When completed, this 12.9 km twin tube with pilot tunnel which started in late-1991 will qualify cum laude for the Chamber of Horrors. Two 11.74 m-diameter Wirth TBMs and a 4.8 m-diameter Robbins TBM advancing from the east ran into geological problems in brittle sandstone. To date the pilot machine has suffered 10 face collapses which have had to be bypassed by hand mining, and the big machines also ground to a halt in December, 1997 after 653 m and 456 m of boring when 90 m of the westbound traffic tunnel collapsed aided by 750 lit/sec of water at 18 bar. Since then, all work has been by drill/blast, frequently in very wet and hazardous conditions in which an eleventh collapse of the pilot heading occurred. It is planned to restart the TBMs at some stage, possibly before 2000. Watch this space! April 1999.
Tamrock reports contractor RSEA is using its RMH 205 D rail jumbo to advance the Pinglin pilot tunnel. Visit www.tamrock.com for more product information. January 2000.Taiwan on 16th September, 2004 celebrated the final breakthrough, the eighth of its kind since 2000, of what is the world's 5th longest road tunnel. President Chen Shui-bian and Premier Yu Shyi-kun pushed a button to blast through the final portion of the eastbound tunnel. The 12.9 km Hsuehshan or Syueshan (Snow Mountain) tunnel is part of the 31 km Taipei-Ilan highway, or Beiyi freeway, which runs through mountains and river valleys in northeastern Taiwan. The Hsuehshan tunnel consists of two main tunnels (westbound and eastbound) and a pilot tunnel. Breakthroughs took place in July 1991 and October 2003 for the pilot tunnel, July 1993 and 14th March, 2004 for the westbound tunnel, and July 1993 and 16th September, 2004 for the eastbound tunnel.When initial work began on 15th July, 1991, small-sized TBMs were employed. In 1993, when work on the main tunnels began, two larger TBMs went into operation, one on the eastbound route and the other on the westbound route, both starting from the east portal. The machines cost roughly USD70.4 million. However, the tunnel drives were severely delayed by difficult geology, with fractured rock and massive inflows of water. Workers had also to deal with complex fault lines and other hazards that constantly delayed the project. Since work began 13 years ago, its completion date has had to be postponed four times because of countless cave-ins, floodings, mud and rock slides caused by massive inflows of groundwater. Eleven people were killed in the accidents. In order to speed up construction, drill/blast alternatives from additional working faces at the ventilation shaft II for all three tunnels and an additional drive at the interchange station II for the westbound tunnel were adopted. In December 1997, a large rush of water into the westbound lanes as well as a collapse forced to abandon the TBM, which was destroyed. The project had to be halted for one year. A smaller TBM was then used to complete the main portion of the westbound tunnel, which was achieved last year. As a result, the only TBM still being used was the one which bored its way through in the eastbound tube. That TBM completed a 6.8 km mountain section on 12th August, 2004.International experts stopped giving advice on how to tackle the painstaking project a few years ago, but Taiwan dug through the most difficult part - the eastward carriageway - of the tunnel. There were at least six geological faults and abundant groundwater in the section and the tunnel had to bore through very hard sandstone. This posed great challenges to the engineers. Once in just one day, the drilling heads of the jumbo had to be changed 13 times.The Hsuehshan tunnel will cut travelling time between Taipei and northeastern Ilan, passing through Pinglin and Luodong on the way, from more than two hours to just about 30 minutes. The Taipei-Ilan highway is scheduled to be officially opened at the end of next year, after the tunnel has been lined, and lighting, ventilation, power supply and traffic monitoring systems have been installed. Because of its complexity, the tunnel had to be built at all costs, for about USD1.8 billion.The world's longest road tunnel is the 24.5 km Laerdal in Norway, followed by the 18 km Zhongnanshan tunnel in China, presently under construction, the 16.9 km Gotthard tunnel in Switzerland and the 14 km Arlberg tunnel in Austria. Read E-News Weekly 12/2002. Visit www.motc.gov.tw 39/04.
