Works update - June

Works update

25 June 2021

Kia ora neighbours,

In this update we will provide you with the latest construction news from Beresford Square, Mercury Lane and the mined tunnels; in addition an update on the progress of the Tunnel Boring Machine (TBM).

You can view its progress on the online TBM tracker via www.digcrl.co.nz

Excavation continues at both Mercury Lane and Beresford Square. We are currently constructing level B2 at both entrances.

This ‘top down’ construction finishes this July at B2 for Mercury Lane and will continue to B4 for Beresford Square. Below these levels the team excavate to the deepest floor B7, with the methodology then changing to ‘bottom up’ construction.

At 32 metres underground, Karangahape will be the deepest of CRL’s stations, with entrances on both Mercury Lane and Beresford Square.

Progress in Mercury Lane

Excavation for the B2 level continues with large chunks of rock being broken up under ground and then taken above ground by our long reach excavator for removal off site.

The rocks are broken up before being loaded into the truck to lessen the noise and vibration from them hitting the truck bed.

We target to complete the B2 excavation works by the end of June and will commence again in the last week of July for excavation down to B7.

We are currently about half way to completion with the excavation for the station.

Following excavation, a temporary concrete ‘blinding layer’ is poured to provide a smooth and dry surface for steel fixing works, which involve connecting steel reinforcing bars and cages to the Diaphragm Walls.

Mined Tunnels

After completing the top heading of the 223-metre southbound mined tunnel (MC30), we are now excavating the bottom bench (3-metre high floor) of the mined tunnel.

As the team move forward, preparations are being made for the arrival of Dame Whina Cooper (our tunnel boring machine) in early September. Dame Whina will be pushed through the mined tunnel on temporary rails.

As we excavate the bottom bench the team pours the concrete foundations for these temporary rails. This process is expected to take around four weeks in total.

After completion of the bottom bench the team will begin working on the adit tunnels, which are the smaller cross passages.

Another milestone for the team has been the installation of canopy tubes to enable the construction of the southern end of the second mined tunnel.

Canopy tubes provide extra supports in areas of reduced rock cover.

Tunnel Boring Machine

Dame Whina Cooper (our tunnel boring machine) TBM has begun its journey from the Mt Eden Station towards Karangahape Station.

The TBM will not bore through the Karangahape Station as this station's cavern is much larger than the others.

You can watch how it works on YouTube via the link below:
https://www.youtube.com/watch?v=7gEa05IoWXU

The TBM pushes through the Karangahape mined tunnels using inverted segments placed behind it after every push until it recommences tunneling on towards Aotea Station.

The TBM is expected to reach Karangahape Station early September 2021 and Aotea Station in November.

To see the TBM’s progress, you can view the online TBM tracker via www.digcrl.co.nz

Progress in Beresford Square

Excavation for B2 should be completed by the end of June and steel fixing for B2 has begun. In total 270 tonnes of reinforcing steel will be used for this floor.

The temporary decking has arrived and is being constructed to span across the large central opening that in future will house the entrance for escalators at the L0 slab.

The decking allows movement of the crane and trucks to drive over the opening so that they can be loaded with spoil on the other side.

Our email address is:
karangahape@linkalliance.co.nz

Our phone number is:
0800 CRL TALK (275 8255) then press 4

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Karangahape Newsletter - Works Update June 2021