The Key Technology in Constructing the Qinling Tunnel

The Qinling tunnel is the longest tunnel in China at present, 1846 km. There is 4 km of track that is over 1 000 m under surface. 80% of it lies in the extremely rigid rock segment. During the construction, the imported TBM was first used. The construction means, the characteristics, the grade standard of surrounding rock, the characteristics of supporting structure and the design of circular liner structure and prefabricated arch components adapted to TBM are studied and the machine bored per month 531 m. The issue of 9 000 m ventilation was resolved in the case of drillblasting construction from one end in a flat leading tunnel. It set the highest boring record of 456 m per month with drillblasting method in rigid rock environment. The elastic mono slab track is used in the Qinling tunnel, thus reducing the maintenance once in operation. CWR was laid in the Qinling tunnel holus bolus, which reduces the construction period. 