repair as well as destroying a section of the segmental lining behind it. The problems were so great that local people believed the tunnel was destined never to be complete.
President Chen is now confident the driving of the main roadway sections of what will be Asia's longest road tunnel - and the third longest in the world - will be finished this year and the new highway section opened to traffic before the end of 2005.
When complete, the 31km Taipei-Ilan freeway will cut journey times between the two cities to around 25 minutes from two hours.