Farnworth Tunnels Refurbishment Monitoring – Murphy Surveys and Geodata
The latest JV project for Murphy Surveys with Geodata was to enlarge the Farnworth Up Tunnel to accommodate twin railway tracks and overhead line electrification (OLE) equipment. The Farnworth Tunnels are Grade II listed structures which are located on the Manchester to Preston Line.
A comprehensive monitoring programme was required to validate design assumptions, confirm anticipated ground/structure movement and to ensure workforce and train safety.
The objectives of the monitoring programme were as follows:
- To monitor movements in the SCL strengthened Down Tunnel to ensure railway operational standards are not compromised
- To automatically monitor any movements in the existing brickwork lining of the Down Tunnel as a result of the partial removal of the brickwork.
- To monitor track movements on the bi-directional Down line using Automatic Total Stations
- To provide an automated alarm in the event of the movements exceeding the trigger values settled.
- To report daily to the construction management using diagrams and visualisations generated with the Kronos monitoring system
- Monitoring movement of the A666 as a result of the New Tunnel construction.
- Monitoring any movement of the existing masonry portal walls during the temporary works and launch/removal of the tunnelling shield.
- To monitor the Cemetery Road Shed, structure in the zone of influence.
- To monitor ground movement between the tunnels using in-place-inclinometers wirelessly connected to the main Kronos database.