A road between English Bicknor and Lower Lydbrook in Gloucestershire will re-open next month following electrokinetic treatment for a crack caused by a landslip last year.
The treatment sends pulses of electricity through the ground, forcing excess water out to speed up the drying out process. It has helped to make the soil stronger and stiffer, allowing the road to be built while the treatment is taking place, reducing the time it takes to complete.
This treatment will continue until the end of February and the slope will be further treated and monitored in March.
A filter drain has also been put in along the top of the road to remove water from the slope and from above the landslip next to the road. It is then drained away further down the hill.
The technique has been developed by geotechnical specialist Electrokinetic, which is overseeing the project.
“EKG slope stabilisation is being deployed to repair a section of failed sidelong embankment in deeply weathered mudstones at a site in the Forest of Dean, Gloucestershire,” said Electrokinetic chief executive John Lamont-Black.
“The electrokinetic slope repair system was chosen because it offers a cost-effective solution combining drainage reinforcement and ground improvement with a relatively light engineering touch, thus minimising the impact of the works on the site. The system involves the installation of patented electrodes into the slope, energising it with a DC voltage for approximately seven weeks and retaining the electrodes as reinforcement.
“The treated section of ground, approximately 70m in length, was divided up into three sections to optimally tune the design to the differing ground conditions and reduce costs. The electrodes yielded valuable information which enabled the use of the observational method to modify the ground model and thus trim the design during construction.”
The design team comprised Electrokinetic and Amey, working together for Gloucester County Council. The system was installed and operated by main contractor Envex.
The work is being financed from £3.3M awarded to Gloucestershire County Council through the government’s severe weather recovery scheme.