City Rail Link construction work is about to move to Mount Eden for the first time.
In a few weeks, contractors will start diverting a section of the existing Mt Eden stormwater pipe and creating a new alignment between Water and Nikau Streets because the CRL will 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 ..
The Water Street shaft will be 16m deep and a 50-80 tonne crawler crane will be used to lift in equipment.
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 breakthrough.
Before work starts, two CRL-owned buildings on Mt Eden Road and Ruru Street will be demolished as part of this work.
The stormwater realignment works will finish around April next year.
The $16.5m contract was awarded to the March Bessac Joint Venture which have had extensive pipejacking and underground work experience.
March, founded in 1971, is a Christchurch-based firm, while Bessac is a French company which has been in the tunnelling business for over 40 years.
The tunneling will be done by a German-built Herrenknecht AVN machine. You can read about how it works here.