Under the Karangahape Road area, the mined tunnel is progressing with the top heading to the first of the two platforms targeted .
It's smashing through with 190m of the 230m already reached under K Rd.
By June, the first tunnel will reach Beresford Square and consist of a total length of 278 metres of excavation with 23,000m3 of spoil removed and 2,700m3 of shotcrete sprayed onto the walls of the tunnel.
The Link Alliance excavation of Karangahape Station tunnels is unique in comparison to the other stations on the City Rail Link project as it is the only station that will not have its tunnels excavated by the ‘Dame Whina Cooper’ Tunnel Boring Machine (TBM).
This is because the Karangahape tunnel is larger than the TBM. Karangahape tunnels are being excavated using two roadheaders machines. Karangahape Station needs to be big enough to accommodate the underground station platforms. The TBM is 7.15m in diameter and cannot excavate beyond its size. So, Karangahape will act as a through station for the TBM where it will push itself from Mercury Lane to Beresford square to begin tunneling on to Aotea Station.
