Engineers customising a machine to line service tunnels of a major Sydney project, instead of assembling formwork and conducting multiple pours, has provided multiple benefits.
Inspired by tunnel boring machine (TBM) technology, engineers on the Sydney Metro West project adapted and refined a Lining Erector Machine (LEM), enabling it to complete an entire tunnel ring of four segments in 60 minutes.
Each tunnel is around 700 metres-long and six metres in diameter and is being lined with precast concrete segments manufactured at the project’s Eastern Creek precast facility. So far the 55 metre-long LEM has installed 3438 precast concrete segments.
The world-first in tunnel construction method is successfully being used to line two mined service tunnels that connect to the future stabling and maintenance facility for the Sydney Metro West at Clyde.
Usually, tunnels excavated by roadheaders require cast in-situ lining unlike tunnels built by TBMs that excavate and install precast tunnel segments, lining the walls as they move along.
Using the LEM to line the service tunnels for the Sydney Metro West has avoided the assembly of large formwork sections, pumping concrete from the surface, and staging multiple pours. It only took two months to line the final service tunnel which is 762 metres in length.
The Sydney Metro West team has called the LEM approach a “game-changer” for the tunnelling industry. It not only speeds up the lining process but delivers a higher quality, water-tight finish that matches the strength and finish of TBM-made tunnels, according to the project team, and makes the job safer for tunnel workers.
About the author
Desi Corbett
Desi is the Editor of Concrete in Australia, at the helm since December 2013, and our weekly news writer since 2016. Focused on concrete and construction for more than 11 years, her expertise in this field forms part of a journalism career spanning three decades. To get in touch please email desi@corbettcomms.com