Swindon sits on a complex geological boundary where the oolitic limestones of the Corallian ridge give way to the notoriously shrinkable Kimmeridge Clay that underlies much of the town centre and the expanding northern suburbs. With the water table often perched within the first three metres across the clay vales, and a history of deep weathering in the Upper Jurassic formations, pile foundation design here rarely follows a standard prescription. Our approach integrates the ground investigation data required by Eurocode 7 (BS EN 1997-1:2004) with a practical reading of the local stratigraphy — because a pile socketed into the Coral Rag member near Old Town behaves nothing like a friction pile driven into the Gault clay south of the M4. When the preliminary boreholes reveal soft alluvium overlying a variable rockhead, we often specify a CPT test campaign to refine the pile toe level before finalising the design.
In Swindon, the difference between a straightforward pile design and a claim-prone foundation is often just a metre of weathered clay that the borehole logs missed.
