Each of the nine slip sites had its own unique design hurdles, such as weak soil, fractured rock and steep inclines. We had to overcome multiple challenges, such as working on a narrow road with several crews at once, coordinating with civil works and strict environmental rules to protect the area from Kauri Dieback. Space was incredibly limited, so careful planning was required to navigate the drainage and paving repairs.

To expedite the works our approach was to have multiple crews on-site at the same time, tackling each of the slips simultaneously. This meant we had to be flexible with our drilling techniques to suit the specific slope and access constraints of each location. Across the nine sites, we installed 159 Micropiles, 527 Soil nails and over 2000m² erosion control matting. We also applied 210m³ of shotcrete, poured 253m³ no-fines concrete and completed 89 load tests. Our engineers were readily on hand to make design refinements as required, which was crucial for keeping the project moving and staying on schedule. We also worked closely with Ventia to ensure the project ran smoothly.

Our staged remediation programme restored stability and resilience to the slopes along Mountain Road. Our design-and-build approach meant we could deliver complex geotechnical solutions safely and efficiently, despite the challenges. We were able to restore road access and improve its long-term performance.