Factory testing is complete for the world’s first U-shape (horse shoe) shield machine by CREG that will excavate the tunnel section in Baicheng City for the Mengxi-Huazhong coal transportation railway project connecting the west area of Inner Mongolia and central China on July 17th, 2016 in Zhengzhou. 

The cutterhead of the U-shape machine is 10.95m high and 11.9m wide. Its design and manufacture is much more challenging as opposed to the circular shield machines. The U-shape machine adopts a tapered shield and two symmetric screw conveyors for muck transfer. The cutterhead is composed of nine small cutting wheels which could rotate either simultaneously or independently in different directions. In the event of shield machine rolling, several cutterheads would rotate in the same direction in order to generate a counter torque for the shield machine to rectify the deviation. 

The U-shape shield machine differs from traditional circular machines not only in section but also in construction methods. When the machine is applied to soft soil tunneling through mountains, the tunnel space utilization could be improved for 20% to 30% in comparison to circular cutting. 

It is told by industry experts that this U-shape shield machine is applicable to geologies like soft rocks and soil in arenas such as railway, highway, hydraulic engineering projects and some oil pipeline projects. Its application scope is expected to extend to the construction of underground utilities and sponge cities in the future.