Britomart tunnel excavation begins
We’ve started excavating the 14-metre-deep trench that will contain CRL’s twin rail tunnels under Britomart Station and Lower Queen Street.
The excavation follows two years of careful preparation work to protect Britomart Station’s historic Chief Post Office (CPO) building and support the ground before the trenching and tunnel construction begin.
Our contractor Downer-Soletanche Bachy Joint Venture (DSBJV) will start by removing a five-metre layer of ground from Lower Queen Street. This will lower the ground level sufficiently to allow excavators to start digging under the CPO building.
A single 25-metre wide trench will be excavated in Lower Queen Street and two 10-metre-wide trenches under the CPO (the two future CRL platforms will be located on the far sides of the station).
DBSJV is also completing the weight transfer of the 106-year-old Category 1-listed heritage building onto a series of underpinning frames, which will protect it from damage while CRL infrastructure is built underneath.
CRL tunnel box construction is expected to start at this location at the end of this year, once the trench excavation reaches the required 14-metre depth, and be finished in mid-2019. After this time, the trench will be backfilled, Lower Queen Street reinstated and the CPO rebuilt with basement and ground floor levels.