In a conventional navigation system, the total station is fixed to the tunnel wall and must be repeatedly uninstalled, moved forward, and reinstalled as the excavation progresses. This process wastes time and incurs additional costs with each disassembly and reinstallation while posing a risk to personnel and equipment. The more frequently the total station needs to be moved, the greater these disadvantages become, particularly in tight curves.

With TUnIS.moving station, only three cable-free prisms need to be moved. The total station is directly mounted on the TBM gantry, moving with the drive. Initially, the exact current position of the total station is determined using the prisms. Then the current position of the laser target is established to determine the position of the TBM. This cyclical process ensures precise TBM navigation along the tunnel axis, allowing for accurate control of both vertical and horizontal curves. As heavy total station consoles are no longer required, the segments remain undamaged and the prisms can be quickly and easily attached.

Our system undertook its initial, highly effective trials on the London Tideway Tunnel and the Grand Paris Express project. In both cases, the trials were so successful that the tunnelling operations adopted the new TUnIS.moving station system, replacing the primary VMT standard navigation system for significant portions of the advance. Roy Behrend, Chief Surveyor at BAM Nuttall, Morgan Sindall, and Balfour Beatty Joint Venture, summarised his thoughts of the system: ” TUnIS.moving station can be credited with improved time efficiency, resulting in cost savings.”
Christophe Cottanceau, Surveyor at Implenia AG, had similar experiences with the Grand Paris Express project, highlighting time saved in the field by team thanks to quicker installation of a simple prism over a large console that requires two people to handle.

We are pleased to offer this innovative assistance system to our customers to help them with efficient deployment of skilled labour and occupational safety by facilitating installation, offering remote control of the total station via a mobile app and reduced risk of laser beam exposure.

Learn more about TUnIS.moving station