City Rail Link construction work is getting underway in Mount Eden for the first time.
Contractors will be diverting a section of the existing Mt Eden stormwater pipe and creating a new alignment between Water and Nikau Streets to help CRL create a redeveloped Mt Eden train station.
The existing stormwater pipe is in the path of the new CRL tunnels that will be built at Mt Eden.
The project has already bought more than two hectares of land around the station .
All the surface work for the stormwater diversion will be on CRL-owned property with minimal effect on traffic.
At Mt Eden, there will be shafts at Water and Nikau Streets to provide underground access for a micro tunnel-boring machine that will simultaneously excavate and install a new stormwater pipe using a pipe jacking technique and a deep access chamber at Mt Eden Road ..
Micro-tunnel boring machine
The tunneling will be done by a German-built Herrenknecht AVN machine. You can read about how it works here.
The machine was named Jeffie following a hugely popular CRL social naming contest. The most popular name was Jeff but traditionally such machines adopt a female name so Jeffie - a popular girls name in the early 1900s- was chosen.
Naming digging equipment after women is said to be a tradition that dates to the 1500s when miners prayed to to St. Barbara to keep them safe underground.
Saint Barbara is the patron saint of armourers, artillerymen, military engineers, miners and others who work with explosives because her legend associated her with lightning.
The Water Street shaft will be 16m deep and a 50-80 tonne crawler crane will be used to lift in equipment. The tunneling will be done by a German-built Herrenknecht AVN machine. You can read about how it works here.
Before the stormwater diversion, CRL needs to demolish apartments at 26 Mt Eden Road and the former Hyde Group building on the corner of Nikau and Ruru Streets. A specialist demolition contractor is undertaking this work, which will be completed in May.
A rock breaker will be used at Nikau St to break through a layer of rock that has been identified in boring investigations.
Lava from the Mt Eden volcano is present in the area of the work and until work begins, there is no certainty about how tough the ground will be to break.
Stormwater realignment works
After demolition, shafts will be dug at Water and Ruru Streets. They will launch and receive the micro tunnel boring machine that will install the replacement stormwater line. The tunnel will be completed in a single drive from Water to Ruru Streets.
The tunnel will be completed in a single drive from Water to Ruru. A third shaft at Mt Eden Rd will provide future access to the main via a manhole.
This work is expected to be completed by autumn 2019.
Water St (launch)
- 16m deep secant pile construction
- 8.5m internal diameter
Mt Eden Rd (access)
- 18m deep
- 2.5m internal diameter
Ruru St (receiving)
- 15m deep shaft
- 9.4m internal diameter
April 2018 Demolition works
May/June 2018 Shaft works, followed by pipe-jacking
Autumn 2019 Expected completion
In addition to the stormwater realignment, pollutant traps will be installed at Boston and Normandy Roads as part of the stormwater network improvements for Auckland. They will capture large and non-biodegradable waste such as litter and coarse sediment to prevent it reaching waterways.
Boston Road April-May 2018
Normanby Road: Spring 2018
Each trap takes about four weeks to install.