Mt Eden Station piling underway
Piling, the creation of massive concrete beams in the earth, has begun at the Mt Eden Station site.
Piling is an important part of the construction process for the tunnel portal, which will first be used to launch the Tunnel Boring Machine (TBM) and will later become the entrance to the two permanent CRL tunnels that will connect Mt Eden with Auckland’s city centre.
Piling involves the use of some very large equipment, including a piling rig and crawler crane. The machines will sit on tiered, earth platforms on the side of the hill at the intersection of Flower and Nikau Streets in Eden Terrace.
The piling rig drills into the ground - up to 40 metres deep in places - using an auger inside metal tubular casings to form the pile shaft. Once the shaft has been drilled, the crawler crane lifts large metal cages (in sections up to 15 metres in length) into the shaft, to stabilise and strengthen the walls of the shaft.
Concrete is then pumped into the caged shaft, creating the pile. Together, the two machines will establish 66 piles that will be connected by rows of waler beams, creating a retaining wall that forms the ‘face’ of the tunnel portal.
Because of the large equipment needed for piling and the type of activities being carried out, there will be noise, vibration and increased truck movements on site. Concrete trucks are expected to make several deliveries per day.
The team will be monitoring the first couple of piles closely for impacts on neighbours and will give plenty of advance notice about any works that need to take place outside of normal working hours.
The piling rig will operate during normal working hours of 7am to 7pm Monday to Friday, and 7am to 2pm on Saturdays.