INNOVATIVE COASTAL CLIFF STABILISATION - THE SCARBOROUGH CLIFFS STABILISATION PROJECT

Abstract

Coastal cliff erosion and retreat is a common problem worldwide. Long-term erosion due to natural coastal processes have caused the iconic vibrant red cliffs of the Redcliffe peninsular (Scarborough, Queensland, Australia), to retreat landwards, which posed a potential risk to public safety and infrastructure. Investigations into coastal processes and geotechnical conditions at the site found that the retreat of the 320m long section of cliffs was largely driven by the slow notch erosion of the cliff base resulting in translational block failure of the overlying laterized cliff face and rotational collapse of the weaker cliff crest soils. To prevent continued notch erosion of the cliff base and subsequently improve the overall stability of the cliffs, a ‘lower cliff hardening’ solution was developed. This solution comprised of a coloured and textured, soilnailed, glass-fibre reinforced polymer reinforced shotcrete wall, which aimed to replicate the natural form and aesthetic of the existing lower cliff.