Norway’s longest railway Tunnel, the Follo Line project, reached a milestone on 6 July 2016 at 4pm, when the breakthrough of tunneling took place. This is the longest tunnel so far in Norway. The Follo Line is a new double track line between Oslo and the public transport center of Ski.
The breakthrough happened on the inbound Ostfold Line tube.This milestone was reached after almost a year of construction. In the next two years approximately 3500 m of tunnels will be built, this will include the entire interior construction and the track on the inbound Ostfold Line.
The project is currently the largest transport project in Norway and includes the country’s longest railway tunnel (20 km). Combined with the existing Ostfold Line, four tracks to the capital Oslo will represent more trains and faster trains on schedule.
With the increasing requirements of the railway tunnel safety, people are paying more and more attention to the higher geological anchoring technology. Traditional technology may have some shortcomings during the construction under broken rock, loose soil and conditions which are difficult to drill holes, such as fracture zones, decayed rock, gravel, sandy gravel, backfill ground. While self drilling anchor system consists of hollow anchor bar, coupler, nut, plate and sacrificial drill bit. Hollow anchor bar can be used as a drill rod, grouting pipe and source of anchoring force, which makes self drilling anchor system combine drilling, grouting and anchoring functions together. Different type of drill bits can be used according to different geological conditions so as to achieve optimal result. The application of hollow anchor bar in the railway tunnels will largely save the construction cost and speed up the construction progress.