NATM pressure cells: purpose
NATM pressure cells are designed to measure stresses and pressures within shotcrete linings and at the ground–structure interface, particularly in tunnelling applications using the New Austrian Tunnelling Method (NATM).
How it works
The instrument consists of a steel cell made up of two plates welded along the perimeter and filled with an incompressible fluid. Any change in the applied load results in a corresponding variation in internal pressure, which is measured by a transducer and converted into an electrical signal.
Applications
The cells can be installed to measure radial and tangential stresses in tunnel linings, enabling the monitoring of structural behaviour during excavation and consolidation phases.
Re-pressurisation
To ensure proper stress transfer over time, the cells are equipped with a re-pressurisation valve that restores correct contact between the instrument plates and the surrounding material, even after volumetric changes in the concrete during curing.
Durability
Their robust design and high protection rating make these instruments suitable for permanent installations in harsh environments where long-term measurement reliability and stability are required.