W Daniels Plant Hire (Groundworks)
Structural Drawing & Detailing
A new 11.6m high wind turbine was to be installed to provide power to the nearby Tamar Valley Visitor Centre, constructed as a low energy, zero fossil emission building.
The site is located adjacent to the disused Drakewalls Mine, once the richest tin mine in East Cornwall, that closed in the early 1900’s. The ground contains mine waste, which is covered by a layer of inert soil. James Lockyer Associates arranged for trial holes to be excavated to determine the ground conditions and to obtain soil samples for analysis, which confirmed the presence of arsenic contamination, commonly found in mining areas.
To achieve the required bearing pressure for the turbine foundation, the loads had to be transferred into the bedrock below the uncompacted fill material, resulting in a very deep concrete base requiring excavation and disposal of contaminated material. We were requested to provide a cost effective alternative. The solution was to have a shallow concrete foundation on bored piles into the bedrock.