The finished slope was 36 degrees, 40 metres in height and 60m wide. 250mm depth of topsoil was required, rather than the nominal 50-75mm, as cover for marginally contaminated on site fill material.
The geotechnical issues were solved using our grids. For the surface treatment, Salix installed a series of dead willow faggots at 1.5m spacing down the slope in order to physically retain the 250mm of soil cover. Willow faggots are a more environmentally sustainable alternative to cellular confinement systems and are easier to fill.
Salix then protected the 4000m2 face with HydraCX, a hydraulically applied erosion control solution that allows rapid establishment of vegetation.
“In facing the engineering challenges of the reinstatement of a landslip of over 8,000 tonnes, which required the re-use of the landslipped material into a steep faced reinforced embankment, the project required a system to control short term surface water scour, minimise mechanical disturbance of the newly applied topsoil and promote rapid vegetation growth on the newly constructed embankment face in a sustainable way. The HydraCX2 system delivered these project requirements providing rapid application, evidence of short term scour protection and substantial vegetation growth within 4 weeks of application using only biodegradable materials. The embankment is now well vegetated and holding its own against the rigours of the Welsh weather!”
Andrew Stone, BSc(Hons). IEng. MICE, RMaPS
Land Reclamation & Engineering Manager
Rhondda Cynon Taf