The most common applications for pressure cells are: NATM tunneling method, compressive and swelling rock, Earth fill Dams, Embankments, Foundations, Stress monitoring in concrete mass, Retaining walls and diaphragm walls. Pressure cells basically consist of a pressure pad filled with de-aired oil connected to a pressure transducer with a hydraulic tube.
The size and the shape of the pressure pad is to be selected in function of the application, dimensions of the structure it will be installed in, and of the installation method.
Total earth pressure cells are one-side sensitive pressure pad connected to the pressure transducer with a rigid steel tube. The pressure transducer is usually a vibrating wire sensor due to the expected long-life function of this technology.
Vibrating wire pressure cells are generally used to monitor stress in rock, soil, concrete, or at the contact surface between concrete-soil or concrete-rock (i.e. under embankment or within tunnel concrete lining).
In tunneling often pressure cells are requested to monitor stress in the concrete lining. Sisgeo supplies two different pressure cells models:
- L112 NATM pressure cells: radial and tangential pressure cells are provided with a pressure transducer with built-in connector for direct reading using the C6002MV portable readout device;
- L111 hydraulic pressure cells: radial and tangential pressure cells shall be customized for pad shape, pad dimension, transducer model and measuring range. With this type pressure cell, both, local readings or remote monitoring are enabled.
Total earth pressure cells and L111 pressure cells can be read with a portable readout (i.e. CRD-400 readout or the New Leonardo readout) or can be operated with a datalogger (i.e. OMNIAlog data logger) for automatic data acquisition, remote data management and alerting.