The Hsuehshan Tunnel (Chinese: 雪山隧道; pinyin: Xuěshān Suìdào) or "Snow Mountain" tunnel, is the longest tunnel in Taiwan, located on the Taipei-Yilan Freeway (Taiwan National Highway No. 5). It opened on June 16, 2006.
Tunnel construction began in July 1991 and took 15 years to complete and cost a total of NT$90.6 billion (US$2.83 billion) to complete.[4][5] Tunnel construction used 370,000 m3 (13,000,000 cu ft) of concrete, 2,000 kilometres (1,200 mi) of cables, and 2,000 lighting units. While excavating the tunnel, engineers encountered difficult geological problems like fractured rock and massive inflows of water, which caused severe delays. One of the three TBMs on the westbound tunnel was buried by a ground collapse. In order to speed up the tunnel boring, an additional working interface in Interchange Station No. 2 (under Ventilation Shaft No. 2) was built. Along the tunnel alignment, there are six major faults, ninety-eight fracture zones, and thirty six high-pressure groundwater sources. Hence, serious tunnel collapses with groundwater flooding took place periodically during tunnel construction. Altogether, 25 lives were lost during 15 years of construction.