Hamburg U4 gets set

摘要

Tunnelling work on line U4 of Germany's Hamburg metro is getting underway with a 6.57m diameter Herrenknecht Mixshield TBM adapted to the soft ground conditions to drive parts of the twin bore tubes.The Herrenknecht machine (S-440) will excavate 2,810m long stretches of the 4km tunnels being built for the U4 line between HafenCity and the downtown area.Geology along the route comprises a mixture of gravel, clay, sand and silt. The TBM will drive at depths of up to 42m below the city and parts of the port area and place a segmental lining during advance.