Slippery slope
Construction of a 33m-long sheet pile retaining wall to stabilise failing embankment
Working around gas mains on land adjacent to M25.
A series of 14m-long steel piles were installed along a 33m stretch of embankment.
Pile on
Over the years maintaining M25 assets we have had to stabilise a number of roadside embankments.
This scheme near to Junction 24 was carried out on behalf of client Connect Plus and involved the installation of a series of 14m-long steel piles along a 33m stretch of embankment. A second row of 6m-long piles was also installed to form a retaining wall lower down the slope.
A 100-tonne crane was used for the piling work with the piles being installed using both a vibrating and drop hammer.
Care had to be taken to ensure the work didn’t take place too close to the road and distract drivers, leading to a redesign that saw the main piling wall moved 2m down the embankment.
Balancing act: Vehicle movements are restricted to protect wildlife including over-wintering as well as nesting birds.
The Jackson team led negotiations with a local landowner.
Adjoining land
The Jackson team led negotiations with a local landowner to ensure the work could be carried out from adjoining land.
This reduced traffic management costs and the safety risk exposure to the delivery team, and meant the works could be carried out during the day rather than during short night-time lane closures – saving time, cost and reducing the impact of fatigue associated with night-time working.
Ground investigations
Prior to the piling phase, the team oversaw a series of ground investigations, which showed the location of known gas mains pipes running below the ground near the slope.
Trial holes were dug to find out data: their exact location, the diameter of the pipes, how deep they were down. Cadent engineers marked out the location of the pipes and JCE installed yellow marking flags to delineate the route.
The team developed and agreed a temporary bridge to protect the gas main where the plant equipment crossed to the work site while the slope was reinstated to its original profile.
Ground investigations proved the location of known gas mains pipes.
