Measurements of excavation face detection .

The DS850 extrude meter was designed for:

• detect the deformations of the advance face during the excavation of a tunnel
• measure vertical settlements with great precision through repeated measurements over time (detecting the variations in displacement between the reference rings).

The system consists of: probe, cable, rods, inclinometer tube, magnetic rings and reading unit.
The extrusometric probe is made up of two wheel-carrying trolleys and by two magnetostrictive sensors.
The connection metered electrical cable is equipped with a marine grade outer sheath and a kevlar core that guarantees the reliability of the readings even in the long term.
The inspection tube it is equipped with grooves that facilitate the sliding of the probe inside the tube, while outside the magnetic rings are installed at a distance of 1m from each other, which serve to ensure good adherence to the surrounding ground. Finally, the tube is made integral with the surrounding ground by means of cementation.