Test and Evaluation of Monitoring Systems (TEM) - Wireless monitoring

The wireless monitoring system at the GTS is based on the principle of magneto-inductive data transmission. The physical properties of magnetic fields allow these systems to operate through any natural medium or medium boundary.

Photographs of the Magneto-Inductive transmitter antenna (left) and receiver (right).

Photographs of the Magneto-Inductive transmitter antenna (left) and receiver (right).

Six supplementary sensors (2 pore pressure, 2 total pressure, and 2 water content sensors) were emplaced in the bentonite section and hooked up to a battery-powered data logger embedded in the tunnel face behind the low-pH shotcrete plug. There the data are temporarily stored before they are wired to a battery-powered magneto-inductive transmitter which is also embedded in the tunnel face. Finally, the data are transmitted wirelessly to a receiver and data acquisition unit in the access tunnel in front of the plug.

TEM wireless sensors and data acquisition

Sensors and data acquisition systems in and near the low-pH shotcrete plug from both the conventional (ESDRED) and magneto-inductive (TEM) transmission systems

Placing the standard data logger and magneto-inductive transmitter in small boreholes was necessary in order to protect them from the high swelling pressures of the bentonite which is expected to reach up to 5 MPa.

Test and Evaluation of Monitoring Systems (ESDRED / TEM)

The GTS underground facilities are also available to interested 3rd parties for underground testing and research. The GTS offers cost-effective access to a fully developed, well characterised underground research facility with round the year logistical support - please contact Dr. Ingo Blechschmidt, Head of the Grimsel Test Site, for further details.