Engineering and construction firm J. Murphy & Sons Limited has completed a project to remove 326,000 tonnes of rock and soil, following a major landslip at the historic Harbury cutting near Leamington Spa, ahead of schedule.
Designed by Brunel in 1852, Harbury cutting, which is 34 metres deep, 91m wide and 500m long, was the largest hand-dug railway cutting in the world.
In January 2015, a major landslip saw the movement of 326,000 tonnes of rock and soil along 160 linear metres of embankment and closed the line between Leamington Spa and Banbury. Following emergency meetings with Network Rail, Murphy devised a plan to remove the landslide and re-build the entire slope, completing the works within a challenging ’40 days and 40 nights’ timescale.
The works entailed the removal of more than 320,000 tonnes of earth from the slip area and landscaping the embankment to include the creation of two slopes on a 1:2 gradient, new 30m and 4m horizontal berms, a 1:3 slope and counterfort drains.
Murphy used a drone to carry out sophisticated imaging before coordinating a 24-hour operation with heavy plant and an average 50 staff on site at all times to meet the deadline and ensure the main passenger and freight line would no longer be at risk. The drone was also used during and after the project to monitor changes across the site.
Murphy’s project manager, Paul Gorton, said: “Moving hundreds of thousands of tonnes of earth was a huge task but we were able to work around the clock to make the cutting secure and have now carried out long-term repairs to make sure the embankment is safe.
“Due to our immediate and effective response, the project was completed eight days ahead of its deadline and the line was handed back for use two and a half weeks earlier than expected.”
With a solid commitment to sustainability, Murphy has seeded the surface of the cutting so that it returns to grassland and, as the area is a site of special scientific interest (SSSI), the team worked sensitively to minimise impact on the local wildlife, which includes great crested newts, bats, badgers and several butterfly species.
With the line now fully open to passenger and freight traffic, the final element of the work will be the completion of brickwork repairs to the Victorian tunnel in April 2016.
