SH25 Ruamahunga
Drones in the air, ropes on the ground and sophisticated models in the office
Located north of Thames on State Highway 25, a major road cutting has been plagued by recurring landslips, leading to repeated closures and disruptions. Severe rainfall in early 2023 triggered three major landslides, so NZTA committed to a long-term solution to safeguard the highway with improved network resilience. Andy O helped generate an optimised solution
Partnering with Geo Stabilization New Zealand (GSI)—a leader in geohazard mitigation and ground engineering—our cutting-edge design and build services delivered results that will meet challenges into the future.
Our team, led by an IRATA-certified Senior Engineering Geologist, performed detailed geotechnical mapping of the slope with roped access. Analysing the terrain, mapping defects, and identifying failure mechanisms, we developed a clear understanding of the geological challenges.
To address that, we developed a tailored solution. This leveraged our state-of-the-art modelling tools, expert assessment of existing conditions and collaboration with GSI. The design was optimised to align with GSI’s preferred construction techniques and materials–ensuring maximum efficiency and reliability.
how did we optimise, earlier?
We divided the road cutting into three distinct work areas, each with a customized soil nail and mesh stabilization system. Our in-house drone survey technology created high-resolution digital surface models, enabling a digital twin of the site. This ensured greater certainty in construction planning and cost estimation.
Seamless Execution:
Throughout the construction phase, our Senior Engineering Geologist worked closely with GSI to adapt and enhance the design in real time, optimising performance and cost-effectiveness. Post-construction, Andy O advanced drone capabilities captured detailed as-built documentation, so all stakeholders had a clear record of the structures.
