River Dee Estuary, UK
Shotwick Solar Park
UK’s largest ground mount utility scale solar park
Pile length optimisation
Construction phase verification / workmanship testing
South West Geotechnical was commissioned to complete a ground investigation and geotechnical assessment for a large 74MW ground mount solar park. This site lies on reclaimed land formed from sediment dredged from the River Dee Estuary. A combination of investigative methods, including window sampling, cone penetration testing, pile testing and resistivity testing in conjunction with detailed UKAS accredited laboratory testing in SWG’s in house laboratory helped develop the comprehensive ground model and initial design of foundations.
A two-post system was recommended, with relatively high edge table pull-out forces on the north-side piles.
Initial pile testing recorded marginal shaft resistance, but rather than increase the pile depth or adopt some other form of anchorage, it was decided to check what strength increase with time might be developed.
Three separate test visits gave the following resistance / time relationship for northern edge piles.
A full 100% increase in strength was seen to be gained in these soils, after being installed for 100 days, which was more than sufficient to permit the original design to be safely adopted, with significant savings for the client.