Winwick Wind Farm (soil stabilisation)

Faced with the challenge of constructing over three kilometres of new access track and six crane platforms on arable farmland with no suitable sources of aggregate in the local area, Jones Bros drew on its expertise in soil stabilisation to design and construct an innovative solution that was not only fit for purpose but also offered significant cost, programme and environmental benefits.

Traditionally wind farm tracks and crane platforms are constructed using geosynthetics and imported aggregates to achieve the required axle loads and bearing capacities. After analysis of the soil type at Winwick, we were able to propose a design using lime and cement to reinforce a depth of 600mm of soil, capped with a layer of recycled road planings.

Soils were stripped and stockpiled to a depth of 400mm below finished level. Our specialist rotovation plant was then used to apply an initial dose of lime to condition the soil prior to the addition of cement. The matrix was then compacted before placing excavated subsoil to form the second layer and repeating the process. The stabilised soil was expected to take 7 days to cure however we found we were able to achieve passing plate load tests within 2 days.

By taking this approach, we were able to reduce the quantity of aggregate imported to the site by over 22,000t, resulting in 2,200 less HGV movements. During the wind turbine delivery and erection phase of the works, no problems were encountered with the pavement structure, with only minor maintenance required to the granular surface on completion.