Sunshine Coast grew fast from the 1980s, transforming former pineapple farms and coastal dunes into suburbs like Buderim and Sippy Downs. That sandy, colluvial profile means many retaining walls we design sit on ground with variable bearing capacity. Before we touch a single drawing, we run a site investigation. In our experience, the most common mistake is assuming the topsoil tells the whole story. The real challenge lies beneath the fill. That is why we always pair retaining wall design with a calicata exploratory pit to visually log the soil layers and confirm the wall foundation depth.
Saturated backfill can double lateral pressure. We always design for drained conditions first, then verify with direct shear data.