Dowse to Petone Project - (Fletcher Higgins Joint Venture) 2008 Soil Nail Wall

Part of the Dowse to Petone Project involved building a new service road at the rear of the buildings that were accessed directly off State Highway 2. The new service road cut into the toe of the hill and required a large retaining wall to be constructed. 

Project scope

Griffiths Drilling were tasked with constructing the wall from start to finish. Construction of the wall included drilling and testing a sacrificial nail for design purposes, drilling and installing production nails of various lengths, fabrication of nail heads, fixing mesh to the rock face and applying sprayed concrete to the wall.

Due to the unstable nature of the rock locally, a blinding spray was required around the area of the test nail to give a firm and regular surface to place the jacking plate against for the testing of the sacrificial nail. Once the testing was completed work on the production nails was able to commence.

The top rows were accessed by a large scaffold platform which was constructed after the blinding spray. The platform accommodated a portable drilling rig that was lifted into place. The scaffold level was lowered as the nail installation progressed. The lower rows were drilled from the ground using a multi-angled rig. All holes were drilled with a down hole hammer.

Once the nails were grouted into place, the specially fabricated nail heads were installed and a heavy galvanized steel mesh covering the whole rock face, was attached.

After installation of the mesh and drainage holes, the whole wall was sprayed with 48 cubic metres of shotcrete.

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Projects

This section highlights some key drilling projects that Griffiths Drilling have been involved in. It also includes 'Projects Since 1971' and 'Earlier Projects' pages to showcase our extensive history and experience within the New Zealand drilling industry.

Mackays to Peka Peka Expressway (M2PP)

This $630 million project will deliver approximately 18km of 4 lane expressway through Paraparaumu and Waikanae, including a new bridge over the Waikanae River. Griffiths Drilling has been part of this project from its inception.

Transmission Gully

Transmission Gully is the biggest road construction challenge in the Wellington region. We began exploration work in 2007 for Opus. Further work was undertaken in 2013 for MWH and NZTA, with detailed geotech investigations for Leighton Contractors and Coffey Geotechnical in 2014 and 15.

Tauhara Geothermal - Geotechnical Drilling Adviser & Consultant

Mel Griffiths was engaged by Contact Energy as the Geotechnical Drilling adviser for the Tauhara Geothermal Subsidence project.

Wind Farm

Limited access, steep terrain, wet slippery conditions and very high winds were complicating factors. Also the rock was very fractured due to the proximity of the main fault line.

Muldoons Corner

This is a difficult section of SH2 which needed realignment. It's located near the summit of the narrow Rimutaka Hill Rd and features tight corners, no shoulder and near vertical faces above and below the road.

Dowse to Petone

A $65 million road improvement carried out to enhance the traffic flow on SH2. Flexibility of resources was paramount on this project, which included 45 piles at 7 sites and a new service road, requiring soil nails.

Silverstream Landfill

A large landfill site serving two cities that required anchor and drainage holes in rows along the walls of the gullies. Communication was important as all work was done around the customers programme of concrete spraying.

Centre Point Wharf Piles

This project was carried out over water on a barge in the very busy Wellington Harbour. As if this wasn't enough, matters were further complicated as quality samples had to be recovered from very soft sediments.

Transpower Tower

This project involved upgrading the foundations on transmission line towers in the upper South Island. We are proud to be associated with the 2007 New Zealand Engineering Excellence Awards Supreme Award winner.

Waiwhetu Stream

This project required 35 boreholes and 23 CPTs. Sites included working on the road for bridge pile information, open public areas alongside the stream and in the confirms of industrial operations and a Holiday Park.

Projects Since 1971

A list of all the major projects undertaken by Griffiths Drilling since its inception. Work includes some of New Zealand's most challenging and largest drilling projects, including the Clyde dam, Wellington Motorway, Te Papa, Westpac Trust Stadium and the ongoing Transmission Gully work.

Projects from 1948 to 1970

Projects completed before Griffiths Drilling became an official business. They show the experience that is inherent in our drilling business today. Work includes Waikato, Waitaki, Roxborough and Cobb Valley dams, Tongariro Power and Wairakei Geothermal projects along with others.

Water Bores

We have well over 40 years experience in drilling water bores. Most have been carried out in the Wellington, Hutt Valley, Kapiti Coast and Wairarapa regions, giving us an unequaled and comprehensive knowledge of the ground aquifers within these areas.