A ten-storey student accommodation block on Newport Road needed a soil mechanics study before piling could begin. We drilled six boreholes across the site to recover undisturbed samples from the glacial till that underlies much of Cardiff. The results showed a stiff clay layer at 4.5 m depth with SPT N-values averaging 28 blows. That data allowed the structural engineer to size the foundation piles correctly. For deeper loose layers we also performed a respuesta sismica analysis to verify the site class. Every borehole log followed BS 5930 logging standards. That gave the design team confidence from day one.
Glacial till in Cardiff shows SPT N-values between 22 and 35 – enough for spread footings but variable lateral consistency requires multiple boreholes.