WORK to excavate a 14m-deep trench that will contain twin tunnels under Britomart Station and Lower Queen Street as part of Auckland’s 3.45km double-track underground City Rail Link (CRL) began on July 24.

The excavation follows nearly two years of preparation to protect Britomart Station’s historic Chief Post Office (CPO) building and stabilise the ground in readiness for the trenching and tunnel construction.

CRL contractor Downer-Soletanche Bachy Joint Venture (DSBJV) will excavate a 5m layer of ground from Lower Queen Street, which will lower the ground level to allow excavators to start digging under the CPO. A single 25m-wide trench will be excavated in Lower Queen Street and two 10m-wide trenches under the CPO.

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 the end of this year and be finished in mid-2019. The trench will then be backfilled, with Lower Queen Street reinstated and the CPO rebuilt with basement and ground floor levels. The CRL is due to be completed in 2024.
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