High Commendation At The Ground Engineering Awards 2023
We are pleased to announce that we were awarded a high commendation in the UK Project with a Geotechnical Value of up to £500K category at last week’s Ground Engineering Awards.
This was for our Clementhorpe Flood Alleviation scheme.
The judges said:
“We believe Deep Soil Mixing deserve a high commendation for innovative use of a soil mixing technique to reduce carbon in an urban flood defence installation.”
The use of soil mixing on this project is a prime example of how innovation in ground engineering, sustainability and value engineering together with collaborative working with stakeholders including the EA, the Local Authority and Contractors JBA Bentley can be beneficial to not only one project but also has the potential to change flood defence work going forward.
JBA Bentley were initially looking at using secant piled walls, but this was cost prohibitive for the project. Deep Soil Mixing were approached and in collaboration with JBA Bentley an underground seepage mitigation barrier using ‘soil mixing’ was proposed. This was designed to make the ground semi-impermeable. By using soil mixing, our solution was both sustainable and cost-efficient.
Our soil mixing solution comprised a cut-off wall constructed with secant columns 5-6metres below ground, adjacent to apartments. It created a semi-impermeable barrier underground to stop the flood waters from seeping through the ground and passing underneath the above-ground flood defences.
Working with JBA Bentley prior to starting on site, Deep Soil Mixing conducted trials to find the right mix and quantity of binder and soil, to ensure specific compressive strength qualities and semi-impermeability were achieved.
Spending time with the Bentley’s prior to start on site and liaising with the Environment Agency, local councillors and residents to keep them abreast of the project proved invaluable.
The soil mixing solution implemented by Deep Soil Mixing was designed to a critical permeability factor to allow landside water to mitigate back to the river from the surrounds whilst at the same time not allowing flood waters into the homes. This involved mixing a binder into the existing ground using our double rotary mixing head mounted onto a rig to create an underground flood defence, 240 metres long and up to 6 metres deep.
The purpose-built double rotary mixing head has twin paddles that move in opposite directions to achieve the greatest soil distribution as the materials are mixed. Improving the soil mixing process enabled the mix designs to be more finely tuned and accurate, increasing both efficiency and costs benefits for the client over the industry norm of a single auger mixing head.
Unlike piling, soil mixing has zero vibration which given the close working proximity of homes combined with reduced material deliveries and plant movements minimised disruption to the homes. Utilising the existing ground also reduced disposal of material off site, reduced import and significantly lowered the carbon footprint.
