Background

The Great Western Main Line north of Bristol Parkway station passes through a cutting prior to entering the two running tunnels. Investigation proved that stabilisation of the embankment slopes was needed to safeguard against any slippage onto the tracks, almost 30 metres below.

Scope of Works

Over 1500m of embankment had to be re-graded to a shallower profile, with a geotextile grass matting to be laid and tied into the slope for a sustainable ‘green’ solution. Up to 50,000m3 of material had to be moved up to and around the two tunnel entrances.

Solution

Specialist long reach excavators were proposed to work from the top of the rail embankment.  Safety procedures were agreed with Network Rail to enable work on a 'live' track.  Due to the size and slope stability constraints the initial work was completed using two machines with 24 metre reach. A larger machine with 26 metre reach was then brought in to complete the project - excavating the remaining material along the embankment and adjacent to the tunnel portals.

The works were completed without incident and avoided disruption to the train services by keeping the lines open. This project used the long reach expertise of WM Plant Hire and demonstrated the benefits of these specialist excavators over standard reach machines.