The first couple of attempts at a branch event site visit were delayed due to poor weather (not that it ever rains in the Waikato) but we finally got there on Thursday 19th April with a bunch of lucky lads and ladies. We were graced with an all-star cast of tour guides including FH/HEB Project Director Tony Dickens and Construction Manager Tony Adams. Project Geotechnical Engineer Natasha Jokhan provided technical input on various design and construction aspects. Thanks also to Tom Glenn and Shane Wilton for their technical inputs. The event was well attended by a good cross section of the Waikato geotechnical community.
Above: Looking north towards the 57m deep Summit Cut in the distance.
Above: Tony Adams describing the structural fill process.
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Above: The largest hydraulic excavator in New Zealand.
The tour started with a site induction and virtual flyover with commentary on this 15 km long, $409M construction project with ground conditions ranging from soft compressible alluvial soils to strong Greywacke. Some interesting project statistics include:
- Approximately 3.5M m3 of fill
- Geogrid reinforced Engineered fills up to 21m deep
- Fill batter gradients of 1V to 1.5H
- A 57m deep summit cut through Greywacke rock and clay (1.3 million m3 in this one cut)
- 450,000 linear metres of wick drain installed in historic mine waste materials with 2m of settlement occurring under surcharge loading
- Four bridges utilising friction and end bearing piles up to 45m deep
- Timber piles were used under bridge abutments (four bridges) for stability under seismic / lateral spread conditions
- Cut to waste volumes of 900,000m3
The site tour included a series of stops including the Taupiri Summit cut and several bridges along the new highway alignment with Q and A session at each stop with project engineers.
Thanks again to the project team for their time to lead the site tour and for their honest and open discussions on the challenges they have faced and the solutions employed to make the project fly. Construction is due to be complete in December 2019 of what will be a stunningly scenic section of New Zealand’s highway network.
Photos by Kade Croft