The earth slipped on the side of the R240 approximately 3.3 km from Quigley’s Point on the Inishowen Peninsula, Co. Donegal. The work was to repair the slippage of the road embankment due to poor foundation and an influx of water due to a flood event. The road embankment was footed on sloping ground very close to a meandering river. The road level is approximately 14m above the riverbed. Ground water was evident due to the higher lying ground to the south of the carriageway.
McFadden Civils Ltd were awarded the contract to repair the slip and stabilise the slope holding the road above.
We set up traffic management approximately 150 m long closing one lane, then constructed an access from the road level to the toe of the slipped embankment to the works.
We liaised with neighbours, adjoining landowners, IFI and EA. Set up site offices welfare and stores with strict Covid 19 protocols. We prepared temporary work design and third-party checks.
Particular care was required to keep the river free from unfiltered/dirty water ingress from the site, and also to protect fibre optic cable in the ground at the head of the slope and OHLE
We employed a system of short excavations and reconstructs commencing at the far end of the slip and working towards the entrance that we made. The lorries that delivered the new stone carried away the defective clay. The new retaining wall was constructed in 750 mm layers of geo grid, compacted stone and reinforcement mesh bent to 68 degrees. The bank was then faced up with topsoil and seeded with native grass.