High-Tech vs. Hard Rock
CREG TBM Germany GmbH builds the whole range of Hard Rock TBMs. All types of Hard Rock TBMs are customized designed for each project. We manufacture Gripper- , Single- and Double-Shield TBMs in highest quality under strongest requirements. CREG TBM Germany GmbH also manufacture Reamer TBMs, TBMs for inclined shaft (inclination up to 100%) and special machines for non-circular profiles. The boring diameter of TBMs is between 1,5m and 15m.
Our Cutter Heads for Hard Rock are in high-efficiency rock-breaking design with non-linear disc cutter arrangement for support ability in adverse geologies and small cutter spacing to enhance TBM excavating capacity. Also for small cutter heads CREG engineers applied back-loaded cutting tools technology.
Main Drive of cutter head is electric, the rotation speed is frequency
Air conditioned operator cabin, switch gear cabinets, hydraulic power packs, transformer and all other things which are needed to serve the TBM are installed on a customized designed Back-Up behind TBM.
Gripper TBM is the classic and mostly used form of TBMs in hard rock with
medium to high stand-up time (usual UCS = 100 to 300 MPa / RQD = 50 to 100 % /
joint exceeding > 0,6 m).
CREG TBM Germany GmbH builds Gripper TBMs as - Open TBM with dust shield
(acc. to the DAUB) - TBM with roof shield
- TBM with roof shield and side wings
- TBM with cutter head jacket
CREG TBM Germany GmbH design the Gripper TBMs with two versions of gripper systems – Main Kelly or Main Beam – chosen by project requirements.
Gripper TBM – Main Kelly Gripper TBM – Main Beam
QINLING Railway Tunnel Project, China Jilin Yinsong Water Diversion Tunnel Project, China
Excavation-Ø 8,83 m / Gneiss (UCS up to > 350 MPa) Excavation -Ø 8,03m / granite, limestone, tuff (UCS up to > 150 MPa)
For rock support the gripper TBMs can be equipped with several equipment like anchor drills, probe drill, mesh installer, shotcrete equipment or similar.
Single Shield TBM
Single Shield TBMs are used for tunneling projects where most of the tunnel route passes through draw rock and/or fissured rock, which requires immediate security measures to kept it from collapsing. As the name “Shield TBM” says, the TBM is built with a shield around the entire machine, to protect the crew and the machine and to support the tunnel temporary. At the tail of shield the tunnel lining (segment ring) will installed inside shield. The thrust jacks pushing directly against installed segment ring and thrust the machine forwards. The boring process is cyclic interrupted because of segment ring installation.
Single Shield TBM with active articulation
Taohe River Water Diversion and Supply Project, China
Excavation-Ø 5,75 m / ??? (UCS up to > 200 MPa)
A special variant of single shield TBMs are the Closed TBMs, used in hard rock and also in fractured rock. These special TBMs are solutions to excavate tunnels under water table were the water inflow prevented by compressed air. Also were the cutting face will supported by using the Slurry or EPM principle.
Double Shield TBM
Shield TBMs are used like Single Shield TBMs for tunneling projects where most
of the tunnel route passes through draw rock and/or fissured rock, but has the
advantage to have a continuous boring process without interruption for segment
The double Shield TBM has two main parts, the front shield with cutter head / main drive unit and the gripper shield with clamping unit / segment ring installation area. Both main parts are connected together with the thrust or telescopic jacks.
normal case the gripper shield is clamped to the tunnel wall and the thrust
jacks pushed the front shield forwards. In the same time the segment ring
installation could be done inside tail shield. Auxiliary thrust jacks inside
gripper shield supports the installed segments.
When rock conditions goes too bad, means gripper shield can’t clamp to tunnel wall, the Double Shield TBM can be used as a Single Shield TBM by using the auxiliary thrust jacks which will push the whole TBM forwards.
Double Shield TBM Double Shield TBM
Lanzhou Water Source Project, China Guadarrama Railway Project, Spain
Excavation-Ø 5,48 m / ??? (UCS up to > 200 MPa) Excavation-Ø 9,46 m / Granite (UCS up to > 250 MPa)