The landslide, triggered by heavy rainfall in early 2022, spans over 130 meters in width, is as deep as a five-storey building, with a depth movement exceeding 15 meters. Geotechnical investigations confirm it as one of the most significant landslides impacting a road asset in the Noosa and Sunshine Coast region in the last 30 years. Extensive damage lies beneath the surface, requiring a careful restoration process.

Hazell Bros is over half-way through driving 266 steel-lined bored piles, each with a diameter of 900mm, to a depth of up to 25 meters. This includes the installation of some of the largest soil nails currently used in the southern hemisphere. The scale of the project requires an estimated use of 6,000 cubic meters of concrete, equivalent to two and a half Olympic-sized swimming pools, and 800 tonnes of steel.

The comprehensive remediation effort involves:

• A large structural frame composed of two rows of contiguous bored piers (266 in total), connected by stiffening beams and a concrete road beam.
• Tie backs anchoring the frame into the upslope.
• Horizontal drains extending into the sub-surface materials.
• Additional upslope soil anchors and header beams, as needed.
• Concrete drainage works, incorporating pre-cast/cast-in-situ culverts and lined drains.
• Roadworks including drainage layers, pavement, surfacing, signage, guardrail, and line marking.
• Earthworks for embankment stabilisation.
• Service locations.
• Implementation of Erosion and Sediment Control measures.

The recovery works are jointly funded by the Australian and Queensland Governments through the Disaster Recovery Funding Arrangements (DRFA).