A safe, long-lasting tunnel structure requires maximum precision in tunnelling. Deviations from the planned route cost time and money. This is why single shield TBMs need an absolutely reliable and approved navigation system.

The well-proven VMT system solution TUnIS Navigation TBM^Laser determines the current advance position compared to the planned tunnel axis with millimetre accuracy and in real-time using a total station and an active laser target installed in the shield.

The position and tendencies are continuously displayed to the operator. This allows vertical or horizontal curves to be easily and precisely controlled. The system furthermore provides a full documentation of the TBM drive in a database.

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VMT’s Jonatan Rodriguez Marcos interviewed Webuild SpA’s chief engineer, Mirko
Martini, on his experience working with TUnIS Navigation TBM^Laser.

Why did you choose the TUnIS Navigation TBM^Laser? Were there other alternatives or competitive solutions available?

“Based on previous experiences, the guidance system (TUnIS Navigation TBM^Laser) was always reliable and useful throughout the excavation of the tunnel. In addition, it is a tool that is well-known and appreciated by the work team and therefore possible alternatives were not taken into consideration.”

What were the main arguments that convinced you to go with the VMT systems?

“As for the guidance system (TUnIS Navigation TBM^Laser), the good previous experiences together with the knowledge of the work team. This system was also already part of the accessory package negotiated during the purchase of the Herrenknecht TBM.”

Could these VMT solutions generally fulfill the expectations? Did they perform as expected and ordered?

“The guidance system (TUnIS Navigation TBM^Laser) fulfilled as usual all expectations. The service throughout the entire project from definition to operation has always been excellent, as has always been my experience with VMT. Quick response and quality of service.”

Which were the main benefits that the systems delivered? Do you have any “hard figures” that demonstrate the benefits, for example cost reductions, reduction in staff / time etc.?

“The great reliability of the guidance system always allowed adequate decision-making within the necessary times.”

How would you rate the collaboration with VMT, in terms of:

• in negotiation/consulting phase
• during implementation
• support during the project

“Collaboration has always been excellent at all stages.”

Where there any advantages in workflow (synergy effects) in using several VMT products in the project – in terms of functionality / support etc.?

“The synergy between the VMT and HK packages represents a clear advantage since the data exchange between the two systems is more open and efficient. That the systems speak the same language and belong to the same family is a clear advantage: the systems work for the benefit of each other, and this in turn benefits the client. In my experience the HK & VMT combination has always been good.”

Would you opt for our product solution and working with VMT as partner again?

“Undoubtedly.”