Application Note: Ground Movement in Underground Rail Tunnels

Customer Requirement

• To monitor ground movement during excavation of a new underground railway tunnel, to provide a data history and to issue alarms for excessive movement.
• To transmit data and warning alarms to personnel in the tunnel and on the surface via an existing telephone system.

Equipment

• DT515 in a local Network
• Telephone Telemetry using Modem Manager
• Alarms transmitted to Pagers
• Vibrating Wire Strain Gauges

dataTaker Solution

A number of dataTaker DT515 data loggers were installed along the tunnel, and connected together using the inbuilt dataTaker networking features. Each dataTaker monitors ground movement indicated by a series of vibrating wire strain gauges installed into the tunnel walls and ceiling.

A dataTaker's Modem Manager and modem provides a telephone telemetry link between the dataTaker network underground and computers on the surface. Realtime data, stored data and alarm states are transmitted via this link.

The Modem Manager also transmits alarm states directly to alphanumeric pagers worn by personnel on the surface and in the tunnel.

The application is supervised with dataTaker's DeLogger Pro graphical software package.