Functions

Depending on different geological conditions, this TBM can combine any two of open-type, EPB and slurry tunneling modes to form dual-mode TBM. Only a small number of components require modification to expand functions and switch modes during construction, featuring short conversion time and low cost.

Combined EPB & Open-type Shield Model
The screw conveyor of the EPB TBM is arranged at the invert area, which can realize conventional closed EPB tunneling and switching to open-type tunneling. Under this working condition, the excavation chamber and screw conveyor do not need to be fully filled with muck. No supporting pressure is applied on the tunnel face, and the screw conveyor only functions for muck conveying. A retractable muck-collecting belt conveyor can be installed in the middle of the machine as an alternative muck discharge solution. This configuration requires additional mode-switching mechanisms on the cutterhead, and the screw conveyor can be retracted under open tunneling mode. The combined EPB and open-type shield can adopt modular basic structure design, or adopt the structure with joint muck discharge by screw conveyor and central belt conveyor.

Combined Open-type & Slurry TBM
The SPB is equipped with a slurry circulation circuit, while the open-type TBM adopts a central belt conveyor with retractable slag collecting ring for muck removal. For this combined model, both muck conveying systems are installed on the TBM and its backup system simultaneously.

Combination of EPB and Slurry TBM
For large-diameter TBMs of over 9 meters, a screw conveyor and slurry circuit can be installed together at the invert of the excavation chamber. This solution is not applicable to small-diameter machines. Mode switching requires time and incurs additional costs. Installing a stone crusher in front of the inlet grille of the slurry circuit further increases time and investment. High overall costs should be taken into account when adopting combined EPB and slurry balance shields.

Three-mode TBM 
EPB/slurry/open three-mode
Designed for projects requiring multiple operating modes, a screw conveyor and slurry circuit can be installed simultaneously at the bottom of the excavation chamber. Meanwhile, an interface for the screw conveyor is designed at the central position, allowing the screw conveyor to be relocated to the center for mucking under open-mode operation.