LU Tunnel and Track Monitoring London, UK

Key Achievements

•Construction of residential, office and commercial apartments blocks next to one of the busiest areas in London’s environment; above London Underground tunnels while the railway tracks remain in 24/7 operation.
•Design and installation of a networked automatic total station system backed up with manual precise levelling and tape extensometer readings

The project

•The masterplan provides over 3,200 new homes, nearly 2 million sq ft of commercial office space, and a further 335,000 sq ft of shops, restaurants and community uses. The site represents one of central Londons’ largest privately owned development sites extending to 22 acres and is recognized as being of major importance on a local, national and international level
•8no. ATS units networked in a single “least square” calculation solution measuring 400 high precision prisms attached to the tunnel rings and track beds.
•The system is required to establish if any movement or damage occurs to tunnels or tracks whilst the Main Contractor undertakes construction works directly above the tunnels.

The challenge

To ensure the ATS units combined in a networked solution perform as well as traditional manual surveying to allow 24/7 train operation.

The solution

It was achieved by careful planning, execution and unique calculation engine based on “least square algorithm” responsible for network adjustment. Very good correlation between manual and automatic surveys allowed to drop the manual survey frequency and rely on the automatic data on day to day basis.