CBE Group, France

CBE designs and creates segment moulds for concrete tunnels, handling equipment, and segment manufacturing plants. CBE works on underground sites, roadworks, railways, fluid transportation and cable routing systems.
CBE takes care of pre-project engineering, design, production line and maintenance during the whole tunnel building process, coordinating their efforts with the client and the equipment providers, they also grant site-staff training and preventive maintenance on demand.
Segment moulds
The segment geometry and materials are defined according to the tunnel geometry layout. As each tunnel is unique, so are its segment and mould.The mould being entirely dependent on the segment geometry, its engineering can only be made according to the segment concrete design. Therefore, the concrete design supplied by the engineering department is a crucial step within the mould development process.
Segment Precast Plants
The installation of segments (point) while the TBM progresses, requires a constant supply of segments Any stopping of the TBM due to lack of segments or poor segment quality would be disastrous and very expensive.On the other hand, time is a key factor for concrete maturity. Even with the curing room methods required due to time limit reasons, the segments need to be stored for nearly a month before they can be used for the tunnel, and this in order to ensure the concrete maturity that will allow its mechanical resistance. Segment engineering is a process that represents an important part of the tunnel project, it requires the setting up of a precast plant, either a stationary or a carrousel-automated one.The choice between those two techniques is often cost or time driven.
Carousel Precast Plants
With this option, moulds are automatically conveyed towards the designated workstation:
  • Preparation (lubrication, accessories).
  • Laying out of the reinforcement.
  • Concreting cabin.
  • Polishing.
To be then transported to the curing room where they remain for 5 to 10 hours, depending on the concrete attributes and the segments size (thickness), before returning to the production line where the segment will be removed from the mould on the designated workstation.

This system enables a 30 to 40% increase in productivity, especially relevant for high labour-cost countries.

Segment production requires several means of handling, which are part of CBE's expertise. Among these are :
  • Vacuum lifters for demoulding and transfer of segments.
  • Demoulding and turning devices.
  • Pre-storage and storage clamps.
  • Turning frame.
  • Tilting machines.
  • Gasket glueing frame.
  • Lifting tables.
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