The slope in question is sandwiched between the A610 and the River Amber.  Over the years erosion has lead to the slippage and the meander bend of the river had contributed to this instability.

The first phase of the works was to clear the debris that had accumulated in the river.  The slope itself needed to be cleared, which was heavily vegetated, but also had a number of fallen trees resting on it.  Once completed the scour protection works could commence, installing rock rolls laid onto geotextile with turf reinforcement matting.  All of this work was carried out from the opposite bank, utilising long reach excavators.  Working this way allowed the works to the slope above to run concurrently reducing the overall programme duration.

The slope itself presented significant problems in terms of access and underground services.  With a water main running under the road, the top row of soil nails were installed using rotation only to minimise vibration.  Using our own zero tail swing excavator to install the upper nails meant that only one lane needed to be closed on the road above.  The soil nails further down the slope were installed using suspended A-Frame drilling rigs.  Once the soil nails were completed the whole face was overlaid erosion matting and rock fall netting.

The combined approach meant that CAN was able to complete the works in a very short space of time and get the road re-opened quickly.

Duration:       7 weeks

Client:            Derbyshire County Council

Location:        Ambergate, Derbyshire