Hard Rock Gripper TBM.

Illustration with legend (PDF)

Four Herrenknecht Gripper Tunnel Boring Machines (TBM) bore and secure more than 85 kilometers of the two 57-km long main tubes of the Gotthard Base Tunnel. Gripper TBMs are specialists for hard rock.

Tunnelling

With two gripper plates, the TBMs brace themselves against the rock on both sides. The thrust cylinders push the TBM forward.

Control

The right and the left grippers can be controlled individually. This means that the TBM can master curves easily.

Cutting

The rotating cutterhead presses the disc cutters with high pressure against the rock. The disc cutters break the rock into saucer-sized chips.

Removal of the excavated material

The excavated material is passed through openings in the cutterhead onto the belt conveyor and transported out of the tunnel.

Support

Directly behind the cutterhead, roof bolting units drill holes along several meters of length in order to put the roof bolts into place for rock support. Additionally steel rings, arches and mats are installed to stabilize the rock (if required by the geological conditions). A shotrete robot rotates around the TBM’s longitudinal axis to provide final rock rock. 

Back-up-system

The transport of  the excavated rock out of the tunnel and materials into the tunnel is carried out via the rear part of the machine, the back-up system.

Herrenknecht Gripper TBMs “Sissi“ and “Heidi“ in the south:

TBM diameter  Bodio-Faido: 8.83m
TBM diameter Faido-Sedrun: 9.43m
Joint Venture - southern section: TAT Consortium (Tunnel AlpTransit – Ticino): Implenia Industrial Construction, Alpine Bau GmbH, CSC Impresa Costruzioni SA, Hochtief AG, Impregilo SpA

Herrenknecht Gripper TBMs “Gabi I“ and „Gabi II“ in the north:

TBM diameter Amsteg-Sedrun: 9.58m
TBM diameter Erstfeld-Amsteg: 9.58m
Joint Venture – northern section: Arge AGN, Arbeitsgemeinschaft Gotthard-Basistunnel Nord: AGN Consortium, Gotthard Base Tunnel North: STRABAG AG Tunnelbau Schweiz (CH) / STRABAG AG (A)