008Under the financing of National 863 Program, Chinese engineers have rolled out on April

25, 2008 the first composite shield machine in the country. The machine, 6.3m across with

a maximum digging speed of 8cm per minute, will be firstly employed to build urban tube

tunnels. The new machine has a greatly enhanced geological adaptability to winding,

direction turning, and rolling error correction. It is also designed to cope with diverse

emergencies, including handling the stuck operation, safety protection, and water flushing.