TRANSMISSION GULLY CUT 40

Slope stabilisation of a cut batter in the northern section of the 27km long road project with a certified crane platform for drilling & shotcrete

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.

Cut 40 had been previously completed but an adverse weather event caused local failures in the 60m high cut where Geovert had already installed 30m inclined drains with casing at the base of the cut in the projects slope stabilisation works.

Geovert Solution

As the cut had been complete, the remedial works became more complex as there was no access to the top of the crest, the high reach drilling was undertaken with our engineered crane basket mounted with a hydraulic drill supplied with power from 60m below. Several hundred rock bolts were installed across the face with mesh and shotcrete sprayed from the basket to stabilise the cutting.

We were established elsewhere on the project but had the ability to provide a tested and engineered high reach drilling option (without rope access) to undertake the work from our yard. This meant the drilling system and crew that mobilized to complete the work were experienced and trained to deliver the work safely and to the required specifications in a tight time frame responding to the slips.