Add us to your taskbar by dragging this icon RGI logo to the bottom of your screen.


Modem monitors minute movements

01 Mar 2001

Saltwood tunnel in Kent lies just 15m below a cutting for the Channel Tunnel Rail Link now under construction. To ensure that rail traffic can continue during construction, Rail Link Engineering has installed monitoring equipment in the brick-lined tunnel.

Four of Leica Geosystem's TCA2003 robotic land surveying units, calibrated to an accuracy of 1mm, survey 90 prisms embedded in the tunnel walls during a 15 min sweep every hour. Output from the Apswin Plus monitoring software is automatically compared to trigger values, and if a tolerance is passed an SMS message reporting the deformation is sent via the computer's modem to a list of mobile phones.

Leica Geosystems, Switzerland

Reader Enquiry Number 148