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Geohazard mitigation on a historic United States monument, creating our own chapter in Hoover history.

Project Overview


The 27 kilometre four-lane motorway runs from Mackays Crossing to Linden, through Transmission Gully. Four interchanges and two new link roads connect the route to Mackays, SH58, eastern Porirua and Kenepuru with a PPP construction budget of $850M.


Part of the new road alignment required cutting back into steep slopes to be retained with two large soil nail shotcrete walls, each just over 100m in length, to enable the construction of the new interchange for the motorway.  


Geovert Solution


Geovert has vast experience drilling and anchoring in clays with  success from testing and selecting the best drilling methodology and tooling for the ground conditions.  The works consisted of the construction and testing of around 850No. 150mm diameter soil nails up to 14m in length, 100No. inclined drains to 15m and 1000m2 of reinforced shotcrete.  Works were completed without complication with destructive tests achieving loads well beyond the engineered requirements with no further issues encountered as initially expected at the commencement of works.  

Geovert’s track record and technical knowledge of drilling clay gave our client the confidence in our ability to plan for problematic ground conditions prior to commencing works with a number of drilling techniques to test if needed, or when faced with changing ground conditions, the ability to respond quickly and proactively.

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