We recently consulted on a high-rise project near Barangaroo where the design called for 40-meter piles founded in the Ashfield Shale. However, the upper 15 meters consisted of soft to firm clays with high plasticity. The structural engineer needed to know how much long-term settlement would occur. This is where the oedometer consolidation test became essential. A single test can define the pre-consolidation stress, compression index, and coefficient of consolidation. In Sydney's complex geology, where the Botany Sands and Bringelly Shale create variable conditions, this data directly affects foundation depth and slab design. We recommend pairing consolidation testing with cimentaciones-superficiales analysis when shallow layers are involved.
An oedometer test can reduce foundation costs by 15-20% when it confirms over-consolidated clays that would otherwise be conservatively designed as normally consolidated.