Environmental and cost savings on slope stabilisation and consolidation projects are being missed as “gatekeepers” fear applying new techniques, according to Electrokinetic director Colin Jones.
Jones was speaking at the British Geotechnical Association’s evening meeting last night about the development of electrokinetic stabilisation and how it has been used successfully on some UK projects, but mostly overseas.
The technique passes a low voltage electrical current between an anode and cathode within the ground to create an electro osmotic flow that can dewater fine particle material by removing both interstitial and vicinal water.
“We are falling behind Asia in the uptake of innovative solutions,” he said. “In China they are using electrokinetic treatment of soils for mass dewatering for land reclamation. One scheme we have look at treated a 300ha area in weeks rather than the three years needed by surcharging methods.”
The company’s technique combines electro osmosis with geosynthetics to remove water from fine particle material and combine ground improvement, reinforcement, drainage and soil modification.
“The technique is not new – Cassagrande wrote about it 1939 – but it is not used as widely as it could be,” said Jones. “The gatekeepers – clients and consultants – are preventing wider use and missing out on potential costs savings.”
Electrokinetic geotechnical engineer David Alder, who also spoke at the event, detailed a number of schemes that the company has worked on in the UK to demonstrate the capability of the technique and the potential cost savings.
Alder said that the company had worked with Highways England on a number of schemes with typical sost savings for 29 to 35% compared to conventional soil nailed designs. “On the A21 in Stocks Green there was a 40% reduction in carbon footprint through not having to export material and being able to leave most of the trees in place, whereas a previous soil nailing scheme on an adjacent site had involved mass clearance and road closures,” he said.
“The approach fully meets the objectives of the Construction 2025 Industrial Strategy.”
Jones concluded that there was sufficient data now available to prove the treatment is permanent and he believes that 120 year design life is possible, making the technique directly comparable to more conventional solutions.