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).
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.
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)